thought disorder

Thought content is the subject of an individual's thoughts, or the types of ideas expressed by the individual.{{Cite book |last1=Blitzstein |first1=Sean |title=First aid for the psychiatry clerkship |last2=Ganti |first2=Latha |last3=Kaufman |first3=Matthew S. |date=2022 |publisher=McGraw Hill |isbn=978-1-264-25784-3 |edition=6th |location=New York}} Mental health professionals define normal thought content as the absence of significant abnormalities, distortions, or harmful thoughts. Normal thought content aligns with reality, is appropriate to the situation, and does not cause significant distress or impair functioning.{{Cite journal |last1=Snyderman |first1=Danielle |last2=Rovner |first2=Barry |date=2009-10-15 |title=Mental status exam in primary care: a review |url=https://pubmed.ncbi.nlm.nih.gov/19835342/ |journal=American Family Physician |volume=80 |issue=8 |pages=809–814 |issn=1532-0650 |pmid=19835342}}

A person's cultural background must be considered when assessing thought content. Abnormalities in thought content differ across cultures.{{Cite journal |last=APA Work Group on Psychiatric Evaluation |date=January 2021 |title=The American Psychiatric Association Practice Guidelines for the Psychiatric Evaluation of Adults: Guideline V. Assessment of Cultural Factors |url=https://psychiatryonline.org/doi/10.1176/appi.focus.18105 |journal=Focus |language=en |volume=18 |issue=1 |pages=71–74 |doi=10.1176/appi.focus.18105 |pmid=32015730 |issn=1541-4094|pmc=6996070 }} Specific types of abnormal thought content can be features of different psychiatric illnesses.{{Cite journal |last1=Norris |first1=David R. |last2=Clark |first2=Molly S. |date=2021-04-01 |title=The Suicidal Patient: Evaluation and Management |url=https://pubmed.ncbi.nlm.nih.gov/33788523/ |journal=American Family Physician |volume=103 |issue=7 |pages=417–421 |issn=1532-0650 |pmid=33788523}}

Examples of disordered thought content include:

• Suicidal thinking: thoughts of ending one's own life.{{Cite book |title=Practical guide to history taking, physical exam, and functioning in the hospital and clinic |date=2025 |publisher=McGraw Hill |isbn=978-1-264-27803-9 |editor-last=Goldberg |editor-first=Charlie |series=Lange medical book |location=New York}}
• Homicidal thinking: thoughts of ending the life of another.
• Delusion: A fixed, false belief that a person holds despite contrary evidence and that is not a shared cultural belief.
• Paranoid ideation: thoughts, not severe enough to be considered delusions, involving excessive suspicion or the belief that one is being harassed, persecuted, or unfairly treated.{{Cite book |title=Pocket psychiatry |date=2020 |publisher=Wolters Kluwer |isbn=978-1-9751-1793-1 |editor-last=Puckett |editor-first=Judith A. |series=Pocket notebook |location=Philadelphia |editor-last2=Beach |editor-first2=Scott R. |editor-last3=Taylor |editor-first3=John B.}}

• Preoccupation: excessive and/or distressing thoughts that are stressor-related and associated with negative emotions.{{Cite journal |last1=Eberle |first1=David J. |last2=Maercker |first2=Andreas |date=March 2022 |title=Preoccupation as psychopathological process and symptom in adjustment disorder: A scoping review |journal=Clinical Psychology & Psychotherapy |language=en |volume=29 |issue=2 |pages=455–468 |doi=10.1002/cpp.2657 |issn=1063-3995 |pmc=9291616 |pmid=34355464}}
• Obsession: a repetitive thought that is intrusive or inappropriate and distressing or upsetting.
• Compulsion: A repeated behavior or mental act done in response to an obsession. It aims to reduce anxiety or distress. But, it is not feasibly related to the anxiety-provoking stimulus. It is excessive and distressing.
• Magical thinking: A false belief in a causal link between actions and events. The mistaken belief that one's thoughts, words, or actions can cause or prevent an outcome in a way that violates the laws of cause and effect.
• Overvalued ideas: false or exaggerated belief held with conviction, but without delusional intensity.
• Phobias: irrational fears of objects or circumstances that are persistent.

• Poverty of thought: abnormally few thoughts and ideas expressed.
• Overabundance of thought: abnormally many thoughts and ideas expressed.

Thought process is a person's form, flow, and coherence of thinking. This is how they use language and put ideas together. A normal thought process is logical, linear, meaningful, and goal-directed. A logical, linear thought process is one that demonstrates rational connections between thoughts in a way that is sequential that allows others to understand. Thought process is not what a person thinks, rather it is how a person expresses their thoughts.{{Cite web |title=ADMSEP - Clinical Simulation Initiative eModules |url=https://www.admsep.org/csi-emodules.php?c=psych-interview&v=y |access-date=2025-01-14 |website=www.admsep.org}}

Formal thought disorder (FTD), also known as disorganized speech or disorganized thinking, is a disorder of a person's thought process in which they are unable to express their thoughts in a logical and linