Addiction

Signs and symptoms of drug addiction can vary depending on the type of addiction. Symptoms may include:

• Continuation of drug use despite the knowledge of consequences
• Disregarding financial status when it comes to drug purchases
• Ensuring a stable supply of the drug
• Needing more of the drug over time to achieve similar effects
• Social and work life impacted due to drug use
• Unsuccessful attempts to stop drug use
• Urge to use drug regularly

Other signs and symptoms can be categorized across relevant dimensions:

{{Main|Substance use disorder}}

{{Further|Substance abuse|Substance-related disorder}}

{{addiction glossary|reverse citation order=yes}}

Drug addiction, which belongs to the class of substance-related disorders, is a chronic and relapsing brain disorder that features drug seeking and drug abuse, despite their harmful effects.{{Cite web |last=NIDA |date=13 July 2020 |title=Drug Misuse and Addiction |url=https://nida.nih.gov/publications/drugs-brains-behavior-science-addiction/drug-misuse-addiction |access-date=15 November 2022 | work = National Institute of Drug Abuse | publisher = U.S. Department of Health and Human Services }} This form of addiction changes brain circuitry such that the brain's reward system is compromised,{{Cite book |title=The Routledge handbook of philosophy and science of addiction |vauthors=Levy N |date=2019 |publisher=Routledge |isbn=978-1-138-90928-1 |veditors=Pickard H, Ahmed SH |series=Wellcome Trust–Funded Monographs and Book Chapters |place=Oxon (UK) |chapter=Chapter 5 Addiction: The belief oscillation hypothesis |doi=10.4324/9781315689197-6 |oclc=1042341025 |pmid=31017751 |chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK540394/ |s2cid=242067468}} causing functional consequences for stress management and self-control. Damage to the functions of the organs involved can persist throughout a lifetime and cause death if untreated. Substances involved with drug addiction include alcohol, nicotine, marijuana, opioids, cocaine, amphetamines, and even foods with high fat and sugar content.{{Cite web |date=17 February 2020 |title=Food addiction: Symptoms and management |url=https://www.medicalnewstoday.com/articles/319670 |access-date=15 November 2022 |website=www.medicalnewstoday.com |language=en}} Addictions can begin experimentally in social contexts and can arise from the use of prescribed medications or a variety of other measures.{{Cite web |title=Drug addiction (substance use disorder) – Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/drug-addiction/symptoms-causes/syc-20365112 |access-date=15 November 2022 |website=Mayo Clinic |language=en}}

Drug addiction has been shown to work in phenomenological, conditioning (operant and classical), cognitive models, and the cue reactivity model. However, no one model completely illustrates substance abuse.{{Cite journal |last=Drummond |first=D. Colin |date=May 3, 2002 |title=Theories of drug craving, ancient and modern |url=http://doi.wiley.com/10.1046/j.1360-0443.2001.961333.x |journal=Addiction |language=en |volume=96 |issue=1 |pages=33–46 |doi=10.1046/j.1360-0443.2001.961333.x|pmid=11177518 }}

Risk factors for addiction include:

• Aggressive behavior (particularly in childhood)
• Availability of substance
• Community economic status{{cn|date=April 2025}}
• Experimentation
• Epigenetics
• Impulsivity (attentional, motor, or non-planning)
• Lack of parental supervision
• Lack of peer refusal skills
• Mental disorders
• Method substance is taken
• Usage of substance in youth

{{Main|Food addiction}}

The diagnostic criteria for food or eating addiction has not been categorized or defined in references such as the Diagnostic and Statistical Manual of Mental Disorders (DSM or DSM-5) and is based on subjective experiences similar to substance use disorders.{{cite journal | vauthors = di Giacomo E, Aliberti F, Pescatore F, Santorelli M, Pessina R, Placenti V, Colmegna F, Clerici M | title = Disentangling binge eating disorder and food addiction: a systematic review and meta-analysis | journal = Eating and Weight Disorders | volume = 27 | issue = 6 | pages = 1963–1970 | date = August 2022 | pmid = 35041154 | pmc = 9287203 | doi = 10.1007/s40519-021-01354-7 }}{{cite journal | vauthors = Maxwell AL, Gardiner E, Loxton NJ | date = 9 February 2020 | title = Investigating the relationship between reward sensitivity, impulsivity, and food addiction: A systematic review | url = https://doi.org/10.1002/erv.2732 | journal = European Eating Disorders Review | issn = 1099-0968 | volume = 28 | issue = 4 | pages = 368–384 | doi = 10.1002/erv.2732 | pmid = 32142199 | s2cid = 212565361 | access-date = 9 March 2023 }} Food addiction may be found in those with eating disorders, though not all people with eating disorders have food addiction and not all of those with food addiction have a diagnosed eating disorder. Long-term frequent and excessive consumption of foods high in fat, salt, or sugar, such as chocolate, can produce an addiction similar to drugs since they trigger the brain's reward system, such that the individual may desire the same foods to an increasing degree over time.{{Cite web | vauthors = Goodman B | veditors = Casarella J | date = 3 September 2022 | title = Food Addiction Signs and Treatments | url = https://www.webmd.com/mental-health/eating-disorders/binge-eating-disorder/mental-health-food-addiction | access-date = 9 March 2023 | website = WebMD | language = en}} The signals sent when consuming highly palatable foods have the ability to counteract the body's signals for fullness and persistent cravings will result. Those who show signs of food addiction may develop food tolerances, in which they eat more, despite the food becoming less satisfactory.

Chocolate's sweet flavor and pharmacological ingredients are known to create a strong craving or feel 'addictive' by the consumer.{{cite book |title=Coffee, tea, chocolate, and the brain. |vauthors=Nehlig A |publisher=CRC Press |year=2004 |isbn=978-0-429-21192-8 |location=Boca Raton |pages=203–218}} A person who has a strong liking for chocolate may refer to themselves as a chocoholic.

Risk factors for developing food addiction include excessive overeating and impulsivity.

The Yale Food Addiction Scale (YFAS), version 2.0, is the current standard measure for assessing whether an individual exhibits signs and symptoms of food addiction.{{Cite web |title=Yale Food Addiction Scale |url=https://sites.lsa.umich.edu/fastlab/yale-food-addiction-scale/ |access-date=1 November 2022 |work=Food and Addiction Science & Treatment Lab |publisher=Department of Psychology, University of Michigan}} It was developed in 2009 at Yale University on the hypothesis that foods high in fat, sugar, and salt have addictive-like effects which contribute to problematic eating habits.{{cite journal |vauthors=Gearhardt AN, Corbin WR, Brownell KD |date=February 2016 |title=Development of the Yale Food Addiction Scale Version 2.0 |journal=Psychology of Addictive Behaviors |volume=30 |issue=1 |pages=113–121 |doi=10.1037/adb0000136 |pmid=26866783}} The YFAS is designed to address 11 substance-related and addictive disorders (SRADs) using a 25-item self-report questionnaire, based on the diagnostic criteria for SRADs as per DSM-5.{{cite journal |vauthors=Brunault P, Berthoz S, Gearhardt AN, Gierski F, Kaladjian A, Bertin E, Tchernof A, Biertho L, de Luca A, Hankard R, Courtois R, Ballon N, Benzerouk F, Bégin C |date=8 September 2020 |title=The Modified Yale Food Addiction Scale 2.0: Validation Among Non-Clinical and Clinical French-Speaking Samples and Comparison With the Full Yale Food Addiction Scale 2.0 |journal=Frontiers in Psychiatry |volume=11 |pages=480671 |doi=10.3389/fpsyt.2020.480671 |pmc=7509420 |pmid=33033480 |doi-access=free}} A potential food addiction diagnosis is predicted by the presence of at least two out of 11 SRADs and a significant impairment to daily activities.{{cite journal |vauthors=Hauck C, Cook B, Ellrott T |date=February 2020 |title=Food addiction, eating addiction and eating disorders |journal=The Proceedings of the Nutrition Society |volume=79 |issue=1 |pages=103–112 |doi=10.1017/S0029665119001162 |pmid=31744566 |s2cid=208186539|doi-access=free }}

The Barratt Impulsiveness Scale, specifically the BIS-11 scale, and the UPPS-P Impulsive Behavior subscales of Negative Urgency and Lack of Perseverance have been shown to have relation to food addiction.

{{Main|Behavioral addiction}}

The term behavioral addiction refers to a compulsion to engage in a natural reward – which is a behavior that is inherently rewarding (i.e., desirable or appealing) – despite adverse consequences.{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2009 | publisher = McGraw-Hill Medical | location = New York | isbn = 978-0-07-148127-4 | pages = 364–65, 375 | edition = second | chapter = Chapter 15: Reinforcement and Addictive Disorders | quote= The defining feature of addiction is compulsive, out-of-control drug use, despite negative consequences. ...
compulsive eating, shopping, gambling, and sex – so-called "natural addictions" – Indeed, addiction to both drugs and behavioral rewards may arise from similar dysregulation of the mesolimbic dopamine system.}} Preclinical evidence has demonstrated that marked increases in the expression of ΔFosB through repetitive and excessive exposure to a natural reward induces the same behavioral effects and neuroplasticity as occurs in a drug addiction.

Addiction can exist without psychotropic drugs, an idea that was popularized by psychologist Stanton Peele.{{cite journal | vauthors = Alavi SS, Ferdosi M, Jannatifard F, Eslami M, Alaghemandan H, Setare M | title = Behavioral Addiction versus Substance Addiction: Correspondence of Psychiatric and Psychological Views | journal = International Journal of Preventive Medicine | volume = 3 | issue = 4 | pages = 290–294 | date = April 2012 | pmid = 22624087 | pmc = 3354400 }} These are termed behavioral addictions. Such addictions may be passive or active, but they commonly contain reinforcing features, which are found in most addictions. Sexual behavior, eating, gambling, playing video games, and shopping are all associated with compulsive behaviors in humans and have been shown to activate the mesolimbic pathway and other parts of the reward system. Based on this evidence, sexual addiction, gambling addiction, video game addiction, and shopping addiction are classified accordingly.

{{Main|Personality theories of addiction}}

Personality theories of addiction are psychological models that associate personality traits or modes of thinking (i.e., affective states) with an individual's proclivity for developing an addiction. Data analysis demonstrates that psychological profiles of drug users and non-users have significant differences and the psychological predisposition to using different drugs may be different.{{cite book | vauthors = Fehrman E, Egan V, Gorban AN, Levesley J, Mirkes EM, Muhammad AK |title= Personality Traits and Drug Consumption. A Story Told by Data|doi = 10.1007/978-3-030-10442-9|publisher= Springer, Cham|isbn=978-3-030-10441-2 |arxiv= 2001.06520 |year= 2019|s2cid= 151160405}} Models of addiction risk that have been proposed in psychology literature include: an affect dysregulation model of positive and negative psychological affects, the reinforcement sensitivity theory of impulsiveness and behavioral inhibition, and an impulsivity model of reward sensitization and impulsiveness.{{cite journal |vauthors=Cheetham A, Allen NB, Yücel M, Lubman DI | title = The role of affective dysregulation in drug addiction | journal = Clin Psychol Rev | volume = 30 | issue = 6 | pages = 621–34 |date=August 2010| pmid = 20546986 | doi = 10.1016/j.cpr.2010.04.005 }}{{cite journal |vauthors=Franken IH, Muris P | title = BIS/BAS personality characteristics and college students' substance use|journal=Personality and Individual Differences | year = 2006 | volume = 40 | issue = 7 | pages = 1497–503 | doi = 10.1016/j.paid.2005.12.005 }}{{cite journal |vauthors=Genovese JE, Wallace D | title = Reward sensitivity and substance abuse in middle school and high school students | journal = J Genet Psychol | volume = 168 | issue = 4 | pages = 465–69 |date=December 2007| pmid = 18232522 | doi = 10.3200/GNTP.168.4.465-469 | s2cid = 207640075 }}{{cite journal |vauthors=Kimbrel NA, Nelson-Gray RO, Mitchell JT | title = Reinforcement sensitivity and maternal style as predictors of psychopathology | journal = Personality and Individual Differences |date=April 2007| volume = 42 | issue = 6 | pages = 1139–49 | doi = 10.1016/j.paid.2006.06.028 }}{{cite journal |vauthors=Dawe S, Loxton NJ | title = The role of impulsivity in the development of substance use and eating disorders | journal = Neurosci Biobehav Rev | volume = 28 | issue = 3 | pages = 343–51 |date=May 2004| pmid = 15225976 | doi = 10.1016/j.neubiorev.2004.03.007 | s2cid = 24435589 }}

The transtheoretical model of change (TTM) can point to how someone may be conceptualizing their addiction and the thoughts around it, including not being aware of their addiction.

Cognitive control and stimulus control, which is associated with operant and classical conditioning, represent opposite processes (i.e., internal vs external or environmental, respectively) that compete over the control of an individual's elicited behaviors.{{cite journal | vauthors = Washburn DA | title = The Stroop effect at 80: The competition between stimulus control and cognitive control | journal = J Exp Anal Behav | volume = 105 | issue = 1 | pages = 3–13 | year = 2016 | pmid = 26781048 | doi = 10.1002/jeab.194 | quote = Today, arguably more than at any time in history, the constructs of attention, executive functioning, and cognitive control seem to be pervasive and preeminent in research and theory. Even within the cognitive framework, however, there has long been an understanding that behavior is multiply determined, and that many responses are relatively automatic, unattended, contention-scheduled, and habitual. Indeed, the cognitive flexibility, response inhibition, and self-regulation that appear to be hallmarks of cognitive control are noteworthy only in contrast to responses that are relatively rigid, associative, and involuntary. }} Cognitive control, and particularly inhibitory control over behavior, is impaired in both addiction and attention deficit hyperactivity disorder.{{cite journal | vauthors = Diamond A | title = Executive functions | journal = Annu Rev Psychol | volume = 64 | pages = 135–68 | year = 2013 | pmid = 23020641 | pmc = 4084861 | doi = 10.1146/annurev-psych-113011-143750 | quote = Core EFs are inhibition [response inhibition (self-control – resisting temptations and resisting acting impulsively) and interference control (selective attention and cognitive inhibition)], working memory, and cognitive flexibility (including creatively thinking "outside the box," seeing anything from different perspectives, and quickly and flexibly adapting to changed circumstances). ... EFs and prefrontal cortex are the first to suffer, and suffer disproportionately, if something is not right in your life. They suffer first, and most, if you are stressed (Arnsten 1998, Liston et al. 2009, Oaten & Cheng 2005), sad (Hirt et al. 2008, von Hecker & Meiser 2005), lonely (Baumeister et al. 2002, Cacioppo & Patrick 2008, Campbell et al. 2006, Tun et al. 2012), sleep deprived (Barnes et al. 2012, Huang et al. 2007), or not physically fit (Best 2010, Chaddock et al. 2011, Hillman et al. 2008). Any of these can cause you to appear to have a disorder of EFs, such as ADHD, when you do not. You can see the deleterious effects of stress, sadness, loneliness, and lack of physical health or fitness at the physiological and neuroanatomical level in prefrontal cortex and at the behavioral level in worse EFs (poorer reasoning and problem solving, forgetting things, and impaired ability to exercise discipline and self-control). ...
EFs can be improved (Diamond & Lee 2011, Klingberg 2010). ... At any age across the life cycle EFs can be improved, including in the elderly and in infants. There has been much work with excellent results on improving EFs in the elderly by improving physical fitness (Erickson & Kramer 2009, Voss et al. 2011) ... Inhibitory control (one of the core EFs) involves being able to control one's attention, behavior, thoughts, and/or emotions to override a strong internal predisposition or external lure, and instead do what's more appropriate or needed. Without inhibitory control we would be at the mercy of impulses, old habits of thought or action (conditioned responses), and/or stimuli in the environment that pull us this way or that. Thus, inhibitory control makes it possible for us to change and for us to choose how we react and how we behave rather than being unthinking creatures of habit. It doesn't make it easy. Indeed, we usually are creatures of habit and our behavior is under the control of environmental stimuli far more than we usually realize, but having the ability to exercise inhibitory control creates the possibility of change and choice. ... The subthalamic nucleus appears to play a critical role in preventing such impulsive or premature responding (Frank 2006).}}{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2009 | publisher = McGraw-Hill Medical | location = New York | isbn = 978-0-07-148127-4 | pages = 313–21 | edition = 2nd | chapter = Chapter 13: Higher Cognitive Function and Behavioral Control | quote ={{bull}} Executive function, the cognitive control of behavior, depends on the prefrontal cortex, which is highly developed in higher primates and especially humans.
{{bull}} Working memory is a short-term, capacity-limited cognitive buffer that stores information and permits its manipulation to guide decision-making and behavior. ...
These diverse inputs and back projections to both cortical and subcortical structures put the prefrontal cortex in a position to exert what is called "top-down" control or cognitive control of behavior. ... The prefrontal cortex receives inputs not only from other cortical regions, including association cortex, but also, via the thalamus, inputs from subcortical structures subserving emotion and motivation, such as the amygdala (Chapter 14) and ventral striatum (or nucleus accumbens; Chapter 15). ...
In conditions in which prepotent responses tend to dominate behavior, such as in drug addiction, where drug cues can elicit drug seeking (Chapter 15), or in attention deficit hyperactivity disorder (ADHD; described below), significant negative consequences can result. ... ADHD can be conceptualized as a disorder of executive function; specifically, ADHD is characterized by reduced ability to exert and maintain cognitive control of behavior. Compared with healthy individuals, those with ADHD have diminished ability to suppress inappropriate prepotent responses to stimuli (impaired response inhibition) and diminished ability to inhibit responses to irrelevant stimuli (impaired interference suppression). ... Functional neuroimaging in humans demonstrates activation of the prefrontal cortex and caudate nucleus (part of the striatum) in tasks that demand inhibitory control of behavior. Subjects with ADHD exhibit less activation of the medial prefrontal cortex than healthy controls even when they succeed in such tasks and utilize different circuits. ... Early results with structural MRI show thinning of the cerebral cortex in ADHD subjects compared with age-matched controls in prefrontal cortex and posterior parietal cortex, areas involved in working memory and attention.}} Stimulus-driven behavioral responses (i.e., stimulus control) that are associated with a particular rewarding stimulus tend to dominate one's behavior in an addiction.

{{Operant conditioning}}

{{See also|Stimulus control}}

In operant conditioning, behavior is influenced by outside stimulus, such as a drug. The operant conditioning theory of learning is useful in understanding why the mood-altering or stimulating consequences of drug use can reinforce continued use (an example of positive reinforcement) and why the addicted person seeks to avoid withdrawal through continued use (an example of negative reinforcement). Stimulus control is using the absence of the stimulus or presence of a reward to influence the resulting behavior.{{cite book | vauthors = Hill R, Harris J | title = Seminars in addiction psychiatry | chapter = Psychological Approaches to Addiction | veditors = Day E | date = 2 November 2021 | publisher = Cambridge University Press | location = Cambridge | isbn = 978-1-911623-19-9 | pages = 147–169 | edition = 2nd | doi = 10.1017/9781911623199.009 | s2cid = 242036830 }}

{{See also|Cognitive control}}

Cognitive control is the intentional selection of thoughts, behaviors, and emotions, based on our environment. It has been shown that drugs alter the way our brains function, and its structure.{{cite journal | vauthors = Gould TJ | title = Addiction and cognition | journal = Addiction Science & Clinical Practice | volume = 5 | issue = 2 | pages = 4–14 | date = December 2010 | pmid = 22002448 | pmc = 3120118 }} Cognitive functions such as learning, memory, and impulse control, are affected by drugs. These effects promote drug use, as well as hinder the ability to abstain from it. The increase in dopamine release is prominent in drug use, specifically in the ventral striatum and the nucleus accumbens. Dopamine is responsible for producing pleasurable feelings, as well driving us to perform important life activities. Addictive drugs cause a significant increase in this reward system, causing a large increase in dopamine signaling as well as increase in reward-seeking behavior, in turn motivating drug use. This promotes the development of a maladaptive drug to stimulus relationship.{{cite journal | vauthors = Feltenstein MW, See RE | title = The neurocircuitry of addiction: an overview | journal = British Journal of Pharmacology | volume = 154 | issue = 2 | pages = 261–274 | date = May 2008 | pmid = 18311189 | pmc = 2442446 | doi = 10.1038/bjp.2008.51 }} Early drug use leads to these maladaptive associations, later affecting cognitive processes used for coping, which are needed to successfully abstain from them.

{{Further|Addiction vulnerability}}

A number of genetic and environmental risk factors exist for developing an addiction. Genetic and environmental risk factors each account for roughly half of an individual's risk for developing an addiction; the contribution from epigenetic risk factors to the total risk is unknown. Even in individuals with a relatively low genetic risk, exposure to sufficiently high doses of an addictive drug for a long period of time (e.g., weeks–months) can result in an addiction. Adverse childhood events are associated with negative health outcomes, such as substance use disorder. Childhood abuse or exposure to violent crime is related to developing a mood or anxiety disorder, as well as a substance dependence risk.{{cite journal | vauthors = Douglas KR, Chan G, Gelernter J, Arias AJ, Anton RF, Weiss RD, Brady K, Poling J, Farrer L, Kranzler HR | title = Adverse childhood events as risk factors for substance dependence: partial mediation by mood and anxiety disorders | journal = Addictive Behaviors | volume = 35 | issue = 1 | pages = 7–13 | date = January 2010 | pmid = 19720467 | pmc = 2763992 | doi = 10.1016/j.addbeh.2009.07.004 }}

{{Main|Epigenetics of cocaine addiction|Molecular and epigenetic mechanisms of alcoholism}}

{{Further|Alcoholism#Genetic variation|History of drinking|History of smoking|Prevalence of tobacco use}}

Genetic factors, along with socio-environmental (e.g., psychosocial) factors, have been established as significant contributors to addiction vulnerability.{{cite journal | vauthors = Saunders GR, Wang X, Chen F, Jang SK, Liu M, Wang C, etal | title = Genetic diversity fuels gene discovery for tobacco and alcohol use | journal = Nature | volume = 612 | issue = 7941 | pages = 720–724 | date = December 2022 | pmid = 36477530 | pmc = 9771818 | doi = 10.1038/s41586-022-05477-4 | publisher = Nature Research | s2cid = 254434507 | doi-access = free | bibcode = 2022Natur.612..720S }} Studies done on 350 hospitalized drug-dependent patients showed that over half met the criteria for alcohol abuse, with a role of familial factors being prevalent.{{cite journal | vauthors = Mirin SM, Weiss RD, Griffin ML, Michael JL | title = Psychopathology in drug abusers and their families | journal = Comprehensive Psychiatry | volume = 32 | issue = 1 | pages = 36–51 | date = 1 January 1991 | pmid = 2001619 | doi = 10.1016/0010-440X(91)90068-N }} Genetic factors account for 40–60% of the risk factors for alcoholism.{{cite journal | vauthors = Mayfield RD, Harris RA, Schuckit MA | title = Genetic factors influencing alcohol dependence | journal = British Journal of Pharmacology | volume = 154 | issue = 2 | pages = 275–287 | date = May 2008 | pmid = 18362899 | pmc = 2442454 | doi = 10.1038/bjp.2008.88 }} Similar rates of heritability for other types of drug addiction have been indicated, specifically in genes that encode the Alpha5 Nicotinic Acetylcholine Receptor. Knestler hypothesized in 1964 that a gene or group of genes might contribute to predisposition to addiction in several ways. For example, altered levels of a normal protein due to environmental factors may change the structure or functioning of specific brain neurons during development. These altered brain neurons could affect the susceptibility of an individual to an initial drug use experience. In support of this hypothesis, animal studies have shown that environmental factors such as stress can affect an animal's genetic expression.{{cite journal | vauthors = Kendler KS, Neale MC, Heath AC, Kessler RC, Eaves LJ | title = A twin-family study of alcoholism in women | journal = The American Journal of Psychiatry | volume = 151 | issue = 5 | pages = 707–715 | date = May 1994 | pmid = 8166312 | doi = 10.1176/ajp.151.5.707 }}

In humans, twin studies into addiction have provided some of the highest-quality evidence of this link, with results finding that if one twin is affected by addiction, the other twin is likely to be as well, and to the same substance.{{cite journal| vauthors = Crowe JR |title=Genetics of alcoholism|journal=Alcohol Health and Research World|pages=1–11|url=http://psycnet.apa.org/record/1993-22020-001|access-date=13 December 2017}} Further evidence of a genetic component is research findings from family studies which suggest that if one family member has a history of addiction, the chances of a relative or close family developing those same habits are much higher than one who has not been introduced to addiction at a young age.{{Cite news|url=https://www.addictionsandrecovery.org/is-addiction-a-disease.htm|title=The Genetics of Addiction – Is Addiction a Disease? | vauthors = Melemis SM | work = I Want to Change My Life|access-date=17 September 2018}}

The data implicating specific genes in the development of drug addiction is mixed for most genes. Many addiction studies that aim to identify specific genes focus on common variants with an allele frequency of greater than 5% in the general population. When associated with disease, these only confer a small amount of additional risk with an odds ratio of 1.1–1.3 percent; this has led to the development the rare variant hypothesis, which states that genes with low frequencies in the population (<1%) confer much greater additional risk in the development of the disease.{{cite journal | vauthors = Clarke TK, Crist RC, Kampman KM, Dackis CA, Pettinati HM, O'Brien CP, Oslin DW, Ferraro TN, Lohoff FW, Berrettini WH | title = Low frequency genetic variants in the μ-opioid receptor (OPRM1) affect risk for addiction to heroin and cocaine | journal = Neuroscience Letters | volume = 542 | pages = 71–75 | year = 2013 | pmid = 23454283 | doi = 10.1016/j.neulet.2013.02.018 | pmc=3640707}}

Genome-wide association studies (GWAS) are used to examine genetic associations with dependence, addiction, and drug use. These studies rarely identify genes from proteins previously described via animal knockout models and candidate gene analysis. Instead, large percentages of genes involved in processes such as cell adhesion are commonly identified. The important effects of endophenotypes are typically not capable of being captured by these methods. Genes identified in GWAS for drug addiction may be involved either in adjusting brain behavior before drug experiences, subsequent to them, or both.{{cite journal | vauthors = Hall FS, Drgonova J, Jain S, Uhl GR | title = Implications of genome wide association studies for addiction: are our a priori assumptions all wrong? | journal = Pharmacology & Therapeutics | volume = 140 | issue = 3 | pages = 267–79 | date = December 2013 | pmid = 23872493 | pmc = 3797854 | doi = 10.1016/j.pharmthera.2013.07.006 }}

Environmental risk factors for addiction are the experiences of an individual during their lifetime that interact with the individual's genetic composition to increase or decrease his or her vulnerability to addiction. For example, after the nationwide outbreak of COVID-19, more people quit (vs. started) smoking; and smokers, on average, reduced the quantity of cigarettes they consumed.{{cite journal | vauthors = Yang H, Ma J | title = How the COVID-19 pandemic impacts tobacco addiction: Changes in smoking behavior and associations with well-being | journal = Addictive Behaviors | volume = 119 | pages = 106917 | date = August 2021 | pmid = 33862579 | doi = 10.1016/j.addbeh.2021.106917 | pmc = 9186053 | s2cid = 233278782 | doi-access = free }} More generally, a number of different environmental factors have been implicated as risk factors for addiction, including various psychosocial stressors. The National Institute on Drug Abuse (NIDA) and studies cite lack of parental supervision, the prevalence of peer substance use, substance availability, and poverty as risk factors for substance use among children and adolescents.{{Cite news|url=https://www.drugabuse.gov/publications/preventing-drug-abuse-among-children-adolescents/chapter-1-risk-factors-protective-factors/what-are-risk-factors|title=What are risk factors and protective factors?|publisher=National Institute on Drug Abuse|access-date=13 December 2017|archive-date=30 April 2020|archive-url=https://web.archive.org/web/20200430061000/https://www.drugabuse.gov/publications/preventing-drug-abuse-among-children-adolescents/chapter-1-risk-factors-protective-factors/what-are-risk-factors|url-status=dead}} The brain disease model of addiction posits that an individual's exposure to an addictive drug is the most significant environmental risk factor for addiction.{{Cite web|title=Understanding Drug Use and Addiction|url=https://www.drugabuse.gov/publications/drugfacts/understanding-drug-use-addiction| publisher = National Institute on Drug Abuse|website=www.drugabuse.gov|date=6 June 2018|language=en|access-date=29 May 2020}} Many researchers, including neuroscientists, indicate that the brain disease model presents a misleading, incomplete, and potentially detrimental explanation of addiction.{{cite journal | vauthors = Lewis M | title = Brain Change in Addiction as Learning, Not Disease | journal = The New England Journal of Medicine | volume = 379 | issue = 16 | pages = 1551–1560 | date = October 2018 | pmid = 30332573 | doi = 10.1056/NEJMra1602872 | s2cid = 205117578 | veditors = Longo DL | quote = Addictive activities are determined neither solely by brain changes nor solely by social conditions ... the narrowing seen in addiction takes place within the behavioral repertoire, the social surround, and the brain — all at the same time. }}

The psychoanalytic theory model defines addiction as a form of defense against feelings of hopelessness and helplessness as well as a symptom of failure to regulate powerful emotions related to adverse childhood experiences (ACEs), various forms of maltreatment and dysfunction experienced in childhood. In this case, the addictive substance provides brief but total relief and positive feelings of control. The Adverse Childhood Experiences Study by the Centers for Disease Control and Prevention has shown a strong dose–response relationship between ACEs and numerous health, social, and behavioral problems throughout a person's lifespan, including substance use disorder. Children's neurological development can be permanently disrupted when they are chronically exposed to stressful events such as physical, emotional, or sexual abuse, physical or emotional neglect, witnessing violence in the household, or a parent being incarcerated or having a mental illness. As a result, the child's cognitive functioning or ability to cope with negative or disruptive emotions may be impaired. Over time, the child may adopt substance use as a coping mechanism or as a result of reduced impulse control, particularly during adolescence.{{cite web |title=Adverse Childhood Experiences |publisher=Substance Abuse and Mental Health Services Administration |location=Rockville, Maryland, United States |website=samhsa.gov |url=http://www.samhsa.gov/capt/practicing-effective-prevention/prevention-behavioral-health/adverse-childhood-experiences |access-date=26 September 2016 |archive-url=https://web.archive.org/web/20161009181048/http://www.samhsa.gov/capt/practicing-effective-prevention/prevention-behavioral-health/adverse-childhood-experiences |archive-date=9 October 2016 |url-status=dead }} Vast amounts of children who experienced abuse have gone on to have some form of addiction in their adolescence or adult life. This pathway towards addiction that is opened through stressful experiences during childhood can be avoided by a change in environmental factors throughout an individual's life and opportunities of professional help.{{cite journal | vauthors = Enoch MA | title = The role of early life stress as a predictor for alcohol and drug dependence | journal = Psychopharmacology | volume = 214 | issue = 1 | pages = 17–31 | date = March 2011 | pmid = 20596857 | pmc = 3005022 | doi = 10.1007/s00213-010-1916-6 }} If one has friends or peers who engage in drug use favorably, the chances of them developing an addiction increases. Family conflict and home management is a cause for one to become engaged in drug use.{{Cite web |url=https://learn.genetics.utah.edu/content/addiction/environment/ |title=Environmental Risk Factors |website=learn.genetics.utah.edu |access-date=17 September 2018 |archive-date=17 September 2018 |archive-url=https://web.archive.org/web/20180917105112/https://learn.genetics.utah.edu/content/addiction/environment/ |url-status=dead }}

{{Main|Social control theory}}

According to Travis Hirschi's social control theory, adolescents with stronger attachments to family, religious, academic, and other social institutions are less likely to engage in delinquent and maladaptive behavior such as drug use leading to addiction.{{Cite journal |last1=Marcos |first1=Anastasios C. |last2=Bahr |first2=Stephen J. |date=June 1988 |title=Control Theory and Adolescent Drug Use |url=http://journals.sagepub.com/doi/10.1177/0044118X88019004003 |journal=Youth & Society |language=en |volume=19 |issue=4 |pages=395–425 |doi=10.1177/0044118X88019004003 |s2cid=143860602 |issn=0044-118X}}

Adolescence represents a period of increased vulnerability for developing an addiction.{{cite journal | vauthors = Spear LP | title = The adolescent brain and age-related behavioral manifestations | journal = Neuroscience and Biobehavioral Reviews | volume = 24 | issue = 4 | pages = 417–63 | date = June 2000 | pmid = 10817843 | doi = 10.1016/s0149-7634(00)00014-2 | citeseerx = 10.1.1.461.3295 | s2cid = 14686245 }} In adolescence, the incentive-rewards systems in the brain mature well before the cognitive control center. This consequentially grants the incentive-rewards systems a disproportionate amount of power in the behavioral decision-making process. Therefore, adolescents are increasingly likely to act on their impulses and engage in risky, potentially addicting behavior before considering the consequences.{{cite journal | vauthors = Hammond CJ, Mayes LC, Potenza MN | title = Neurobiology of adolescent substance use and addictive behaviors: treatment implications | journal = Adolescent Medicine | volume = 25 | issue = 1 | pages = 15–32 | date = April 2014 | pmid = 25022184 | pmc = 4446977 }} Not only are adolescents more likely to initiate and maintain drug use, but once addicted they are more resistant to treatment and more liable to relapse.{{cite journal | vauthors = Catalano RF, Hawkins JD, Wells EA, Miller J, Brewer D | title = Evaluation of the effectiveness of adolescent drug abuse treatment, assessment of risks for relapse, and promising approaches for relapse prevention | journal = The International Journal of the Addictions | volume = 25 | issue = 9A–10A | pages = 1085–140 | pmid = 2131328 | year=1990| doi = 10.3109/10826089109081039 }}{{cite journal | vauthors = Perepletchikova F, Krystal JH, Kaufman J | title = Practitioner review: adolescent alcohol use disorders: assessment and treatment issues | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 49 | issue = 11 | pages = 1131–54 | date = November 2008 | pmid = 19017028 | pmc = 4113213 | doi = 10.1111/j.1469-7610.2008.01934.x }}

Most individuals are exposed to and use addictive drugs for the first time during their teenage years. In the United States, there were just over 2.8 million new users of illicit drugs in 2013 (7,800 new users per day); among them, 54.1% were under 18 years of age.{{cite web|title=Nationwide Trends|url=http://www.drugabuse.gov/publications/drugfacts/nationwide-trends|publisher=National Institute on Drug Abuse|access-date=15 December 2017|date=June 2015}} In 2011, there were approximately 20.6 million people in the United States over the age of 12 with an addiction.{{Cite news|url=https://www.addictioncenter.com/addiction/addiction-statistics/|title=Addiction Statistics – Facts on Drug and Alcohol Addiction|work=AddictionCenter|access-date=17 September 2018}} Over 90% of those with an addiction began drinking, smoking or using illicit drugs before the age of 18.

Individuals with comorbid (i.e., co-occurring) mental health disorders such as depression, anxiety, attention-deficit/hyperactivity disorder (ADHD) or post-traumatic stress disorder are more likely to develop substance use disorders.{{Cite web|url=https://www.samhsa.gov/capt/practicing-effective-prevention/prevention-behavioral-health/risk-protective-factors|title=Risk and Protective Factors|last=SAMHSA|publisher=Substance Abuse and Mental Health Administration|access-date=19 December 2016|archive-url=https://web.archive.org/web/20161208181514/http://www.samhsa.gov/capt/practicing-effective-prevention/prevention-behavioral-health/risk-protective-factors|archive-date=8 December 2016|url-status=dead}}{{Cite web|url=http://www.recoveryanswers.org/pressrelease/infographic-risk-factors-addiction/|title=Infographic – Risk Factors of Addiction {{!}} Recovery Research Institute|website=www.recoveryanswers.org|access-date=19 December 2016|archive-url=https://web.archive.org/web/20161217014124/http://www.recoveryanswers.org/pressrelease/infographic-risk-factors-addiction/|archive-date=17 December 2016|url-status=dead}}{{Cite web|url=http://www.mayoclinic.org/diseases-conditions/drug-addiction/basics/risk-factors/con-20020970|title=Drug addiction Risk factors – Mayo Clinic|website=www.mayoclinic.org|access-date=19 December 2016}} The {{Abbr|NIDA|National Institute on Drug Abuse}} cites early aggressive behavior as a risk factor for substance use. The National Bureau of Economic Research found that there is a "definite connection between mental illness and the use of addictive substances" and a majority of mental health patients participate in the use of these substances: 38% alcohol, 44% cocaine, and 40% cigarettes.{{Cite news|url=https://www.dualdiagnosis.org/mental-health-and-addiction/the-connection/|title=The Connection Between Mental Illness and Substance Abuse {{!}} Dual Diagnosis|work=Dual Diagnosis|access-date=17 September 2018}}

Epigenetics is the study of stable phenotypic changes that do not involve alterations in the DNA sequence.{{cite journal | vauthors = Dupont C, Armant DR, Brenner CA | title = Epigenetics: definition, mechanisms and clinical perspective | journal = Seminars in Reproductive Medicine | volume = 27 | issue = 5 | pages = 351–357 | date = September 2009 | pmid = 19711245 | pmc = 2791696 | doi = 10.1055/s-0029-1237423 }} Illicit drug use has been found to cause epigenetic changes in DNA methylation, as well as chromatin remodeling.{{cite journal | vauthors = Nielsen DA, Utrankar A, Reyes JA, Simons DD, Kosten TR | title = Epigenetics of drug abuse: predisposition or response | journal = Pharmacogenomics | volume = 13 | issue = 10 | pages = 1149–1160 | date = July 2012 | pmid = 22909205 | pmc = 3463407 | doi = 10.2217/pgs.12.94 }} The epigenetic state of chromatin may pose as a risk for the development of substance addictions. It has been found that emotional stressors, as well as social adversities may lead to an initial epigenetic response, which causes an alteration to the reward-signalling pathways. This change may predispose one to experience a positive response to drug use.

{{Main|Transgenerational epigenetic inheritance}}

Epigenetic genes and their products (e.g., proteins) are the key components through which environmental influences can affect the genes of an individual: they serve as the mechanism responsible for transgenerational epigenetic inheritance, a phenomenon in which environmental influences on the genes of a parent can affect the associated traits and behavioral phenotypes of their offspring (e.g., behavioral responses to environmental stimuli). In addiction, epigenetic mechanisms play a central role in the pathophysiology of the disease; it has been noted that some of the alterations to the epigenome which arise through chronic exposure to addictive stimuli during an addiction can be transmitted across generations, in turn affecting the behavior of one's children (e.g., the child's behavioral responses to addictive drugs and natural rewards).{{cite journal | vauthors = Vassoler FM, Sadri-Vakili G | title = Mechanisms of transgenerational inheritance of addictive-like behaviors | journal = Neuroscience | volume = 264 | pages = 198–206 | year = 2014 | pmid = 23920159 | pmc = 3872494 | doi = 10.1016/j.neuroscience.2013.07.064 | quote = However, the components that are responsible for the heritability of characteristics that make an individual more susceptible to drug addiction in humans remain largely unknown given that patterns of inheritance cannot be explained by simple genetic mechanisms (Cloninger et al., 1981; Schuckit et al., 1972). The environment plays a large role in the development of addiction as evidenced by great societal variability in drug use patterns between countries and across time (UNODC, 2012). Therefore, both genetics and the environment contribute to an individual's vulnerability to become addicted following an initial exposure to drugs of abuse. ...
The evidence presented here demonstrates that rapid environmental adaptation occurs following exposure to a number of stimuli. Epigenetic mechanisms represent the key components by which the environment can influence genetics, and they provide the missing link between genetic heritability and environmental influences on the behavioral and physiological phenotypes of the offspring.}}{{cite journal | vauthors = Yuan TF, Li A, Sun X, Ouyang H, Campos C, Rocha NB, Arias-Carrión O, Machado S, Hou G, So KF | title = Transgenerational Inheritance of Paternal Neurobehavioral Phenotypes: Stress, Addiction, Ageing and Metabolism | journal = Mol. Neurobiol. | volume = 53| issue = 9| pages = 6367–76| year = 2015 | pmid = 26572641 | doi = 10.1007/s12035-015-9526-2 | hdl = 10400.22/7331 | s2cid = 25694221 | hdl-access = free }}

The general classes of epigenetic alterations that have been implicated in transgenerational epigenetic inheritance include DNA methylation, histone modifications, and downregulation or upregulation of microRNAs. With respect to addiction, more research is needed to determine the specific heritable epigenetic alterations that arise from various forms of addiction in humans and the corresponding behavioral phenotypes from these epigenetic alterations that occur in human offspring. Based on preclinical evidence from animal research, certain addiction-induced epigenetic alterations in rats can be transmitted from parent to offspring and produce behavioral phenotypes that decrease the offspring's risk of developing an addiction.{{#tag:ref|According to a review of experimental animal models that examined the transgenerational epigenetic inheritance of epigenetic marks that occur in addiction, alterations in histone acetylation – specifically, di-acetylation of lysine residues 9 and 14 on histone 3 (i.e., H3K9ac2 and H3K14ac2) in association with BDNF gene promoters – have been shown to occur within the medial prefrontal cortex (mPFC), testes, and sperm of cocaine-addicted male rats. These epigenetic alterations in the rat mPFC result in increased BDNF gene expression within the mPFC, which in turn blunts the rewarding properties of cocaine and reduces cocaine self-administration. The male but not female offspring of these cocaine-exposed rats inherited both epigenetic marks (i.e., di-acetylation of lysine residues 9 and 14 on histone 3) within mPFC neurons, the corresponding increase in BDNF expression within mPFC neurons, and the behavioral phenotype associated with these effects (i.e., a reduction in cocaine reward, resulting in reduced cocaine-seeking by these male offspring). Consequently, the transmission of these two cocaine-induced epigenetic alterations (i.e., H3K9ac2 and H3K14ac2) in rats from male fathers to male offspring served to reduce the offspring's risk of developing an addiction to cocaine. {{As of|2018|post=,}} neither the heritability of these epigenetic marks in humans nor the behavioral effects of the marks within human mPFC neurons has been established.|group="note"}} More generally, the heritable behavioral phenotypes that are derived from addiction-induced epigenetic alterations and transmitted from parent to offspring may serve to either increase or decrease the offspring's risk of developing an addiction.

Addiction is a disorder of the brain's reward system developing through transcriptional and epigenetic mechanisms as a result of chronically high levels of exposure to an addictive stimulus (e.g., eating food, the use of cocaine, engagement in sexual activity, participation in high-thrill cultural activities such as gambling, etc.) over extended time. DeltaFosB (ΔFosB), a gene transcription factor, is a critical component and common factor in the development of virtually all forms of behavioral and drug addictions. Two decades of research into ΔFosB's role in addiction have demonstrated that addiction arises, and the associated compulsive behavior intensifies or attenuates, along with the overexpression of ΔFosB in the D1-type medium spiny neurons of the nucleus accumbens. Due to the causal relationship between ΔFosB expression and addictions, it is used preclinically as an addiction biomarker.{{cite journal | vauthors = Ruffle JK | title = Molecular neurobiology of addiction: what's all the (Δ)FosB about? | journal = Am. J. Drug Alcohol Abuse | volume = 40 | issue = 6 | pages = 428–37 | date = November 2014 | pmid = 25083822 | doi = 10.3109/00952990.2014.933840 | s2cid = 19157711 | quote = ΔFosB is an essential transcription factor implicated in the molecular and behavioral pathways of addiction following repeated drug exposure. The formation of ΔFosB in multiple brain regions, and the molecular pathway leading to the formation of AP-1 complexes is well understood. The establishment of a functional purpose for ΔFosB has allowed further determination as to some of the key aspects of its molecular cascades[...]As a consequence of our improved understanding of ΔFosB in addiction, it is possible to evaluate the addictive potential of current medications (119), as well as use it as a biomarker for assessing the efficacy of therapeutic interventions (121,122,124). Some of these proposed interventions have limitations (125) or are in their infancy (75). However, it is hoped that some of these preliminary findings may lead to innovative treatments, which are much needed in addiction.}}{{cite journal | vauthors = Biliński P, Wojtyła A, Kapka-Skrzypczak L, Chwedorowicz R, Cyranka M, Studziński T | title = Epigenetic regulation in drug addiction | journal = Ann. Agric. Environ. Med. | volume = 19 | issue = 3 | pages = 491–96 | year = 2012 | pmid = 23020045 |url=http://www.aaem.pl/fulltext.php?ICID=1010966 | quote = [...]ΔFosB is considered a primary and causative transcription factor in creating new neural connections in the reward centre, prefrontal cortex, and other regions of the limbic system. This is reflected in the increased, stable and long-lasting level of sensitivity to cocaine and other drugs, and tendency to relapse even after long periods of abstinence.}} ΔFosB expression in these neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement, while decreasing sensitivity to aversion.{{#tag:ref|A decrease in aversion sensitivity, in simpler terms, means that an individual's behavior is less likely to be influenced by undesirable outcomes.|group="note"|name="ΔFosB behaviors"}}

{{Transcription factor glossary|width=610px}}

{{Psychostimulant addiction|Colorcode=yes|align=right}}

Chronic addictive drug use causes alterations in gene expression in the mesocorticolimbic projection.{{cite journal |vauthors=Hyman SE, Malenka RC, Nestler EJ |title=Neural mechanisms of addiction: the role of reward-related learning and memory |journal=Annu. Rev. Neurosci. |volume=29 |pages=565–98 |year=2006 |pmid=16776597 |doi=10.1146/annurev.neuro.29.051605.113009 }}{{cite journal |vauthors=Steiner H, Van Waes V |title=Addiction-related gene regulation: risks of exposure to cognitive enhancers vs. other psychostimulants |journal=Prog. Neurobiol. |volume=100 |pages=60–80 |date=January 2013 |pmid=23085425 |pmc=3525776 |doi=10.1016/j.pneurobio.2012.10.001 }} The most important transcription factors that produce these alterations are ΔFosB, cAMP response element binding protein (CREB), and nuclear factor kappa B (NF-κB). ΔFosB is the most significant biomolecular mechanism in addiction because the overexpression of ΔFosB in the D1-type medium spiny neurons in the nucleus accumbens is necessary and sufficient for many of the neural adaptations and behavioral effects (e.g., expression-dependent increases in drug self-administration and reward sensitization) seen in drug addiction. ΔFosB expression in nucleus accumbens D1-type medium spiny neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement while decreasing sensitivity to aversion. ΔFosB has been implicated in mediating addictions to many different drugs and drug classes, including alcohol, amphetamine and other substituted amphetamines, cannabinoids, cocaine, methylphenidate, nicotine, opiates, phenylcyclidine, and propofol, among others.{{cite web | title=Alcoholism – Homo sapiens (human) | url=http://www.genome.jp/kegg-bin/show_pathway?hsa05034+2354 | work=KEGG Pathway | access-date=10 April 2014 | author=Kanehisa Laboratories | date=2 August 2013}}{{cite journal | vauthors = Kim Y, Teylan MA, Baron M, Sands A, Nairn AC, Greengard P | title = Methylphenidate-induced dendritic spine formation and DeltaFosB expression in nucleus accumbens | journal = Proc. Natl. Acad. Sci. USA | volume = 106 | issue = 8 | pages = 2915–20 | date = February 2009 | pmid = 19202072 | pmc = 2650365 | doi = 10.1073/pnas.0813179106 | quote = | bibcode = 2009PNAS..106.2915K| doi-access = free }} ΔJunD, a transcription factor, and G9a, a histone methyltransferase, both oppose the function of ΔFosB and inhibit increases in its expression.{{cite journal | vauthors = Nestler EJ | title = Epigenetic mechanisms of drug addiction | journal = Neuropharmacology | volume = 76 | issue = Pt B | pages = 259–68 | date = January 2014 | pmid = 23643695 | pmc = 3766384 | doi = 10.1016/j.neuropharm.2013.04.004 | quote = Short-term increases in histone acetylation generally promote behavioral responses to the drugs, while sustained increases oppose cocaine's effects, based on the actions of systemic or intra-NAc administration of HDAC inhibitors. ... Genetic or pharmacological blockade of G9a in the NAc potentiates behavioral responses to cocaine and opiates, whereas increasing G9a function exerts the opposite effect (Maze et al., 2010; Sun et al., 2012a). Such drug-induced downregulation of G9a and H3K9me2 also sensitizes animals to the deleterious effects of subsequent chronic stress (Covington et al., 2011). Downregulation of G9a increases the dendritic arborization of NAc neurons, and is associated with increased expression of numerous proteins implicated in synaptic function, which directly connects altered G9a/H3K9me2 in the synaptic plasticity associated with addiction (Maze et al., 2010).
G9a appears to be a critical control point for epigenetic regulation in NAc, as we know it functions in two negative feedback loops. It opposes the induction of ΔFosB, a long-lasting transcription factor important for drug addiction (Robison and Nestler, 2011), while ΔFosB in turn suppresses G9a expression (Maze et al., 2010; Sun et al., 2012a). ... Also, G9a is induced in NAc upon prolonged HDAC inhibition, which explains the paradoxical attenuation of cocaine's behavioral effects seen under these conditions, as noted above (Kennedy et al., 2013). GABAA receptor subunit genes are among those that are controlled by this feedback loop. Thus, chronic cocaine, or prolonged HDAC inhibition, induces several GABAA receptor subunits in NAc, which is associated with increased frequency of inhibitory postsynaptic currents (IPSCs). In striking contrast, combined exposure to cocaine and HDAC inhibition, which triggers the induction of G9a and increased global levels of H3K9me2, leads to blockade of GABAA receptor and IPSC regulation. }} Increases in nucleus accumbens ΔJunD expression (via viral vector-mediated gene transfer) or G9a expression (via pharmacological means) reduces, or with a large increase can even block, many of the neural and behavioral alterations that result from chronic high-dose use of addictive drugs (i.e., the alterations mediated by ΔFosB).

ΔFosB plays an important role in regulating behavioral responses to natural rewards, such as palatable food, sex, and exercise.{{cite journal |vauthors=Blum K, Werner T, Carnes S, Carnes P, Bowirrat A, Giordano J, Oscar-Berman M, Gold M | title = Sex, drugs, and rock 'n' roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms | journal = Journal of Psychoactive Drugs | volume = 44 | issue = 1 | pages = 38–55 | year = 2012 | pmid = 22641964 | pmc = 4040958 | doi = 10.1080/02791072.2012.662112| quote = It has been found that deltaFosB gene in the NAc is critical for reinforcing effects of sexual reward. Pitchers and colleagues (2010) reported that sexual experience was shown to cause DeltaFosB accumulation in several limbic brain regions including the NAc, medial pre-frontal cortex, VTA, caudate, and putamen, but not the medial preoptic nucleus. Next, the induction of c-Fos, a downstream (repressed) target of DeltaFosB, was measured in sexually experienced and naive animals. The number of mating-induced c-Fos-IR cells was significantly decreased in sexually experienced animals compared to sexually naive controls. Finally, DeltaFosB levels and its activity in the NAc were manipulated using viral-mediated gene transfer to study its potential role in mediating sexual experience and experience-induced facilitation of sexual performance. Animals with DeltaFosB overexpression displayed enhanced facilitation of sexual performance with sexual experience relative to controls. In contrast, the expression of DeltaJunD, a dominant-negative binding partner of DeltaFosB, attenuated sexual experience-induced facilitation of sexual performance, and stunted long-term maintenance of facilitation compared to DeltaFosB overexpressing group. Together, these findings support a critical role for DeltaFosB expression in the NAc in the reinforcing effects of sexual behavior and sexual experience-induced facilitation of sexual performance. ... both drug addiction and sexual addiction represent pathological forms of neuroplasticity along with the emergence of aberrant behaviors involving a cascade of neurochemical changes mainly in the brain's rewarding circuitry. }} Natural rewards, like drugs of abuse, induce gene expression of ΔFosB in the nucleus accumbens, and chronic acquisition of these rewards can result in a similar pathological addictive state through ΔFosB overexpression.{{cite journal | vauthors = Olsen CM | title = Natural rewards, neuroplasticity, and non-drug addictions | journal = Neuropharmacology | volume = 61 | issue = 7 | pages = 1109–22 |date=December 2011 | pmid = 21459101 | pmc = 3139704 | doi = 10.1016/j.neuropharm.2011.03.010 | quote = Functional neuroimaging studies in humans have shown that gambling (Breiter et al, 2001), shopping (Knutson et al, 2007), orgasm (Komisaruk et al, 2004), playing video games (Koepp et al, 1998; Hoeft et al, 2008) and the sight of appetizing food (Wang et al, 2004a) activate many of the same brain regions (i.e., the mesocorticolimbic system and extended amygdala) as drugs of abuse (Volkow et al, 2004). ... Cross-sensitization is also bidirectional, as a history of amphetamine administration facilitates sexual behavior and enhances the associated increase in NAc DA ... As described for food reward, sexual experience can also lead to activation of plasticity-related signaling cascades. The transcription factor delta FosB is increased in the NAc, PFC, dorsal striatum, and VTA following repeated sexual behavior (Wallace et al., 2008; Pitchers et al., 2010b). This natural increase in delta FosB or viral overexpression of delta FosB within the NAc modulates sexual performance, and NAc blockade of delta FosB attenuates this behavior (Hedges et al, 2009; Pitchers et al., 2010b). Further, viral overexpression of delta FosB enhances the conditioned place preference for an environment paired with sexual experience (Hedges et al., 2009). ... In some people, there is a transition from "normal" to compulsive engagement in natural rewards (such as food or sex), a condition that some have termed behavioral or non-drug addictions (Holden, 2001; Grant et al., 2006a). ... In humans, the role of dopamine signaling in incentive-sensitization processes has recently been highlighted by the observation of a dopamine dysregulation syndrome in some people taking dopaminergic drugs. This syndrome is characterized by a medication-induced increase in (or compulsive) engagement in non-drug rewards such as gambling, shopping, or sex (Evans et al, 2006; Aiken, 2007; Lader, 2008)."}}
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139704/table/T1/ Table 1: Summary of plasticity observed following exposure to drug or natural reinforcers]" Consequently, ΔFosB is the key transcription factor involved in addictions to natural rewards (i.e., behavioral addictions) as well;{{cite journal |vauthors=Robison AJ, Nestler EJ | title = Transcriptional and epigenetic mechanisms of addiction | journal = Nat. Rev. Neurosci. | volume = 12 | issue = 11 | pages = 623–37 |date=November 2011 | pmid = 21989194 | pmc = 3272277 | doi = 10.1038/nrn3111 | quote = ΔFosB has been linked directly to several addiction-related behaviors ... Importantly, genetic or viral overexpression of ΔJunD, a dominant negative mutant of JunD which antagonizes ΔFosB- and other AP-1-mediated transcriptional activity, in the NAc or OFC blocks these key effects of drug exposure^14,22–24. This indicates that ΔFosB is both necessary and sufficient for many of the changes wrought in the brain by chronic drug exposure. ΔFosB is induced in D1-type NAc MSNs by chronic consumption of several natural rewards, including sucrose, high fat food, sex, wheel running, where it promotes that consumption^14,26–30. This implicates ΔFosB in the regulation of natural rewards under normal conditions and perhaps during pathological addictive-like states. }} in particular, ΔFosB in the nucleus accumbens is critical for the reinforcing effects of sexual reward. Research on the interaction between natural and drug rewards suggests that dopaminergic psychostimulants (e.g., amphetamine) and sexual behavior act on similar biomolecular mechanisms to induce ΔFosB in the nucleus accumbens and possess bidirectional cross-sensitization effects that are mediated through ΔFosB.{{cite journal |vauthors=Pitchers KK, Vialou V, Nestler EJ, Laviolette SR, Lehman MN, Coolen LM | title = Natural and drug rewards act on common neural plasticity mechanisms with ΔFosB as a key mediator |journal=The Journal of Neuroscience |volume=33 | issue = 8 | pages = 3434–42 |date=February 2013 | pmid = 23426671 | pmc = 3865508 | doi = 10.1523/JNEUROSCI.4881-12.2013 | quote = Drugs of abuse induce neuroplasticity in the natural reward pathway, specifically the nucleus accumbens (NAc), thereby causing development and expression of addictive behavior. ... Together, these findings demonstrate that drugs of abuse and natural reward behaviors act on common molecular and cellular mechanisms of plasticity that control vulnerability to drug addiction, and that this increased vulnerability is mediated by ΔFosB and its downstream transcriptional targets. ... Sexual behavior is highly rewarding (Tenk et al., 2009), and sexual experience causes sensitized drug-related behaviors, including cross-sensitization to amphetamine (Amph)-induced locomotor activity (Bradley and Meisel, 2001; Pitchers et al., 2010a) and enhanced Amph reward (Pitchers et al., 2010a). Moreover, sexual experience induces neural plasticity in the NAc similar to that induced by psychostimulant exposure, including increased dendritic spine density (Meisel and Mullins, 2006; Pitchers et al., 2010a), altered glutamate receptor trafficking, and decreased synaptic strength in prefrontal cortex-responding NAc shell neurons (Pitchers et al., 2012). Finally, periods of abstinence from sexual experience were found to be critical for enhanced Amph reward, NAc spinogenesis (Pitchers et al., 2010a), and glutamate receptor trafficking (Pitchers et al., 2012). These findings suggest that natural and drug reward experiences share common mechanisms of neural plasticity}}{{cite journal | vauthors = Beloate LN, Weems PW, Casey GR, Webb IC, Coolen LM | title = Nucleus accumbens NMDA receptor activation regulates amphetamine cross-sensitization and deltaFosB expression following sexual experience in male rats | journal = Neuropharmacology | volume = 101 | pages = 154–64 | date = February 2016 | pmid = 26391065 | doi = 10.1016/j.neuropharm.2015.09.023 | s2cid = 25317397 }} This phenomenon is notable since, in humans, a dopamine dysregulation syndrome, characterized by drug-induced compulsive engagement in natural rewards (specifically, sexual activity, shopping, and gambling), has been observed in some individuals taking dopaminergic medications.

ΔFosB inhibitors (drugs or treatments that oppose its action) may be an effective treatment for addiction and addictive disorders.{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2009 | publisher = McGraw-Hill Medical | location = New York | isbn = 978-0-07-148127-4 | pages = 384–85 | edition = 2nd | chapter = Chapter 15: Reinforcement and addictive disorders }}

The release of dopamine in the nucleus accumbens plays a role in the reinforcing qualities of many forms of stimuli, including naturally reinforcing stimuli like palatable food and sex.{{cite journal | vauthors = Salamone JD | title = Complex motor and sensorimotor functions of striatal and accumbens dopamine: involvement in instrumental behavior processes | journal = Psychopharmacology | volume = 107 | issue = 2–3 | pages = 160–74 | year = 1992 | pmid = 1615120 | doi = 10.1007/bf02245133 | s2cid = 30545845 }}{{cite journal | vauthors = Kauer JA, Malenka RC | title = Synaptic plasticity and addiction | journal = Nature Reviews. Neuroscience | volume = 8 | issue = 11 | pages = 844–58 | date = November 2007 | pmid = 17948030 | doi = 10.1038/nrn2234 | s2cid = 38811195 | doi-access = free }} Altered dopamine neurotransmission is frequently observed following the development of an addictive state. In humans and lab animals that have developed an addiction, alterations in dopamine or opioid neurotransmission in the nucleus accumbens and other parts of the striatum are evident. Use of certain drugs (e.g., cocaine) affect cholinergic neurons that innervate the reward system, in turn affecting dopamine signaling in this region.{{cite journal | vauthors = Witten IB, Lin SC, Brodsky M, Prakash R, Diester I, Anikeeva P, Gradinaru V, Ramakrishnan C, Deisseroth K | title = Cholinergic interneurons control local circuit activity and cocaine conditioning | journal = Science | volume = 330 | issue = 6011 | pages = 1677–81 | date = December 2010 | pmid = 21164015 | pmc = 3142356 | doi = 10.1126/science.1193771 | bibcode = 2010Sci...330.1677W }}

A recent study in Addiction reports that GLP-1 agonist medications, such as semaglutide, which are commonly used for diabetes and weight management, may also reduce the risk of overdose and alcohol intoxication in people with substance use disorders.{{Cite journal |last1=Qeadan |first1=Fares |last2=McCunn |first2=Ashlie |last3=Tingey |first3=Benjamin |date=2024-10-16 |title=The association between glucose-dependent insulinotropic polypeptide and/or glucagon-like peptide-1 receptor agonist prescriptions and substance-related outcomes in patients with opioid and alcohol use disorders: A real-world data analysis |journal=Addiction |volume=120 |issue=2 |pages=236–250 |language=en |doi=10.1111/add.16679 |issn=0965-2140|doi-access=free |pmid=39415416 |pmc=11707322 }} The study analyzed nearly nine years of health records from 1.3 million individuals across 136 U.S. hospitals, including 500,000 with opioid use disorder and over 800,000 with alcohol use disorder.{{Cite web |last=Shareef |first=Faizah |title=Weight loss drugs like Ozempic may help reduce overdose risks: Study |url=https://abcnews.go.com/Health/weight-loss-drugs-ozempic-reduce-overdose-risks-study/story?id=114875203 |access-date=2024-10-18 |website=ABC News |language=en}} Researchers found that those who used Ozempic or similar medications had a 40% lower risk of opioid overdose and a 50% lower risk of alcohol intoxication compared to those not using these drugs.

{{main|Reward system}}

{{Annotated image 4

| caption = Top: this depicts the initial effects of high dose exposure to an addictive drug on gene expression in the nucleus accumbens for various Fos family proteins (i.e., c-Fos, FosB, ΔFosB, Fra1, and Fra2).
Bottom: this illustrates the progressive increase in ΔFosB expression in the nucleus accumbens following repeated twice daily drug binges, where these phosphorylated (35–37 kilodalton) ΔFosB isoforms persist in the D1-type medium spiny neurons of the nucleus accumbens for up to 2 months.{{cite journal |vauthors=Nestler EJ, Barrot M, Self DW | title = DeltaFosB: a sustained molecular switch for addiction | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 98 | issue = 20 | pages = 11042–46 |date=September 2001 | pmid = 11572966 | pmc = 58680 | doi = 10.1073/pnas.191352698 | quote = Although the ΔFosB signal is relatively long-lived, it is not permanent. ΔFosB degrades gradually and can no longer be detected in [the] brain after 1–2 months of drug withdrawal ... Indeed, ΔFosB is the longest-lived adaptation known to occur in [the] adult brain, not only in response to drugs of abuse, but to any other perturbation (that doesn't involve lesions) as well. | bibcode = 2001PNAS...9811042N | doi-access = free }}

| header = ΔFosB accumulation from excessive drug use

| header_background = light-dark(aliceblue,var(--background-color-neutral))

| alt = ΔFosB accumulation graph

| image = ΔFosB accumulation.svg

| class = skin-invert-image

| image-bg-color = light-dark(white,transparent)

| annot-color = var(--color-base,#202122)

| align = right

| icon = none

| image-width = 400

| image-left = 0

| image-top = 0

| width = 400

| height = 440

| annotations =

}}

Understanding the pathways in which drugs act and how drugs can alter those pathways is key when examining the biological basis of drug addiction. The reward pathway, known as the mesolimbic pathway, or its extension, the mesocorticolimbic pathway, is characterized by the interaction of several areas of the brain.

• The projections from the ventral tegmental area (VTA) are a network of dopaminergic neurons with co-localized postsynaptic glutamate receptors (AMPAR and NMDAR). These cells respond when stimuli indicative of a reward are present. The VTA supports learning and sensitization development and releases dopamine (DA) into the forebrain.{{cite journal |vauthors=Jones S, Bonci A |title=Synaptic plasticity and drug addiction |journal=Current Opinion in Pharmacology |volume=5 |issue=1 |pages=20–25 |year=2005 |pmid=15661621 |doi=10.1016/j.coph.2004.08.011}} These neurons project and release DA into the nucleus accumbens,{{cite journal |vauthors=Eisch AJ, Harburg GC |title=Opiates, psychostimulants, and adult hippocampal neurogenesis: Insights for addiction and stem cell biology |journal=Hippocampus |volume=16 |issue=3 |pages=271–86 |year=2006 |pmid=16411230 |doi=10.1002/hipo.20161|s2cid=23667629 }} through the mesolimbic pathway. Virtually all drugs causing drug addiction increase the DA release in the mesolimbic pathway.{{cite book | vauthors = Rang HP |title=Pharmacology |publisher=Churchill Livingstone |location=Edinburgh |year=2003 |page=596 |isbn=978-0-443-07145-4}}
• The nucleus accumbens (NAcc) is one output of the VTA projections. The nucleus accumbens itself consists mainly of GABAergic medium spiny neurons (MSNs).{{cite journal |vauthors=Kourrich S, Rothwell PE, Klug JR, Thomas MJ |title=Cocaine experience controls bidirectional synaptic plasticity in the nucleus accumbens |journal=J. Neurosci. |volume=27 |issue=30 |pages=7921–28 |year=2007 |pmid=17652583 |pmc=6672735 |doi=10.1523/JNEUROSCI.1859-07.2007}} The NAcc is associated with acquiring and eliciting conditioned behaviors, and is involved in the increased sensitivity to drugs as addiction progresses. Overexpression of ΔFosB in the nucleus accumbens is a necessary common factor in essentially all known forms of addiction; ΔFosB is a strong positive modulator of positively reinforced behaviors.
• The prefrontal cortex, including the anterior cingulate and orbitofrontal cortices,{{cite journal | vauthors = Kalivas PW, Volkow ND | title = The neural basis of addiction: a pathology of motivation and choice | journal = The American Journal of Psychiatry | volume = 162 | issue = 8 | pages = 1403–13 | date = August 2005 | pmid = 16055761 | doi = 10.1176/appi.ajp.162.8.1403 }} is another VTA output in the mesocorticolimbic pathway; it is important for the integration of information which helps determine whether a behavior will be elicited.{{cite journal | vauthors = Floresco SB, Ghods-Sharifi S | title = Amygdala-prefrontal cortical circuitry regulates effort-based decision making | journal = Cerebral Cortex | volume = 17 | issue = 2 | pages = 251–60 | date = February 2007 | pmid = 16495432 | doi = 10.1093/cercor/bhj143 | citeseerx = 10.1.1.335.4681 }} It is critical for forming associations between the rewarding experience of drug use and cues in the environment. Importantly, these cues are strong mediators of drug-seeking behavior and can trigger relapse even after months or years of abstinence.{{cite journal | vauthors = Perry CJ, Zbukvic I, Kim JH, Lawrence AJ | title = Role of cues and contexts on drug-seeking behaviour | journal = British Journal of Pharmacology | volume = 171 | issue = 20 | pages = 4636–72 | date = October 2014 | pmid = 24749941 | pmc = 4209936 | doi = 10.1111/bph.12735 }}

Other brain structures that are involved in addiction include:

• The basolateral amygdala projects into the NAcc and is thought to be important for motivation.
• The hippocampus is involved in drug addiction, because of its role in learning and memory. Much of this evidence stems from investigations showing that manipulating cells in the hippocampus alters DA levels in NAcc and firing rates of VTA dopaminergic cells.

Dopamine is the primary neurotransmitter of the reward system in the brain. It plays a role in regulating movement, emotion, cognition, motivation, and feelings of pleasure.{{cite journal | vauthors = Volkow ND, Fowler JS, Wang GJ, Swanson JM, Telang F | title = Dopamine in drug abuse and addiction: results of imaging studies and treatment implications | journal = Arch. Neurol. | volume = 64 | issue = 11 | pages = 1575–79 | year = 2007 | pmid = 17998440 | doi = 10.1001/archneur.64.11.1575 | doi-access = free }} Natural rewards, like eating, as well as recreational drug use cause a release of dopamine, and are associated with the reinforcing nature of these stimuli.{{cite web|url=http://www.drugabuse.gov/publications/science-addiction/drugs-brain|title=Drugs, Brains, and Behavior: The Science of Addiction|date=6 July 2020 |publisher=National Institute on Drug Abuse}} Nearly all addictive drugs, directly or indirectly, act on the brain's reward system by heightening dopaminergic activity.{{cite web|url=http://www.drugabuse.gov/infofacts/understand.html|title=Understanding Drug Abuse and Addiction|publisher=National Institute on Drug Abuse|date=November 2012|access-date=12 February 2015|archive-date=16 August 2011|archive-url=https://web.archive.org/web/20110816044828/http://www.drugabuse.gov/infofacts/understand.html|url-status=dead}}

Excessive intake of many types of addictive drugs results in repeated release of high amounts of dopamine, which in turn affects the reward pathway directly through heightened dopamine receptor activation. Prolonged and abnormally high levels of dopamine in the synaptic cleft can induce receptor downregulation in the neural pathway. Downregulation of mesolimbic dopamine receptors can result in a decrease in the sensitivity to natural reinforcers.

Drug seeking behavior is induced by glutamatergic projections from the prefrontal cortex to the nucleus accumbens. This idea is supported with data from experiments showing that drug seeking behavior can be prevented following the inhibition of AMPA glutamate receptors and glutamate release in the nucleus accumbens.

===Reward sensitization{{anchor|Sensitization|Drug sensitization}}===

Reward sensitization is a process that causes an increase in the amount of reward (specifically, incentive salience{{#tag:ref|Incentive salience, the "motivational salience" for a reward, is a "desire" or "want" attribute, which includes a motivational component, that the brain assigns to a rewarding stimulus. As a consequence, incentive salience acts as a motivational "magnet" for a rewarding stimulus that commands attention, induces approach, and causes the rewarding stimulus to be sought out.{{cite journal | vauthors = Berridge KC | title = From prediction error to incentive salience: mesolimbic computation of reward motivation | journal = Eur. J. Neurosci. | volume = 35 | issue = 7 | pages = 1124–43 | date = April 2012 | pmid = 22487042 | pmc = 3325516 | doi = 10.1111/j.1460-9568.2012.07990.x | quote = Here I discuss how mesocorticolimbic mechanisms generate the motivation component of incentive salience. Incentive salience takes Pavlovian learning and memory as one input and as an equally important input takes neurobiological state factors (e.g. drug states, appetite states, satiety states) that can vary independently of learning. Neurobiological state changes can produce unlearned fluctuations or even reversals in the ability of a previously learned reward cue to trigger motivation. Such fluctuations in cue-triggered motivation can dramatically depart from all previously learned values about the associated reward outcome. ... Associative learning and prediction are important contributors to motivation for rewards. Learning gives incentive value to arbitrary cues such as a Pavlovian conditioned stimulus (CS) that is associated with a reward (unconditioned stimulus or UCS). Learned cues for reward are often potent triggers of desires. For example, learned cues can trigger normal appetites in everyone, and can sometimes trigger compulsive urges and relapse in individuals with addictions.
Cue-triggered 'wanting' for the UCS
A brief CS encounter (or brief UCS encounter) often primes a pulse of elevated motivation to obtain and consume more reward UCS. This is a signature feature of incentive salience.
Cue as attractive motivational magnets
When a Pavlovian CS+ is attributed with incentive salience it not only triggers 'wanting' for its UCS, but often the cue itself becomes highly attractive – even to an irrational degree. This cue attraction is another signature feature of incentive salience ... Two recognizable features of incentive salience are often visible that can be used in neuroscience experiments: (i) UCS-directed 'wanting' – CS-triggered pulses of intensified 'wanting' for the UCS reward; and (ii) CS-directed 'wanting' – motivated attraction to the Pavlovian cue, which makes the arbitrary CS stimulus into a motivational magnet.}}|group="note"}}) that is assigned by the brain to a rewarding stimulus (e.g., a drug). In simple terms, when reward sensitization to a specific stimulus (e.g., a drug) occurs, an individual's "wanting" or desire for the stimulus itself and its associated cues increases.{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2009 | publisher = McGraw-Hill Medical | location = New York | isbn = 978-0-07-148127-4 | pages = 147–48, 366–67, 375–76 | edition = second | quote= VTA DA neurons play a critical role in motivation, reward-related behavior (Chapter 15), attention, and multiple forms of memory. This organization of the DA system, wide projection from a limited number of cell bodies, permits coordinated responses to potent new rewards. Thus, acting in diverse terminal fields, dopamine confers motivational salience ("wanting") on the reward itself or associated cues (nucleus accumbens shell region), updates the value placed on different goals in light of this new experience (orbital prefrontal cortex), helps consolidate multiple forms of memory (amygdala and hippocampus), and encodes new motor programs that will facilitate obtaining this reward in the future (nucleus accumbens core region and dorsal striatum). In this example, dopamine modulates the processing of sensorimotor information in diverse neural circuits to maximize the ability of the organism to obtain future rewards. ...
The brain reward circuitry that is targeted by addictive drugs normally mediates the pleasure and strengthening of behaviors associated with natural reinforcers, such as food, water, and sexual contact. Dopamine neurons in the VTA are activated by food and water, and dopamine release in the NAc is stimulated by the presence of natural reinforcers, such as food, water, or a sexual partner. ...
The NAc and VTA are central components of the circuitry underlying reward and memory of reward. As previously mentioned, the activity of dopaminergic neurons in the VTA appears to be linked to reward prediction. The NAc is involved in learning associated with reinforcement and the modulation of motoric responses to stimuli that satisfy internal homeostatic needs. The shell of the NAc appears to be particularly important to initial drug actions within reward circuitry; addictive drugs appear to have a greater effect on dopamine release in the shell than in the core of the NAc. ... If motivational drive is described in terms of wanting, and hedonic evaluation in terms of liking, it appears that wanting can be dissociated from liking and that dopamine may influence these phenomena differently. Differences between wanting and liking are confirmed in reports by humans with addictions, who state that their desire for drugs (wanting) increases with continued use even when pleasure (liking) decreases because of tolerance.}} Reward sensitization normally occurs following chronically high levels of exposure to the stimulus. ΔFosB expression in D1-type medium spiny neurons in the nucleus accumbens has been shown to directly and positively regulate reward sensitization involving drugs and natural rewards.

"Cue-induced wanting" or "cue-triggered wanting", a form of craving that occurs in addiction, is responsible for most of the compulsive behavior that people with addictions exhibit.{{cite book |doi=10.1016/bs.pbr.2015.07.005 |chapter=Reinforcement principles for addiction medicine; from recreational drug use to psychiatric disorder |title=Neuroscience for Addiction Medicine: From Prevention to Rehabilitation - Constructs and Drugs |series=Progress in Brain Research |year=2016 | vauthors = Edwards S |volume=223 |pages=63–76 |pmid=26806771 |isbn=978-0-444-63545-7 |quote=An important dimension of reinforcement highly relevant to the addiction process (and particularly relapse) is secondary reinforcement (Stewart, 1992). Secondary reinforcers (in many cases also considered conditioned reinforcers) likely drive the majority of reinforcement processes in humans. In the specific case of drug addiction, cues and contexts that are intimately and repeatedly associated with drug use will themselves become reinforcing ... A fundamental piece of Robinson and Berridge's incentive-sensitization theory of addiction posits that the incentive value or attractive nature of such secondary reinforcement processes, in addition to the primary reinforcers themselves, may persist and even become sensitized over time in league with the development of drug addiction (Robinson and Berridge, 1993).}} During the development of an addiction, the repeated association of otherwise neutral and even non-rewarding stimuli with drug consumption triggers an associative learning process that causes these previously neutral stimuli to act as conditioned positive reinforcers of addictive drug use (i.e., these stimuli start to function as drug cues).{{cite journal | vauthors = Berridge KC, Kringelbach ML | title = Pleasure systems in the brain | journal = Neuron | volume = 86 | issue = 3 | pages = 646–664 | date = May 2015 | pmid = 25950633 | pmc = 4425246 | doi = 10.1016/j.neuron.2015.02.018 }} As conditioned positive reinforcers of drug use, these previously neutral stimuli are assigned incentive salience (which manifests as a craving) – sometimes at pathologically high levels due to reward sensitization – which can transfer to the primary reinforcer (e.g., the use of an addictive drug) with which it was originally paired.

Research on the interaction between natural and drug rewards suggests that dopaminergic psychostimulants (e.g., amphetamine) and sexual behavior act on similar biomolecular mechanisms to induce ΔFosB in the nucleus accumbens and possess a bidirectional reward cross-sensitization effect{{#tag:ref|In simplest terms, this means that when either amphetamine or sex is perceived as more alluring or desirable through reward sensitization, this effect occurs with the other as well.|group="note"}} that is mediated through ΔFosB. In contrast to ΔFosB's reward-sensitizing effect, CREB transcriptional activity decreases user's sensitivity to the rewarding effects of the substance. CREB transcription in the nucleus accumbens is implicated in psychological dependence and symptoms involving a lack of pleasure or motivation during drug withdrawal.

{{Clear}}

{{Addiction-related plasticity|title=Summary of addiction-related plasticity}}

{{Clear}}

{{Further|Neuroepigenetics|Chromatin remodeling}}

Altered epigenetic regulation of gene expression within the brain's reward system plays a significant and complex role in the development of drug addiction.{{cite journal | vauthors = Walker DM, Cates HM, Heller EA, Nestler EJ | title = Regulation of chromatin states by drugs of abuse | journal = Curr. Opin. Neurobiol. | volume = 30 | pages = 112–21 | date = February 2015 | pmid = 25486626 | doi = 10.1016/j.conb.2014.11.002 | quote = Studies investigating general HDAC inhibition on behavioral outcomes have produced varying results but it seems that the effects are specific to the timing of exposure (either before, during or after exposure to drugs of abuse) as well as the length of exposure | pmc=4293340}} Addictive drugs are associated with three types of epigenetic modifications within neurons. These are (1) histone modifications, (2) epigenetic methylation of DNA at CpG sites at (or adjacent to) particular genes, and (3) epigenetic downregulation or upregulation of microRNAs which have particular target genes. As an example, while hundreds of genes in the cells of the nucleus accumbens (NAc) exhibit histone modifications following drug exposure – particularly, altered acetylation and methylation states of histone residues – most other genes in the NAc cells do not show such changes.

{{Further|Substance use disorder#Diagnosis|Problem gambling#Diagnosis}}

The fifth edition of the DSM uses the term substance use disorder to refer to a spectrum of drug use-related disorders. The DSM-5 eliminates the terms abuse and dependence from diagnostic categories, instead using the specifiers of mild, moderate and severe to indicate the extent of disordered use. These specifiers are determined by the number of diagnostic criteria present in a given case. In the DSM-5, the term drug addiction is synonymous with severe substance use disorder.{{cite web | title=Facing Addiction in America: The Surgeon General's Report on Alcohol, Drugs, and Health | url=https://addiction.surgeongeneral.gov/sites/default/files/surgeon-generals-report.pdf | website = Office of the Surgeon General | publisher=US Department of Health and Human Services | date=November 2016 | access-date=28 January 2017 | pages = 35–37, 45, 63, 155, 317, 338 }}

The DSM-5 introduced a new diagnostic category for behavioral addictions. Problem gambling is the only condition included in this category in the fifth edition.{{cite web |author=American Psychiatric Association |date=2013 |title=Substance-Related and Addictive Disorders |url=http://www.dsm5.org/documents/substance%20use%20disorder%20fact%20sheet.pdf |url-status=dead |archive-url=https://web.archive.org/web/20150815050402/http://www.dsm5.org/Documents/Substance%20Use%20Disorder%20Fact%20Sheet.pdf |archive-date=15 August 2015 |access-date=8 April 2023 |publisher=American Psychiatric Publishing |pages=1–2 |quote=Additionally, the diagnosis of dependence caused much confusion. Most people link dependence with "addiction" when in fact dependence can be a normal body response to a substance.}} Internet gaming disorder is listed as a "condition requiring further study" in the DSM-5.{{cite journal | vauthors = Petry NM, Rehbein F, Gentile DA, Lemmens JS, Rumpf HJ, Mößle T, Bischof G, Tao R, Fung DS, Borges G, Auriacombe M, González Ibáñez A, Tam P, O'Brien CP | title = An international consensus for assessing internet gaming disorder using the new DSM-5 approach | journal = Addiction | volume = 109 | issue = 9 | pages = 1399–406 | date = September 2014 | pmid = 24456155 | doi = 10.1111/add.12457 }}

Past editions have used physical dependence and the associated withdrawal syndrome to identify an addictive state. Physical dependence occurs when the body has adjusted by incorporating the substance into its "normal" functioning – i.e., attains homeostasis – and therefore physical withdrawal symptoms occur on cessation of use.{{cite journal |vauthors=Torres G, Horowitz JM | title = Drugs of abuse and brain gene expression | journal = Psychosom Med | volume = 61 | issue = 5 | pages = 630–50 | year = 1999 | pmid = 10511013 | doi = 10.1097/00006842-199909000-00007| citeseerx = 10.1.1.326.4903 }} Tolerance is the process by which the body continually adapts to the substance and requires increasingly larger amounts to achieve the original effects. Withdrawal refers to physical and psychological symptoms experienced when reducing or discontinuing a substance that the body has become dependent on. Symptoms of withdrawal generally include but are not limited to body aches, anxiety, irritability, intense cravings for the substance, dysphoria, nausea, hallucinations, headaches, cold sweats, tremors, and seizures. During acute physical opioid withdrawal, symptoms of restless legs syndrome are common and may be profound. This phenomenon originated the idiom "kicking the habit".

Medical researchers who actively study addiction have criticized the DSM classification of addiction for being flawed and involving arbitrary diagnostic criteria.{{cite book | vauthors = Malenka RC, Nestler EJ, Hyman SE, Holtzman DM | title = Molecular Neuropharmacology: A Foundation for Clinical Neuroscience | year = 2015 | publisher = McGraw-Hill Medical | location = New York | isbn = 978-0-07-182770-6 | edition = 3rd | chapter = Chapter 16: Reinforcement and Addictive Disorders | quote = The official diagnosis of drug addiction by the Diagnostic and Statistic Manual of Mental Disorders (2013), which uses the term substance use disorder, is flawed. Criteria used to make the diagnosis of substance use disorders include tolerance and somatic dependence/withdrawal, even though these processes are not integral to addiction as noted. It is ironic and unfortunate that the manual still avoids use of the term addiction as an official diagnosis, even though addiction provides the best description of the clinical syndrome.}}

The eleventh revision of the International Classification of Diseases, commonly referred to as ICD-11, conceptualizes diagnosis somewhat differently. ICD-11 first distinguishes between problems with psychoactive substance use ("Disorders due to substance use") and behavioral addictions ("Disorders due to addictive behaviours").{{Cite web |date=2023 |title=International Classification of Diseases 11th revision – ICD-11. Disorders due to substance use or addictive behaviours |url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/1602669465 |access-date=10 April 2023 |website=World Health Organization |location=Geneva}} With regard to psychoactive substances, ICD-11 explains that the included substances initially produce "pleasant or appealing psychoactive effects that are rewarding and reinforcing with repeated use, [but] with continued use, many of the included substances have the capacity to produce dependence. They have the potential to cause numerous forms of harm, both to mental and physical health."{{Cite web |title=International Classification of Diseases 11th revision – ICD-11. Disorders due to substance use |url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/590211325 |access-date=24 March 2023 |website=World Health Organization |location=Geneva |date=2023}} Instead of the DSM-5 approach of one diagnosis ("Substance Use Disorder") covering all types of problematic substance use, ICD-11 offers three diagnostic possibilities: 1) Episode of Harmful Psychoactive Substance Use, 2) Harmful Pattern of Psychoactive Substance Use, and 3) Substance Dependence.

The Addictions Neuroclinical Assessment is used to diagnose addiction disorders. This tool measures three different domains: executive function, incentive salience, and negative emotionality.{{cite journal |vauthors=Koob GF, Powell P, White A |date=November 2020 |title=Addiction as a Coping Response: Hyperkatifeia, Deaths of Despair, and COVID-19 |journal=Am J Psychiatry |volume=177 |issue=11 |pages=1031–1037 |doi=10.1176/appi.ajp.2020.20091375 |pmid=33135468 |s2cid=226233515}}{{cite journal |vauthors=Kwako LE, Momenan R, Litten RZ, Koob GF, Goldman D |date=August 2016 |title=Addictions Neuroclinical Assessment: A Neuroscience-Based Framework for Addictive Disorders |journal=Biological Psychiatry |volume=80 |issue=3 |pages=179–189 |doi=10.1016/j.biopsych.2015.10.024 |pmc=4870153 |pmid=26772405}} Executive functioning consists of processes that would be disrupted in addiction. In the context of addiction, incentive salience determines how one perceives the addictive substance. Increased negative emotional responses have been found with individuals with addictions.

This is a screening and assessment tool in one, assessing commonly used substances. This tool allows for a simple diagnosis, eliminating the need for several screening and assessment tools, as it includes both TAPS-1 and TAPS-2, screening and assessment tools respectively. The screening component asks about the frequency of use of the specific substance (tobacco, alcohol, prescription medication, and other).{{Cite web |title=Tobacco, Alcohol, Prescription medication, and other Substance use (TAPS) Tool |url=https://nida.nih.gov/taps2/ |access-date=29 November 2022 |website=nida.nih.gov}} If an individual screens positive, the second component will begin. This dictates the risk level of the substance.

The CRAFFT (Car-Relax-Alone-Forget-Family and Friends-Trouble) is a screening tool that is used in medical centers. The CRAFFT is in version 2.1 and has a version for nicotine and tobacco use called the CRAFFT 2.1+N.{{Cite web |title=About the CRAFFT – CRAFFT |url=https://crafft.org/about-the-crafft/ |access-date=3 December 2022 |language=en-US}} This tool is used to identify substance use, substance related driving risk, and addictions among adolescents. This tool uses a set of questions for different scenarios.{{Cite web |title=Use the CRAFFT – CRAFFT |url=https://crafft.org/use-the-crafft/ |access-date=3 December 2022 |language=en-US}} In the case of a specific combination of answers, different question sets can be used to yield a more accurate answer. After the questions, the DSM-5 criteria are used to identify the likelihood of the person having substance use disorder. After these tests are done, the clinician is to give the "5 RS" of brief counseling.

The five Rs of brief counseling includes:

1. REVIEW screening results
2. RECOMMEND to not use
3. RIDING/DRIVING risk counseling
4. RESPONSE: elicit self-motivational statements
5. REINFORCE self-efficacy

The Drug Abuse Screening Test (DAST) is a self-reporting tool that measures problematic substance use.{{cite journal |vauthors=Yudko E, Lozhkina O, Fouts A |date=March 2007 |title=A comprehensive review of the psychometric properties of the Drug Abuse Screening Test |journal=Journal of Substance Abuse Treatment |volume=32 |issue=2 |pages=189–198 |doi=10.1016/j.jsat.2006.08.002 |pmid=17306727}} Responses to this test are recorded as yes or no answers, and scored as a number between zero and 28. Drug abuse or dependence, are indicated by a cut off score of 6. Three versions of this screening tool are in use: DAST-28, DAST-20, and DAST-10. Each of these instruments are copyrighted by Dr. Harvey A. Skinner.

The Alcohol, Smoking, and Substance Involvement Test (ASSIST) is an interview-based questionnaire consisting of eight questions developed by the WHO.{{cite journal |vauthors=Han BH, Moore AA |date=February 2018 |title=Prevention and Screening of Unhealthy Substance Use by Older Adults |journal=Clinics in Geriatric Medicine |volume=34 |issue=1 |pages=117–129 |doi=10.1016/j.cger.2017.08.005 |pmc=5718360 |pmid=29129212}} The questions ask about lifetime use; frequency of use; urge to use; frequency of health, financial, social, or legal problems related to use; failure to perform duties; if anyone has raised concerns over use; attempts to limit or moderate use; and use by injection.{{cite journal |vauthors=Ali R, Meena S, Eastwood B, Richards I, Marsden J |date=September 2013 |title=Ultra-rapid screening for substance-use disorders: the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST-Lite) |journal=Drug and Alcohol Dependence |volume=132 |issue=1–2 |pages=352–361 |doi=10.1016/j.drugalcdep.2013.03.001 |pmid=23561823}}

{{Main|Harm reduction|Preventive healthcare}}

Abuse or addiction liability is the tendency to use drugs in a non-medical situation. This is typically for euphoria, mood changing, or sedation.{{Cite web|title=Drug abuse liability|url=https://www.cambridgecognition.com/research-areas/drug-abuse-liability-research/|access-date=9 March 2021| work = Cambridge Cognition |language=en}} Abuse liability is used when the person using the drugs wants something that they otherwise can not obtain. The only way to obtain this is through the use of drugs. When looking at abuse liability there are a number of determining factors in whether the drug is abused. These factors are: the chemical makeup of the drug, the effects on the brain, and the age, vulnerability, and the health (mental and physical) of the population being studied. There are a few drugs with a specific chemical makeup that leads to a high abuse liability. These are: cocaine, heroin, inhalants, marijuana, MDMA (ecstasy), methamphetamine, PCP, synthetic cannabinoids, synthetic cathinones (bath salts), nicotine (e.g. tobacco), and alcohol.{{Cite web | author = National Institute on Drug Abuse |date=20 August 2020|title=Commonly Used Drugs Charts|url=https://www.drugabuse.gov/drug-topics/commonly-used-drugs-charts|access-date=9 March 2021|website=National Institute on Drug Abuse|language=en}}

Vaccines for addiction have been investigated as a possibility since the early 2000s.{{Cite book|url=https://www.ncbi.nlm.nih.gov/sites/books/NBK24623/|title=Vaccines and Immunotherapies to Control Addiction in Minors: The Legal Framework|first1=Henrick J.|last1=Harwood|first2=Tracy G.|last2=Myers|first3=National Research Council (US) and Institute of Medicine (US) Committee on Immunotherapies and Sustained-Release Formulations for Treating Drug|last3=Addiction|date=July 23, 2004|publisher=National Academies Press (US)|via=National Center for Biotechnology Information }} The general theory of a vaccine intended to "immunize" against drug addiction or other substance abuse is that it would condition the immune system to attack and consume or otherwise disable the molecules of such substances that cause a reaction in the brain, thus preventing the addict from being able to realize the effect of the drug. Addictions that have been floated as targets for such treatment include nicotine, opioids, and fentanyl.{{cite web|url=https://www.scripps.edu/news-and-events/press-room/2020/20200730-janda-heroinvaccine.html |title='Heavy' heroin vaccine provides hope for addiction treatment|publisher=Scripps Research|date=July 30, 2020}}{{Cite web|url=https://www.cuimc.columbia.edu/news/experimental-opioid-vaccine-being-tested-columbia|title=Experimental Opioid Vaccine Being Tested at Columbia|date=July 1, 2021|website=Columbia University Irving Medical Center}}{{Cite web|url=https://www.seattletimes.com/seattle-news/mental-health/to-fight-opioid-crisis-uw-researchers-take-new-shot-at-developing-vaccine-against-addictive-drugs/|title=To fight opioid crisis, UW researchers take new shot at developing vaccine against addictive drugs|first1=Hannah|last1=Furfaro|date=January 5, 2022|website=The Seattle Times}}{{Cite web|url=https://www.addictioncenter.com/news/2022/01/vaccine-against-addiction/|title=A Vaccine Against Addiction|website=Addiction Center|date=12 January 2022 }} Vaccines have been identified as potentially being more effective than other anti-addiction treatments, due to "the long duration of action, the certainty of administration and a potential reduction of toxicity to important organs".{{Cite web|url=https://drugabuse.com/blog/why-dont-we-have-addiction-vaccines/|title=Why Don't We Have Addiction Vaccines?|author=American Addiction Centers Editorial Staff|orig-date=December 29, 2016|date=January 4, 2022|website=DrugAbuse.com}}

Specific addiction vaccines in development include:

• NicVAX, a conjugate vaccine intended to reduce or eliminate physical dependence on nicotine.{{cite web|url=http://www.drugabuse.gov/NIDA_Notes/NNVol15N5/Vaccine.html |title=Nicotine Vaccine Moves Toward Clinical Trials |author=Barbara Shine |publisher=National Institute on Drug Abuse |date=October 2000 |access-date=2006-09-19 |archive-url=https://web.archive.org/web/20060810101935/http://www.drugabuse.gov/NIDA_Notes/NNVol15N5/Vaccine.html |archive-date=2006-08-10 |url-status=dead }} This proprietary vaccine is being developed by Nabi Biopharmaceuticals{{cite web | url=http://www.nabi.com | title = Nabi Biopharmaceuticals Website}} of Rockville, MD. with the support from the U.S. National Institute on Drug Abuse. NicVAX consists of the hapten 3'-aminomethylnicotine which has been conjugated (attached) to Pseudomonas aeruginosa exotoxin A.{{cite journal | last = Hatsukami | first = Dorothy K. | author-link = Dorothy Hatsukami|author2=Rennard S |author3=Jorenby D |author4=Fiore M |author5=Koopmeiners J |author6=de Vos A |author7=Horwith G |author8=Pentel PR | title = Safety and immunogenicity of a nicotine conjugate vaccine in current smokers | journal = Clinical Pharmacology & Therapeutics | volume = 78 | issue = 5 | pages = 456–467 |year= 2005 | doi = 10.1016/j.clpt.2005.08.007 | pmid = 16321612 | s2cid = 1218556 }}
• TA-CD, an active vaccine{{cite journal |vauthors=Martell BA, Mitchell E, Poling J, Gonsai K, Kosten TR |title=Vaccine pharmacotherapy for the treatment of cocaine dependence |journal=Biol. Psychiatry |volume=58 |issue=2 |pages=158–64 |date=July 2005 |pmid=16038686 |doi=10.1016/j.biopsych.2005.04.032 |s2cid=22415520 }} developed by the Xenova Group which is used to negate the effects of cocaine. It is created by combining norcocaine with inactivated cholera toxin. It works in much the same way as a regular vaccine. A large protein molecule attaches to cocaine, which stimulates response from antibodies, which destroy the molecule. This also prevents the cocaine from crossing the blood–brain barrier, negating the euphoric high and rewarding effect of cocaine caused from stimulation of dopamine release in the mesolimbic reward pathway. The vaccine does not affect the user's "desire" for cocaine—only the physical effects of the drug.{{cite web |url=http://news.bbc.co.uk/2/hi/health/3804741.stm |title=Cocaine vaccine 'stops addiction' |access-date=2009-10-07|work=BBC News |date=14 June 2004 }}
• TA-NIC, used to create human antibodies to destroy nicotine in the human body so that it is no longer effective.{{Cite web |url=http://www.celticpharma.com/theportfolio/ta-nic.html |title=CelticPharma: TA-NIC Nicotine Dependence. |access-date=2009-10-27 |archive-url=https://web.archive.org/web/20091206100218/http://www.celticpharma.com/theportfolio/ta-nic.html |archive-date=2009-12-06 |url-status=dead }}

As of September 2023, it was further reported that a vaccine "has been tested against heroin and fentanyl and is on its way to being tested against OxyContin".{{cite news|url=https://www.kiro7.com/news/local/uw-researcher-explains-new-vaccine-being-made-prevent-opioid-overdoses/HXFQ3AZ2YBAGDIELRDIGKCWN6M/ |title=UW researcher explains new vaccine in the works to prevent opioid overdoses |work=KIRO 7|date=September 19, 2023}}

{{Main|Treatment and management of addiction}}

To be effective, treatment for addiction that is pharmacological or biologically based need to be accompanied by other interventions such as cognitive behavioral therapy (CBT) and dialectical behavioral therapy (DBT);individual and group psychotherapy, behavior modification strategies, twelve-step programs, and residential treatment facilities.{{cite journal | vauthors = Taylor SB, Lewis CR, Olive MF | title = The neurocircuitry of illicit psychostimulant addiction: acute and chronic effects in humans | journal = Subst. Abuse Rehabil. | volume = 4 | pages = 29–43 | date = February 2013 | pmid = 24648786 | pmc = 3931688 | doi = 10.2147/SAR.S39684 | quote = Initial drug use can be attributed to the ability of the drug to act as a reward (ie, a pleasurable emotional state or positive reinforcer), which can lead to repeated drug use and dependence.^8,9 A great deal of research has focused on the molecular and neuroanatomical mechanisms of the initial rewarding or reinforcing effect of drugs of abuse. ... At present, no pharmacological therapy has been approved by the FDA to treat psychostimulant addiction. Many drugs have been tested, but none have shown conclusive efficacy with tolerable side effects in humans.¹⁷² ... A new emphasis on larger-scale biomarker, genetic, and epigenetic research focused on the molecular targets of mental disorders has been recently advocated.²¹² In addition, the integration of cognitive and behavioral modification of circuit-wide neuroplasticity (i.e., computer-based training to enhance executive function) may prove to be an effective adjunct-treatment approach for addiction, particularly when combined with cognitive enhancers.^{198,213–216} Furthermore, in order to be effective, all pharmacological or biologically based treatments for addiction need to be integrated into other established forms of addiction rehabilitation, such as CBT, individual and group psychotherapy, behavior-modification strategies, twelve-step programs, and residential treatment facilities. | doi-access = free }} The transtheoretical model (TTM) can be used to determine when treatment can begin and which method will be most effective. If treatment begins too early, it can cause a person to become defensive and resistant to change.{{Cite journal |last=Scott |first=Cynthia G. |date=July 2000 |title=Ethical Issues in Addiction Counseling |url=http://journals.sagepub.com/doi/10.1177/003435520004300405 |journal=Rehabilitation Counseling Bulletin |language=en |volume=43 |issue=4 |pages=209–214 |doi=10.1177/003435520004300405 |pmid=15714702 |s2cid=28556555 |issn=0034-3552}}

{{Further|Countries by alcohol consumption|Opioid epidemic|Prevalence of tobacco use}}

Due to cultural variations, the proportion of individuals who develop a drug or behavioral addiction within a specified time period (i.e., the prevalence) varies over time, by country, and across national population demographics (e.g., by age group, socioeconomic status, etc.). Where addiction is viewed as unacceptable, there will be fewer people addicted.

The prevalence of alcohol dependence is not as high as is seen in other regions. In Asia, not only socioeconomic factors but biological factors influence drinking behavior.{{cite journal | vauthors = Chen CC, Yin SJ | title = Alcohol abuse and related factors in Asia | journal = International Review of Psychiatry | volume = 20 | issue = 5 | pages = 425–433 | date = October 2008 | pmid = 19012127 | doi = 10.1080/09540260802344075 | s2cid = 24571763 }}

Internet addiction disorder is highest in the Philippines, according to both the IAT (Internet Addiction Test) – 5% and the CIAS-R (Revised Chen Internet Addiction Scale) – 21%.{{cite journal | vauthors = Mak KK, Lai CM, Watanabe H, Kim DI, Bahar N, Ramos M, Young KS, Ho RC, Aum NR, Cheng C | title = Epidemiology of internet behaviors and addiction among adolescents in six Asian countries | journal = Cyberpsychology, Behavior and Social Networking | volume = 17 | issue = 11 | pages = 720–728 | date = November 2014 | pmid = 25405785 | doi = 10.1089/cyber.2014.0139 }}

{{Further|Alcoholism in rural Australia}}

The prevalence of substance use disorder among Australians was reported at 5.1% in 2009.{{Cite web | vauthors = Slade T, Johnston A, Teesson M, Whiteford H, Burgess P, Pirkis J, Saw S | author-link3= Maree Teesson | title = The Mental Health of Australians 2: Substance Use Disorders in Australia | publisher = Department of Health and Ageing, Canberra | date = May 2009 | url = https://www.health.gov.au/internet/main/publishing.nsf/Content/A24556C814804A99CA257BF0001CAC45/$File/mha26.pdf }} In 2019 the Australian Institute of Health and Welfare conducted a national drug survey that quantified drug use for various types of drugs and demographics.{{Cite report |url=https://www.aihw.gov.au/reports/illicit-use-of-drugs/national-drug-strategy-household-survey-2019/contents/table-of-contents |title=National Drug Strategy Household Survey 2019 |last=Australian Institute of Health and Welfare (AIHW) |date=2020 |doi=10.25816/E42P-A447 |language=en}} The survey found that in 2019, 11% of people over 14 years old smoke daily; that 9.9% of those who drink alcohol, which equates to 7.5% of the total population age 14 or older, may qualify as alcohol dependent; that 17.5% of the 2.4 million people who used cannabis in the last year may have hazardous use or a dependence problem; and that 63.5% of about 300000 recent users of meth and amphetamines were at risk for developing problem use.

{{Further|Alcoholism in Ireland|Alcoholism in Russia}}

In 2015, the estimated prevalence among the adult population was 18.4% for heavy episodic alcohol use (in the past 30 days); 15.2% for daily tobacco smoking; and 3.8% for cannabis use, 0.77% for amphetamine use, 0.37% for opioid use, and 0.35% for cocaine use in 2017. The mortality rates for alcohol and illicit drugs were highest in Eastern Europe.{{cite journal | vauthors = Peacock A, Leung J, Larney S, Colledge S, Hickman M, Rehm J, Giovino GA, West R, Hall W, Griffiths P, Ali R, Gowing L, Marsden J, Ferrari AJ, Grebely J, Farrell M, Degenhardt L | title = Global statistics on alcohol, tobacco and illicit drug use: 2017 status report | journal = Addiction | volume = 113 | issue = 10 | pages = 1905–1926 | date = October 2018 | pmid = 29749059 | doi = 10.1111/add.14234 | hdl = 11343/283940 | s2cid = 13674349 | url = https://discovery.ucl.ac.uk/id/eprint/10049286/ | doi-access = free | hdl-access = free }} Data shows a downward trend of alcohol use among children 15 years old in most European countries between 2002 and 2014. First-time alcohol use before the age of 13 was recorded for 28% of European children in 2014.{{cite journal | vauthors = Skylstad V, Babirye JN, Kiguli J, Solheim Skar AM, et al. | title = Are we overlooking alcohol use by younger children? | journal = BMJ Paediatrics Open | date = March 2022 | volume = 6 | issue = 1 | page = e001242 | doi = 10.1136/bmjpo-2021-001242 | pmid = 36053657 | pmc = 8905875 }}

{{Further|Cocaine in the United States|Crack epidemic in the United States|Opioid epidemic in the United States}}

Based on representative samples of the US youth population in {{As of|2011|bare=y}}, the lifetime prevalence{{#tag:ref|The lifetime prevalence of an addiction is the percentage of individuals in a population that developed an addiction at some point in their life.|group="note"}} of addictions to alcohol and illicit drugs has been estimated to be approximately 8% and 2–3% respectively.{{cite journal |vauthors=Merikangas KR, McClair VL |date=June 2012 |title=Epidemiology of Substance Use Disorders |journal=Hum. Genet. |volume=131 |issue=6 |pages=779–89 |doi=10.1007/s00439-012-1168-0 |pmc=4408274 |pmid=22543841}} Based on representative samples of the US adult population in {{As of|2011|bare=y}}, the 12-month prevalence of alcohol and illicit drug addictions were estimated at 12% and 2–3% respectively. The lifetime prevalence of prescription drug addictions is around 4.7%.{{cite journal | vauthors = Manubay JM, Muchow C, Sullivan MA | title = Prescription drug abuse: epidemiology, regulatory issues, chronic pain management with narcotic analgesics | journal = Primary Care | volume = 38 | issue = 1 | pages = 71–90 | date = March 2011 | pmid = 21356422 | pmc = 3328297 | doi = 10.1016/j.pop.2010.11.006 }}

{{As of|2021|post=,}} 43.7 million people aged 12 or older surveyed by the National Survey on Drug Use and Health in the United States needed treatment for an addiction to alcohol, nicotine, or other drugs. The groups with the highest number of people were 18–25 years (25.1%) and "American Indian or Alaska Native" (28.7%).{{cite report |vauthors=((Substance Abuse and Mental Health Services Administration)) |date=2022 |title=Key substance use and mental health indicators in the United States: Results from the 2021 National Survey on Drug Use and Health |url=https://www.samhsa.gov/data/report/2021-nsduh-annual-national-report |publisher=Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration |access-date = 24 March 2023 }} Only about 10%, or a little over 2 million, receive any form of treatments, and those that do generally do not receive evidence-based care.{{cite web|title=American Board of Medical Specialties recognizes the new subspecialty of addiction medicine|url=http://www.abam.net/wp-content/uploads/2016/03/1.-News-Release-ADM.pdf|website=American Board of Addiction Medicine|access-date=3 April 2016|date=14 March 2016|quote=Sixteen percent of the non-institutionalized U.S. population age 12 and over – more than 40 million Americans – meets medical criteria for addiction involving nicotine, alcohol or other drugs. This is more than the number of Americans with cancer, diabetes or heart conditions. In 2014, 22.5 million people in the United States needed treatment for addiction involving alcohol or drugs other than nicotine, but only 11.6 percent received any form of inpatient, residential, or outpatient treatment. Of those who do receive treatment, few receive evidence-based care. (There is no information available on how many individuals receive treatment for addiction involving nicotine.)
Risky substance use and untreated addiction account for one-third of inpatient hospital costs and 20 percent of all deaths in the United States each year, and cause or contribute to more than 100 other conditions requiring medical care, as well as vehicular crashes, other fatal and non-fatal injuries, overdose deaths, suicides, homicides, domestic discord, the highest incarceration rate in the world and many other costly social consequences. The economic cost to society is greater than the cost of diabetes and all cancers combined. Despite these startling statistics on the prevalence and costs of addiction, few physicians have been trained to prevent or treat it.|archive-date=21 March 2021|archive-url=https://web.archive.org/web/20210321082744/http://www.abam.net/wp-content/uploads/2016/03/1.-News-Release-ADM.pdf|url-status=dead}}{{cite web|vauthors=Volkow N|title=A Major Step Forward for Addiction Medicine|url=https://www.drugabuse.gov/about-nida/noras-blog/2016/03/major-step-forward-addiction-medicine|website=National Institute on Drug Abuse|publisher=National Institutes of Health|access-date=3 April 2016|date=31 March 2016|quote=Only about 10 percent of the 21 million Americans who meet the need for care for an alcohol or drug use disorder receive any form of treatment, and much of the treatment available does not meet standards for evidence-based care. There are many attitudinal and systemic reasons for this treatment gap, including stigma against treating people with addictions and institutional barriers to providing or funding addiction treatment. ... A major milestone was reached on March 14, 2016, when the American Board of Medical Specialties (ABMS) formally announced recognition of the field of Addiction Medicine as a medical subspecialty. ... In a statement issued to mark this milestone, ABAM President Robert J. Sokol summed up its significance: 'This landmark event, more than any other, recognizes addiction as a preventable and treatable disease, helping to shed the stigma that has long plagued it. It sends a strong message to the public that American medicine is committed to providing expert care for this disease and services designed to prevent the risky substance use that precedes it.'|archive-date=5 April 2016|archive-url=https://web.archive.org/web/20160405133536/https://www.drugabuse.gov/about-nida/noras-blog/2016/03/major-step-forward-addiction-medicine|url-status=dead}} One-third of inpatient hospital costs and 20% of all deaths in the US every year are the result of untreated addictions and risky substance use. In spite of the massive overall economic cost to society, which is greater than the cost of diabetes and all forms of cancer combined, most doctors in the US lack the training to effectively address a drug addiction.

Estimates of lifetime prevalence rates in the US are 1–2% for compulsive gambling, 5% for sexual addiction, 2.8% for food addiction, and 5–6% for compulsive shopping. The time-invariant prevalence rate for sexual addiction and related compulsive sexual behavior (e.g., compulsive masturbation with or without pornography, compulsive cybersex, etc.) within the US ranges from 3–6% of the population.{{cite journal | vauthors = Karila L, Wéry A, Weinstein A, Cottencin O, Petit A, Reynaud M, Billieux J | title = Sexual addiction or hypersexual disorder: different terms for the same problem? A review of the literature | journal = Curr. Pharm. Des. | volume = 20 | issue = 25 | pages = 4012–20 | year = 2014 | pmid = 24001295 | doi = 10.2174/13816128113199990619| s2cid = 19042860 | quote = Sexual addiction, which is also known as hypersexual disorder, has largely been ignored by psychiatrists, even though the condition causes serious psychosocial problems for many people. A lack of empirical evidence on sexual addiction is the result of the disease's complete absence from versions of the Diagnostic and Statistical Manual of Mental Disorders. ... Existing prevalence rates of sexual addiction-related disorders range from 3% to 6%. Sexual addiction/hypersexual disorder is used as an umbrella construct to encompass various types of problematic behaviors, including excessive masturbation, cybersex, pornography use, sexual behavior with consenting adults, telephone sex, strip club visitation, and other behaviors. The adverse consequences of sexual addiction are similar to the consequences of other addictive disorders. Addictive, somatic and psychiatric disorders coexist with sexual addiction. In recent years, research on sexual addiction has proliferated, and screening instruments have increasingly been developed to diagnose or quantify sexual addiction disorders. In our systematic review of the existing measures, 22 questionnaires were identified. As with other behavioral addictions, the appropriate treatment of sexual addiction should combine pharmacological and psychological approaches.}}

According to a 2017 poll conducted by the Pew Research Center, almost half of US adults know a family member or close friend who has struggled with a drug addiction at some point in their life.{{cite web|title=Nearly half of Americans have a family member or close friend who's been addicted to drugs|url=http://www.pewresearch.org/fact-tank/2017/10/26/nearly-half-of-americans-have-a-family-member-or-close-friend-whos-been-addicted-to-drugs/|publisher=Pew Research Center| vauthors = Gramlich J|date=26 October 2017|access-date=14 January 2018}}

In 2019, opioid addiction was acknowledged as a national crisis in the United States.{{cite news |title=We were addicted to their pill, but they were addicted to the money |url=https://www.washingtonpost.com/video/national/we-were-addicted-to-their-pill-but-they-were-addicted-to-the-money/2019/07/21/7c006bc0-4e9b-46a5-bc80-c7e95e46d513_video.html?wpisrc=nl_headlines&wpmm=1 |access-date=22 July 2019 |newspaper=The Washington Post |language=en}} An article in The Washington Post stated that "America's largest drug companies flooded the country with pain pills from 2006 through 2012, even when it became apparent that they were fueling addiction and overdoses."

The National Epidemiologic Survey on Alcohol and Related Conditions found that from 2012 to 2013 the prevalence of Cannabis use disorder in U.S. adults was 2.9%.{{cite journal | vauthors = Hasin DS, Saha TD, Kerridge BT, Goldstein RB, Chou SP, Zhang H, Jung J, Pickering RP, Ruan WJ, Smith SM, Huang B, Grant BF | title = Prevalence of Marijuana Use Disorders in the United States Between 2001–2002 and 2012–2013 | journal = JAMA Psychiatry | volume = 72 | issue = 12 | pages = 1235–1242 | date = December 2015 | pmid = 26502112 | pmc = 5037576 | doi = 10.1001/jamapsychiatry.2015.1858 }}

A Statistics Canada Survey in 2012 found the lifetime prevalence and 12-month prevalence of substance use disorders were 21.6%, and 4.4% in those 15 and older.{{Cite web | publisher = Government of Canada | work = Statistics Canada |date=18 September 2013 |title=Mental and substance use disorders in Canada |url=https://www150.statcan.gc.ca/n1/pub/82-624-x/2013001/article/tbl/tbl1-eng.htm |access-date=8 November 2022 }} Alcohol abuse or dependence reported a lifetime prevalence of 18.1% and a 12-month prevalence of 3.2%. Cannabis abuse or dependence reported a lifetime prevalence of 6.8% and a 12-month prevalence of 3.2%. Other drug abuse or dependence has a lifetime prevalence of 4.0% and a 12-month prevalence of 0.7%. Substance use disorder is a term used interchangeably with a drug addiction.{{Cite news |title=Drug addiction (substance use disorder) – Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/drug-addiction/symptoms-causes/syc-20365112 |access-date=8 November 2022 |website=Mayo Clinic |language=en}}

In Ontario, Canada between 2009 and 2017, outpatient visits for mental health and addiction increased from 52.6 to 57.2 per 100 people, emergency department visits increased from 13.5 to 19.7 per 1000 people and the number of hospitalizations increased from 4.5 to 5.5 per 1000 people.{{Cite web |title=Mental Health and Addictions System Performance in Ontario: 2021 Scorecard |url=https://www.ices.on.ca/Publications/Atlases-and-Reports/2021/Mental-Health-and-Addictions-System-Performance-in-Ontario-2021-Scorecard |access-date=8 November 2022 |website=www.ices.on.ca}} Prevalence of care needed increased the most among the 14–17 age group overall.

The realities of opioid use and opioid use disorder in Latin America may be deceptive if observations are limited to epidemiological findings. In the United Nations Office on Drugs and Crime report,{{cite book |url=https://www.unodc.org/documents/data-and-analysis/WDR2012/WDR_2012_web_small.pdf |title=World Drug Report 2012 |date=June 2012 |publisher=United Nations Office on Drugs and Crime |isbn=978-92-1-148267-6}} although South America produced 3% of the world's morphine and heroin and 0.01% of its opium, prevalence of use is uneven. According to the Inter-American Commission on Drug Abuse Control, consumption of heroin is low in most Latin American countries, although Colombia is the area's largest opium producer. Mexico, because of its border with the United States, has the highest incidence of use.{{cite journal | vauthors = Pacurucu-Castillo SF, Ordóñez-Mancheno JM, Hernández-Cruz A, Alarcón RD | title = World opioid and substance use epidemic: a Latin American perspective. | journal = Psychiatric Research and Clinical Practice | date = April 2019 | volume = 1 | issue = 1 | pages = 32–8 | doi = 10.1176/appi.prcp.20180009 | pmid = 36101564 | pmc = 9175731 | doi-access = free }}

The word addiction derives from the Latin "addico", meaning "giving over" with both positive connotations (devotion, dedication) and negative ones (being enslaved to a creditor in Roman law). This dual meaning persisted in traditional English dictionaries, encompassing both legal surrender and personal devotion to habits. Later, 19th century temperance movements narrowed the definition of addiction to just drug-related disease, ignoring behavioral addictions and the possibility of positive or neutral addictions. This restrictive view opposes the current understanding of addiction.Alexander, B. K., & Schweighofer, A. R. (1988). Defining" addiction.". Canadian psychology/psychologie canadienne, 29(2), 151.

Addiction and addictive behavior are polysemes denoting a category of mental disorders, of neuropsychological symptoms, or of merely maladaptive/harmful habits and lifestyles.{{cite book |title=Addiction reimagined: challenging views of an enduring social problem |vauthors=Steverson |date=2020 |publisher=Vernon Press |isbn=978-1-62273-953-0 |pages=206}} A common use of the term addiction in medicine is for neuropsychological symptoms denoting pervasive/excessive and intense urges to engage in a category of behavioral compulsions or impulses towards sensory rewards (e.g., alcohol, betel quid, drugs, sex, gambling, video gaming).{{cite journal |vauthors=Gowing L, Ali R, Allsop S, Marsden J, Turf E, West E, Witton J |date=2015 |title=Global statistics on addictive behaviours: 2014 status report |url=https://discovery.ucl.ac.uk/id/eprint/1468912/5/West_global%2520addiction%2520report%2520final%2520mark%25202%2520clean_template.pdf |journal=Addiction |volume=110 |issue=6 |pages=904–919 |doi=10.1111/add.12899 |pmid=25963869}}{{cite journal |vauthors=Gilley |date=2018 |title=The new science of attention deficit hyperactivity disorder: news from the cutting edge of research science |url=https://www.fortunejournals.com/articles/pthe-new-science-of-attention-deficit-hyperactivity-disorder-news-from-the-cutting-edge-of-research-sciencep.html |journal=Journal of Psychiatry and Psychiatric Disorders |volume=2 |issue=3 |doi=10.26502/jppd.2572-519X0043 |doi-broken-date=1 November 2024 |s2cid=150196703 |doi-access=free}}{{cite journal |vauthors=Lee C, Ko A, Yang F |date=2018 |title=Association of DSM-5 betel-quid use disorder with oral potentially malignant disorder in 6 betel-quid endemic Asian populations |journal=JAMA Psychiatry |volume=75 |issue=3 |pages=261–269 |doi=10.1001/jamapsychiatry.2017.4307 |pmc=5885949 |pmid=29417149}}{{cite journal |vauthors=Sahithya B, Kashyap R |date=2020 |title=Sexual Addiction Disorder—a review with recent updates |journal=Journal of Psychosexual Health |volume=4 |issue=2 |pages=95–101 |doi=10.1177/26318318221081080 |s2cid=248835855 |doi-access=free}} Addictive disorders or addiction disorders are mental disorders involving high intensities of addictions (as neuropsychological symptoms) that induce functional disabilities (i.e., limit subjects' social/family and occupational activities); the two categories of such disorders are substance-use addictions and behavioral addictions.{{cite journal |vauthors=Destoop M, Morrens M, Coppens V, Dom G |date=2019 |title=Addiction, anhedonia, and comorbid mood disorder. A narrative review |journal=Frontiers in Psychiatry |volume=10 |page=311 |doi=10.3389/fpsyt.2019.00311 |pmc=6538808 |pmid=31178763 |doi-access=free}}

The etymology of the term addiction throughout history has been misunderstood and has taken on various meanings associated with the word.{{cite journal | vauthors = Crocq MA | title = Historical and cultural aspects of man's relationship with addictive drugs | journal = Dialogues in Clinical Neuroscience | volume = 9 | issue = 4 | pages = 355–361 | date = December 2007 | pmid = 18286796 | pmc = 3202501 | doi = 10.31887/DCNS.2007.9.4/macrocq | publisher = Laboratoires Servier | s2cid = 12682928 | doi-access = free | oclc = 62869913 | veditors = Thibaut F }} An example is the usage of the word in the religious landscape of early modern Europe.{{cite book | vauthors = Lemon R |year=2018 |chapter=Introduction: Addiction in (Early) Modernity |chapter-url=https://books.google.com/books?id=mwVKDwAAQBAJ&pg=PA1 |title=Addiction and Devotion in Early Modern England |location=Philadelphia |publisher=University of Pennsylvania Press |series=Haney Foundation Series |pages=1–23 |isbn=978-0-8122-4996-5}} "Addiction" at the time meant "to attach" to something, giving it both positive and negative connotations. The object of this attachment could be characterized as "good or bad".{{cite journal | vauthors = Rosenthal R, Faris S |date=February 2019 |title=The etymology and early history of 'addiction' |journal=Addiction Research & Theory |publisher=Taylor & Francis |volume=27 |issue=5 |pages=437–449 |doi=10.1080/16066359.2018.1543412 |doi-access=free |issn=1476-7392 |s2cid=150418396}} The meaning of addiction during the early modern period was mostly associated with positivity and goodness; during this early modern and highly religious era of Christian revivalism and Pietistic tendencies, it was seen as a way of "devoting oneself to another".

In contemporary modern English "-holic" is a suffix that can be added to a subject to denote an addiction to it. It was extracted from the word alcoholism (one of the first addictions to be widely identified both medically and socially) (correctly the root "alcohol" plus the suffix "-ism") by misdividing or rebracketing it into "alco" and "-holism". There are correct medico-legal terms for such addictions: dipsomania is the medico-legal term for alcoholism;{{cite web |title=Alcohol |url=http://www.etymonline.com/index.php?search=alcohol&searchmode=none |work=Online Etymology Dictionary}} other examples are in this table:{{Citation needed|date=March 2025}}

Modern research on addiction has led to a better understanding of the disease with research on the topic dating back to 1875, specifically on morphine addiction.{{cite book |last1=Institute of Medicine |title=Pathways of Addiction: Opportunities in Drug Abuse Research |date=1996 |publisher=National Academies Press |location=Washington}} This furthered the understanding of addiction being a medical condition. It was not until the 19th century that addiction was seen and acknowledged in the Western world as a disease, being both a physical condition and mental illness.{{cite journal | vauthors = Bettinardi-Angres K, Angres DH |date=July 2010 |title=Understanding the Disease of Addiction | veditors = Alexander M |journal=Journal of Nursing Regulation |publisher=Elsevier on behalf of the National Council of State Boards of Nursing |volume=1 |issue=2 |pages=31–37 |doi=10.1016/S2155-8256(15)30348-3 |issn=2155-8256 |s2cid=143289528}} Today, addiction is understood both as a biopsychosocial and neurological disorder that negatively impacts those who are affected by it, most commonly associated with the use of drugs and excessive use of alcohol. The understanding of addiction has changed throughout history, which has impacted and continues to impact the ways it is medically treated and diagnosed.{{Citation needed|date=March 2025}}

The arts can be used in a variety of ways to address issues related to addiction. Art can be used as a form of therapy in the treatment of substance use disorders. Creative activities like painting, sculpting, music, and writing can help people express their feelings and experiences in safe and healthy ways. The arts can be used as an assessment tool to identify underlying issues that may be contributing to a person's substance use disorder. Through art, individuals can gain insights into their own motivations and behaviors that can be helpful in determining a course of treatment. Finally, the arts can be used to advocate for those suffering from a substance use disorder by raising awareness of the issue and promoting understanding and compassion. Through art, individuals can share their stories, increase awareness, and offer support and hope to those struggling with substance use disorders.

Addiction treatment is complex and not always effective due to engagement and service availability concerns, so researchers prioritize efforts to improve treatment retention and decrease relapse rates.{{cite journal | vauthors = Appel PW, Ellison AA, Jansky HK, Oldak R | title = Barriers to enrollment in drug abuse treatment and suggestions for reducing them: opinions of drug injecting street outreach clients and other system stakeholders | journal = The American Journal of Drug and Alcohol Abuse | volume = 30 | issue = 1 | pages = 129–153 | date = 2004 | pmid = 15083558 | doi = 10.1081/ada-120029870 | s2cid = 20193011 }}{{cite journal | vauthors = Megranahan K, Lynskey MT | journal=The Arts in Psychotherapy | title=Do creative arts therapies reduce substance misuse? A systematic review | volume=57 | pages=50–58 | date= February 2018 | issn=0197-4556 | doi=10.1016/j.aip.2017.10.005}} Characteristics of substance abuse may include feelings of isolation, a lack of confidence, communication difficulties, and a perceived lack of control.{{cite journal | vauthors= Moore RW, W | journal=The Arts in Psychotherapy | title=Art therapy with substance abusers: A review of the literature | volume=10 | issue=4 | pages=251–260 | date=1 December 1983 | issn=0197-4556 | doi=10.1016/0197-4556(83)90026-6}} In a similar vein, people suffering from substance use disorders tend to be highly sensitive, creative, and as such, are likely able to express themselves meaningfully in creative arts such as dancing, painting, writing, music, and acting.{{Citation | vauthors=((North American Drama Therapy Association)) | year=2016 | title=Drama therapy with addictions populations}} Further evidenced by Waller and Mahony (2002){{cite book | veditors= Waller D, Mahony J | date=9 December 1998 | title=Treatment of Addiction: Current Issues for Arts Therapists | publisher=Routledge | doi=10.4324/9780203132395 | isbn=978-0-203-13239-5}} and Kaufman (1981),{{cite journal | vauthors = Kaufman GH | title = Art therapy with the addicted | journal = Journal of Psychoactive Drugs | volume = 13 | issue = 4 | pages = 353–360 | date = 1 July 1981 | pmid = 7040619 | doi = 10.1080/02791072.1981.10471892 | publisher = Taylor & Francis }} the creative arts therapies can be a suitable treatment option for this population especially when verbal communication is ineffective.

Primary advantages of art therapy in the treatment of addiction have been identified as:{{cite book |title=Treatment of Addiction: Current Issues for Arts Therapists |date=9 December 1998 |publisher=Routledge |isbn=978-0-203-13239-5 |veditors= Waller D, Mahony J |doi=10.4324/9780203132395}}{{cite book |chapter-url=https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118306543.ch35 |chapter=Art Therapy and Substance Abuse |vauthors= Schmanke L |title=The Wiley Handbook of Art Therapy |date=2015 |publisher=John Wiley & Sons, Ltd |isbn=978-1-118-30654-3 |pages=361–374 |doi=10.1002/9781118306543.ch35}}

• Assess and characterize a client's substance use issues
• Bypassing a client's resistances, defenses, and denial
• Containing shame or anger
• Facilitating the expression of suppressed and/or complicated emotions
• Highlighting a client's strengths
• Providing an alternative to verbal communication (via use of symbols) and conventional forms of therapy
• Providing clients with a sense of control
• Tackling feelings of isolation

Art therapy is an effective method of dealing with substance abuse in comprehensive treatment models. When included in psychoeducational programs, art therapy in a group setting can help clients internalize taught concepts in a more personalized manner.{{cite book | vauthors= Schmanke L | title= Art and Expressive Therapies within the Medical Model | date= 2019 | chapter=Art Therapy Applications and Substance Abuse | publisher=Routledge | edition=1st | pages=177–187 | doi=10.4324/9780429400087-16 | isbn=978-0-367-02340-9| s2cid= 208386296 }} During the course of treatment, by examining and comparing artwork created at different times, art therapists can be helpful in identifying and diagnosing issues, as well as charting the extent or direction of improvement as a person detoxifies. Where increasing adherence to treatment regimes and maintaining abstinence is the target; art therapists can aid by customizing treatment directives (encourage the client to create collages that compare pros and cons, pictures that compare past and present and future, and drawings that depict what happened when a client went off medication).

Art therapy can function as a complementary therapy used in conjunction with more conventional therapies and can can integrate with harm reduction protocols to minimize the negative effects of drug use.{{cite journal | vauthors = Chiang M, Reid-Varley WB, Fan X | title = Creative art therapy for mental illness | journal = Psychiatry Research | volume = 275 | pages = 129–136 | date = May 2019 | pmid = 30901671 | doi = 10.1016/j.psychres.2019.03.025 | s2cid = 78090920 }} An evaluation of art therapy incorporation within a pre-existing Addiction Treatment Programme based on the 12 step Minnesota Model endorsed by the Alcoholics Anonymous found that 66% of participants expressed the usefulness of art therapy as a part of treatment.{{cite journal |vauthors= Dickson C |date=June 2007 |title=An evaluation study of art therapy provision in a residential Addiction Treatment Programme (ATP) |journal=International Journal of Art Therapy |volume=12 |issue=1 |pages=17–27 |doi=10.1080/17454830701265220 |s2cid=72987664 |issn=1745-4832}} Within the weekly art therapy session, clients were able to reflect and process the intense emotions and cognitions evoked by the programme. In turn, the art therapy component of the programme fostered stronger self-awareness, exploration, and externalization of repressed and unconscious emotions of clients, promoting the development of a more integrated 'authentic self'.{{cite journal |vauthors= Matto H, Corcoran J, Fassler, A |date=January 2003 |title=Integrating solution-focused and art therapies for substance abuse treatment: guidelines for practice |journal=The Arts in Psychotherapy |volume=30 |issue=5 |pages=265–272 |doi=10.1016/j.aip.2003.08.003 |issn=0197-4556}}

Despite the large number of randomized control trials, clinical control trials, and anecdotal evidence supporting the effectiveness of art therapies for use in addiction treatment, a systematic review conducted in 2018 could not find enough evidence on visual art, drama, dance and movement therapy, or 'arts in health' methodologies to confirm their effectiveness as interventions for reducing substance misuse.{{cite journal |vauthors= Megranahan K, Lynskey MT |date=February 2018 |title=Do creative arts therapies reduce substance misuse? A systematic review |journal=The Arts in Psychotherapy |volume=57 |pages=50–58 |doi=10.1016/j.aip.2017.10.005 |issn=0197-4556}} Music therapy was identified to have potentially strong beneficial effects in aiding contemplation and preparing those diagnosed with substance use for treatment.

The Formal Elements Art Therapy Scale (FEATS) is an assessment tool used to evaluate drawings created by people suffering from substance use disorders by comparing them to drawings of a control group (consisting of individuals without SUDs).{{cite journal |vauthors= Rockwell P, Dunham M |date=January 2006 |title=The Utility of the Formal Elements Art Therapy Scale in Assessment for Substance Use Disorder |journal=Art Therapy |volume=23 |issue=3 |pages=104–111 |doi=10.1080/07421656.2006.10129625 |s2cid=5541133 |issn=0742-1656}} FEATS consists of twelve elements, three of which were found to be particularly effective at distinguishing the drawings of those with SUDs from those without: Person, Realism, and Developmental. The Person element assesses the degree to which a human features are depicted realistically, the Realism element assesses the overall complexity of the artwork, and the Developmental element assesses "developmental age" of the artwork in relation to standardized drawings from children and adolescents. By using the FEATS assessment tool, clinicians can gain valuable insight into the drawings of individuals with SUDs, and can compare them to those of the control group. Formal assessments such as FEATS provide healthcare providers with a means to quantify, standardize, and communicate abstract and visceral characteristics of SUDs to provide more accurate diagnoses and informed treatment decisions.

Other artistic assessment methods include the Bird's Nest Drawing: a useful tool for visualizing a client's attachment security.{{cite journal |vauthors= Francis D, Kaiser D, Deaver SP |date=22 April 2011 |title=Representations of Attachment Security in the Bird's Nest Drawings of Clients with Substance Abuse Disorders |url=https://www.tandfonline.com/doi/abs/10.1080/07421656.2003.10129571 |journal=Art Therapy |volume=20 |issue=3 |pages=125–137 |publisher=Routledge |doi=10.1080/07421656.2003.10129571 |s2cid=142341708 |issn=0742-1656 |access-date=4 December 2022}} This assessment method looks at the amount of color used in the drawing, with a lack of color indicating an 'insecure attachment', a factor that the client's therapist or recovery framework must take into account.{{cite journal | vauthors = Ball SA, Legow NE | title = Attachment theory as a working model for the therapist transitioning from early to later recovery substance abuse treatment | journal = The American Journal of Drug and Alcohol Abuse | volume = 22 | issue = 4 | pages = 533–547 | date = November 1996 | pmid = 8911591 | doi = 10.3109/00952999609001679 | publisher = Taylor & Francis }}

Art therapists working with children of parents suffering from alcoholism can use the Kinetic Family Drawings assessment tool to shed light on family dynamics and help children express and understand their family experiences.{{cite journal |vauthors= Holt ES, Kaiser DH |date=January 2001 |title=Indicators of Familial Alcoholism in Children's Kinetic Family Drawings |journal=Art Therapy |volume=18 |issue=2 |pages=89–95 |doi=10.1080/07421656.2001.10129751 |s2cid=141669979 |issn=0742-1656 }} The KFD can be used in family sessions to allow children to share their experiences and needs with parents who may be in recovery from alcohol use disorder. Depiction of isolation of self and isolation of other family members may be an indicator of parental alcoholism.

Stigma can lead to feelings of shame that can prevent people with substance use disorders from seeking help and interfere with provision of harm reduction services.{{cite journal | vauthors = Ashford RD, Brown AM, Curtis B | title = Systemic barriers in substance use disorder treatment: A prospective qualitative study of professionals in the field | journal = Drug and Alcohol Dependence | volume = 189 | pages = 62–69 | date = August 2018 | pmid = 29883870 | doi = 10.1016/j.drugalcdep.2018.04.033 | s2cid = 47011510 }}{{cite journal | vauthors = Barry CL, McGinty EE, Pescosolido BA, Goldman HH | title = Stigma, discrimination, treatment effectiveness, and policy: public views about drug addiction and mental illness | journal = Psychiatric Services | volume = 65 | issue = 10 | pages = 1269–1272 | date = October 2014 | pmid = 25270497 | doi = 10.1176/appi.ps.201400140 | pmc = 4285770 }}{{Citation |title=Philly Council bill to block supervised injection sites advances - WHYY |url=https://whyy.org/articles/bill-to-prevent-supervised-injection-sites-from-opening-in-philly-advances/ |year=2020 |access-date=14 December 2022 |vauthors= Feldman N}} It can influence healthcare policy, making it difficult for these individuals to access treatment.{{Citation |title=Implementation of the Provision of the Comprehensive Addiction and Recovery Act of 2016 Relating to the Dispensing of Narcotic Drugs for Opioid Use Disorder |url=https://www.federalregister.gov/documents/2018/01/23/2018-01173/implementation-of-the-provision-of-the-comprehensive-addiction-and-recovery-act-of-2016-relating-to |year=2018 |access-date=14 December 2022 |vauthors=((Drug Enforcement Administration))}}

Artists attempt to change the societal perception of addiction from a punishable moral offense to instead a chronic illness necessitating treatment. This form of advocacy can help to relocate the fight of addiction from a judicial perspective to the public health system.{{Cite book |title=Addiction and art |date=2010 |publisher=Johns Hopkins University Press | vauthors = Henningfield JE, Dowell ML, Santora PB |isbn=978-1-4214-0023-5 |location=Baltimore |oclc=794700340}}

Artists who have personally lived with addiction or undergone recovery may use art to depict their experiences in a manner that uncovers the "human face of addiction". By bringing experiences of addiction and recovery to a personal level and breaking down the "us and them", the viewer may be more inclined to show compassion, forego stereotypes and stigma of addiction, and label addiction as a social rather than individual problem.

According to Santora the main purposes in using art as a form of advocacy in the education and prevention of substance use disorders include:

• Addiction art exhibitions can come from a variety of sources, but the underlying message of these works is the same: to communicate through emotions without relying on intellectually demanding/gatekept facts and figures. These exhibitions can either stand alone, reinforce, or challenge facts.
• A powerful educational tool for increasing awareness and understanding of addiction as a medical illness. Exhibitions featuring personal stories and images can help to create lasting impressions on diverse audiences (including addiction scientists/researchers, family/friends of those affected by addiction etc.), highlighting the humanity of the problem and in turn encouraging compassion and understanding.
• A way to destigmatize substance use disorders and shift public perception from viewing them as a moral failing to understanding them as a chronic medical condition which requires treatment.
• Provide those who are struggling with addiction assurance and encouragement of healing, and let them know that they are not alone in their struggle.
• The use of visual arts can help bring attention to the lack of adequate substance use treatment, prevention, and education programs and services in a healthcare system. Messages can encourage policymakers to allocate more resources to addiction treatment and prevention from federal, state, and local levels.

The Temple University College of Public Health department conducted a project to promote awareness around opioid use and reduce associated stigma by asking students to create art pieces that were displayed on a website they created and promoted via social media. Quantitative and qualitative data was recorded to measure engagement, and the student artists were interviewed, which revealed a change in perspective and understanding, as well as greater appreciation of diverse experiences. Ultimately, the project found that art was an effective medium for empowering both the artist creating the work and the person interacting with it.{{cite journal | vauthors= Dingman DA, Zibalese-Crawford, M | journal=Journal of Alcohol & Drug Education | title=Reducing Substance Use Related Stigma through Expressions of Artwork | volume=65 | issue=1 | pages=29–39 | publisher=American Alcohol & Drug Information Foundation | date= April 2021 | issn=0090-1482}}

Another author critically examined works by contemporary Canadian artists that deal with addiction via the metaphor of a cultural landscape to "unmap" and "remap" ideologies related to Indigenous communities and addiction to demonstrate how colonial violence in Canada has drastically impacted the relationship between Indigenous peoples, their land, and substance abuse.{{cite journal | vauthors= Skelly J | journal=Journal of Canadian Studies | title=Alternative Paths: Mapping Addiction in Contemporary Art by Landon Mackenzie, Rebecca Belmore, Manasie Akpaliapik, and Ron Noganosh | volume=49 | issue=2 | pages=268–295, 356 | publisher=University of Toronto Press | date= 2015 | issn=0021-9495 | doi=10.3138/jcs.49.2.268| s2cid=148421461 }}

A project known as "Voice" was a collection of art, poetry and narratives created by women living with a history of addiction to explore women's understanding of harm reduction, challenge the effects of stigma and give voice to those who have historically been silenced or devalued. In the project, nurses with knowledge of mainstream systems, aesthetic knowing, feminism and substance use organized weekly gatherings, wherein women with histories of substance use and addiction worked alongside a nurse to create artistic expressions. Creations were presented at several venues, including an International Conference on Drug Related Harm, a Nursing Conference and a local gallery to positive community response.{{cite journal | vauthors = Paivinen H, Bade S | title = Voice: challenging the stigma of addiction; a nursing perspective | journal = The International Journal on Drug Policy | volume = 19 | issue = 3 | pages = 214–219 | date = June 2008 | pmid = 18439812 | doi = 10.1016/j.drugpo.2008.02.011 }}

File:An alcoholic man with delirium Wellcome L0060780 (level correction).jpg, otherwise known as delirium tremens]]

While regarded biomedically as a neuropsychological disorder, addiction is multi-layered, with biological, psychological, social, cultural, and spiritual (biopsychosocial–cultural–spiritual) elements.{{Cite journal | vauthors = Rau BL |date=September 2014 |title=The Oxford Handbook of Evidence-Based Management, Rousseau DM 2012. 432 pages, hardcover. New York, NY: Oxford University Press. |journal=Academy of Management Learning & Education |volume=13 |issue=3 |pages=485–487 |doi=10.5465/amle.2013.0309 |issn=1537-260X}}{{cite journal | vauthors = Daley DC | title = Family and social aspects of substance use disorders and treatment | journal = Journal of Food and Drug Analysis | volume = 21 | issue = 4 | pages = S73–S76 | date = December 2013 | pmid = 25214748 | pmc = 4158844 | doi = 10.1016/j.jfda.2013.09.038 }} A biopsychosocial–cultural–spiritual approach fosters the crossing of disciplinary boundaries, and promotes holistic considerations of addiction.{{cite journal | vauthors = Saad M, de Medeiros R, Mosini AC | title = Are We Ready for a True Biopsychosocial-Spiritual Model? The Many Meanings of "Spiritual" | journal = Medicines | volume = 4 | issue = 4 | pages = 79 | date = October 2017 | pmid = 29088101 | pmc = 5750603 | doi = 10.3390/medicines4040079 | doi-access = free }}{{Cite book | veditors = Farmer P, Kleinman A, Kim J, Basilico M |title=Reimagining Global Health: An Introduction |date=31 December 2019 |publisher=University of California Press |doi=10.1525/9780520954632 |s2cid=168489288 |isbn=978-0-520-95463-2 }}{{Cite journal | vauthors = Weakland JH |date=October 1961 |title=The Essence of Anthropological Education |journal=American Anthropologist |volume=63 |issue=5 |pages=1094–1097 |doi=10.1525/aa.1961.63.5.02a00130 |issn=0002-7294}} A biopsychosocial–cultural–spiritual approach considers, for example, how physical environments influence experiences, habits, and patterns of addiction.

Ethnographic engagements and developments in fields of knowledge have contributed to biopsychosocial–cultural–spiritual understandings of addiction, including the work of Philippe Bourgois, whose fieldwork with street-level drug dealers in East Harlem highlights correlations between drug use and structural oppression in the United States.{{Cite book | vauthors = Bourgois P |url=https://www.cambridge.org/core/product/identifier/9780511808562/type/book |title=In Search of Respect: Selling Crack in El Barrio |series=Structural Analysis in the Social Sciences |date=23 December 2002 |publisher=Cambridge University Press |isbn=978-0-521-01711-4 |edition=2 |doi=10.1017/cbo9780511808562}} Prior models that have informed the prevailing biopsychosocial–cultural–spiritual consideration of addiction include:

The cultural model, an anthropological understanding of the emergence of drug use and abuse, was developed by Dwight Heath.{{cite journal | vauthors = Singer M | title = Anthropology and addiction: an historical review | journal = Addiction | volume = 107 | issue = 10 | pages = 1747–1755 | date = October 2012 | pmid = 22962955 | doi = 10.1111/j.1360-0443.2012.03879.x }} Heath undertook ethnographic research and fieldwork with the Camba people of Bolivia from June 1956 to August 1957.{{cite journal | vauthors = Heath DB | title = Drinking patterns of the Bolivian Camba | journal = Quarterly Journal of Studies on Alcohol | volume = 19 | issue = 3 | pages = 491–508 | date = September 1958 | pmid = 13579177 | doi = 10.15288/qjsa.1958.19.491 }} Heath observed that adult members of society drank 'large quantities of rum and became intoxicated for several contiguous days at least twice a month'. This frequent, heavy drinking from which intoxication followed was typically undertaken socially, during festivals. Having returned in 1989, Heath observed that while much had changed, 'drinking parties' remained, as per his initial observations, and 'there appear to be no harmful consequences to anyone'.{{Cite journal | vauthors = Heath DB |date=January 1995 |title=Changes in Drinking Patterns in Bolivian Cultures: A Cautionary Tale About Historical Approaches |journal=Addiction Research |language=en |volume=2 |issue=3 |pages=307–318 |doi=10.3109/16066359509005215 |issn=1058-6989}} Heath's observations and interactions reflected that this form of social behavior, the habitual heavy consumption of alcohol, was encouraged and valued, enforcing social bonds in the Camba community. Despite frequent intoxication, "even to the point of unconsciousness", the Camba held no concept of alcoholism (a form of addiction), and no visible social problems associated with drunkenness, or addiction, were apparent.

As noted by Merrill Singer, Heath's findings, when considered alongside subsequent cross-cultural experiences, challenged the perception that intoxication is socially 'inherently disruptive'. Following this fieldwork, Heath proposed the 'cultural model', suggesting that 'problems' associated with heavy drinking, such as alcoholism – a recognised form addiction – were cultural: that is, that alcoholism is determined by cultural beliefs, and therefore varies among cultures. Heath's findings challenged the notion that 'continued use [of alcohol] is inexorably addictive and damaging to the consumer's health'.

The cultural model did face criticism by Sociologist Robin Room and others, who felt anthropologists could "downgrade the severity of the problem". Merrill Singer found it notable that the ethnographers working within the prominence of the cultural model were part of the 'wet generation': while not blind to the 'disruptive, dysfunctional and debilitating effects of alcohol consumption', they were products 'socialized to view alcohol consumption as normal'.

Historically, addiction has been viewed from the etic perspective, defining users through the pathology of their condition.{{Cite encyclopedia | vauthors = Burraway J |date=October 2020 | veditors = Stein F, Diemberger H, Stasch R, Robbins J, Sanchez A, Lazar S, Candea M |title=Addiction |url=https://www.anthroencyclopedia.com/entry/addiction |encyclopedia=Open Encyclopedia of Anthropology|doi=10.29164/20addiction|s2cid=241689890 |doi-access=free }} As reports of drug use rapidly increased, the cultural model found application in anthropological research exploring western drug subculture practices.

The approach evolved from the ethnographic exploration into the lived experiences and subjectivities of 1960s and 1970s drug subcultures. The seminal publication "Taking care of business", by Edward Preble and John J. Casey, documented the daily lives of New York street-based intravenous heroin users in rich detail, providing unique insight into the dynamic social worlds and activities that surrounded their drug use.{{Cite journal | vauthors = Preble E, Casey JJ |date=January 1969 |title=Taking Care of Business—The Heroin User's Life on the Street |url=http://dx.doi.org/10.3109/10826086909061998 |journal=International Journal of the Addictions |volume=4 |issue=1 |pages=1–24 |doi=10.3109/10826086909061998 |issn=0020-773X}} These findings challenge popular narratives of immorality and deviance, conceptualizing substance abuse as a social phenomenon. The prevailing culture can have a greater influence on drug taking behaviors than the physical and psychological effects of the drug itself.{{cite journal | vauthors = Golub A, Johnson BD, Dunlap E | title = Subcultural evolution and illicit drug use | journal = Addiction Research & Theory | volume = 13 | issue = 3 | pages = 217–229 | date = May 2005 | pmid = 23805068 | pmc = 3690817 | doi = 10.1080/16066350500053497 }}{{Better source needed|reason=The source doesn't really say the prevailing culture has a "greater influence" in addition to being old per MEDRS.|date=March 2023}} To marginalized individuals, drug subcultures can provide social connection, symbolic meaning, and socially constructed purpose that they may feel is unattainable through conventional means. The subcultural model demonstrates the complexities of addiction, highlighting the need for an integrated approach. It contends that a biosocial approach is required to achieve a holistic understanding of addiction.

Emerging in the early 1980s, the critical medical anthropology model was introduced, and as Merrill Singer offers 'was applied quickly to the analysis of drug use'. Where the cultural model of the 1950s looked at the social body, the critical medical anthropology model revealed the body politic, considering drug use and addiction within the context of macro level structures including larger political systems, economic inequalities, and the institutional power held over social processes.

Highly relevant to addiction, the three issues emphasized in the model are:

• Self-medication
• The social production of suffering
• The political economy (Licit and Illicit Drugs)

These three key points highlight how drugs may come to be used to self-medicate the psychological trauma of socio-political disparity and injustice, intertwining with licit and illicit drug market politics. Social suffering, "the misery among those on the weaker end of power relations in terms of physical health, mental health and lived experience", is used by anthropologists to analyze how individuals may have personal problems caused by political and economic power. From the perspective of critical medical anthropology heavy drug use and addiction is a consequence of such larger scale unequal distributions of power.

The three models developed here – the cultural model, the subcultural model, and the Critical Medical Anthropology Model – display how addiction is not an experience to be considered only biomedically. Through consideration of addiction alongside the biological, psychological, social, cultural and spiritual (biopsychosocial–spiritual) elements which influence its experience, a holistic and comprehensive understanding can be built.

{{Main|Social learning theory}}

Albert Bandura's 1977 social learning theory posits that individuals acquire addictive behaviors by observing and imitating models in their social environment.Falk, Richard; Kim, Samuel S. (2019-08-15). The War System: An Interdisciplinary Approach. Routledge. {{ISBN|978-1-000-23507-4}}"Bandura, Albert: Social Learning Theory", Encyclopedia of Criminological Theory, 2455 Teller Road, Thousand Oaks California 91320 United States: SAGE Publications, Inc., 2010, retrieved 2023-11-09 The likelihood of engaging in and sustaining similar addictive behaviors is influenced by the reinforcement and punishment observed in others. The principle of reciprocal determinism suggests that the functional relationships between personal, environmental, and behavioral factors act as determinants of addictive behavior.Smith, Mark A. (2021-02-01). "Social Learning and Addiction". Behavioural Brain Research. 398: 112954. {{doi|10.1016/j.bbr.2020.112954}} {{ISSN|0166-4328}} Thus, effective treatment targets each dynamic facet of the biopsychosocial disorder.

{{Main|Transtheoretical model}}

The transtheoretical model of change suggests that overcoming an addiction is a stepwise process that occurs through several stages.Brinthaupt, Thomas M.; Lipka, Richard P. (1994-10-11). Changing the Self: Philosophies, Techniques, and Experiences. State University of New York Press. {{ISBN|978-0-7914-9754-8}}

Precontemplation: This initial stage precedes individuals considering a change in their behavior. They might be oblivious to or in denial of their addiction, failing to recognize the need for change.

Contemplation is the stage in which individuals become aware of the problems caused by their addiction and are considering change. Although they may not fully commit, they weigh the costs and benefits of making a shift.

Preparation: Individuals in this stage are getting ready to change. They might have taken preliminary steps, like gathering information or making small commitments, in preparation for behavioral change.

Action involves actively modifying behavior by making specific, observable changes to address the addictive behavior. The action stage requires significant effort and commitment.

Maintenance: After successfully implementing a change, individuals enter the maintenance stage, where they work to sustain the new behavior and prevent relapse. This stage is characterized by ongoing effort and consolidation of gains.

Termination/relapse prevention: Recognizing that relapse is a common part of the change process, this stage focuses on identifying and addressing factors that may lead to a return to old behaviors. Relapse is viewed as an opportunity for learning and strategy adjustment, with the ultimate goal of eliminating or terminating the targeted behavior.

The transtheoretical model can be helpful in guiding development of tailored behavioral interventions that can promote lasting change. Progression through these stages may not always follow a linear path, as individuals may move back and forth between stages. Resistance to change is recognized as an expected part of the process.

Addiction causes an "astoundingly high financial and human toll" on individuals and society as a whole.{{cite book |title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience |vauthors=Malenka RC, Nestler EJ, Hyman SE |publisher=McGraw-Hill Medical |year=2009 |isbn=978-0-07-148127-4 |veditors=Sydor A, Brown RY |edition=2nd |location=New York |page=4 |chapter=Chapter 1: Basic Principles of Neuropharmacology |quote=Drug abuse and addiction exact an astoundingly high financial and human toll on society through direct adverse effects, such as lung cancer and hepatic cirrhosis, and indirect adverse effects –for example, accidents and AIDS – on health and productivity.}} In the United States, the total economic cost to society is greater than that of all types of diabetes and all cancers combined. These costs arise from the direct adverse effects of drugs and associated healthcare costs (e.g., emergency medical services and outpatient and inpatient care), long-term complications (e.g., lung cancer from smoking tobacco products, liver cirrhosis and dementia from chronic alcohol consumption, and meth mouth from methamphetamine use), the loss of productivity and associated welfare costs, fatal and non-fatal accidents (e.g., traffic collisions), suicides, homicides, and incarceration, among others.{{cite book |url=https://www.incb.org/documents/Publications/AnnualReports/AR2013/English/AR_2013_E.pdf |title=International Narcotics Control Board Report: 2013 |date=2013 |publisher=United Nations – International Narcotics Control Board |isbn=978-92-1-148274-4 |chapter=Economic consequences of drug abuse |access-date=28 September 2018 |chapter-url=https://www.incb.org/documents/Publications/AnnualReports/Thematic_chapters/English/AR_2013_E_Chapter_I.pdf}} The US National Institute on Drug Abuse has found that overdose deaths in the US have almost tripled among male and females from 2002 to 2017, with 72,306 overdose deaths reported in 2017 in the US.{{Cite news |date=9 August 2018 |title=Overdose Death Rates |publisher=National Institute on Drug Abuse |url=https://www.drugabuse.gov/related-topics/trends-statistics/overdose-death-rates |access-date=17 September 2018}} 2020 marked the year with highest number of overdose deaths over a 12-month period, with 81,000 overdose deaths, exceeding the records set in 2017.{{Cite news |date=18 December 2020 |title=Overdose Deaths Accelerating During Covid-19 |publisher=Centers For Disease Control Prevention |url=https://www.cdc.gov/media/releases/2020/p1218-overdose-deaths-covid-19.html |access-date=10 February 2021}}

{{Columns-list|colwidth=30em

|

• Autonomic nervous system
• Binge drinking
• Binge eating disorder
• Cognitive liberty
• Darwinian hedonism
• Discrimination against drug addicts
• Dopaminergic pathways
• Pavlovian-instrumental transfer
• Philosophy of medicine
• Substance dependence

}}

{{Notelist}}

{{Reflist|group=note}}

; Image legend

{{Reflist|group=Color legend}}

{{Reflist}}

{{Refbegin}}

• {{Cite journal | vauthors = Pelchat ML |date=March 2009 |title=Food Addiction in Humans |journal=The Journal of Nutrition |language=en |volume=139 |issue=3 |pages=620–622 |doi=10.3945/jn.108.097816|pmid=19176747 |doi-access=free }}
• {{cite journal | vauthors = Gordon HW | title = Laterality of Brain Activation for Risk Factors of Addiction | journal = Current Drug Abuse Reviews | volume = 9 | issue = 1 | pages = 1–18 | date = April 2016 | pmid = 26674074 | pmc = 4811731 | doi = 10.2174/1874473709666151217121309 }}
• {{cite book | vauthors = Szalavitz M |title=Unbroken Brain |year=2016 |isbn=978-1-250-05582-8 |publisher=St. Martin's Press |url-access=registration |url=https://archive.org/details/unbrokenbrainrev0000szal }}
• {{cite book |last1=Courtwright |first1=David T. |title=The Age of Addiction: How Bad Habits Became Big Business |date=2019 |publisher=Harvard University Press |location=Cambridge, Massachusetts |isbn=9780674248229}}

{{Refend}}

{{wiktionary|-ism}}

{{wiktionary|-holic}}

{{Commons category}}

• {{cite web |url=http://learn.genetics.utah.edu/content/addiction/ |title=The Science of Addiction: Genetics and the Brain |author= |website=learn.genetics.utah.edu |publisher=Learn.Genetics – University of Utah }}
• [http://www.tedmed.com/talks/show?id=309096 Why do our brains get addicted?] – a TEDMED 2014 talk by Nora Volkow, the director of the National Institute on Drug Abuse at NIH.

Kyoto Encyclopedia of Genes and Genomes (KEGG) signal transduction pathways:

• [http://www.genome.jp/kegg-bin/show_pathway?hsa05034+2354 KEGG – human alcohol addiction]
• [http://www.genome.jp/kegg-bin/show_pathway?hsa05031+2354 KEGG – human amphetamine addiction]
• [http://www.genome.jp/kegg-bin/show_pathway?hsa05030+2354 KEGG – human cocaine addiction]

{{Medical resources

| ICD10 = {{ICD10|F10-F19}} subdivision .2

}}

{{Addiction|state=collapsed}}

{{Drug use|state=collapsed}}

{{Portal bar|Psychology|Medicine|Biology}}

{{Authority control}}

*

Category:Brain disorders

Category:Substance-related disorders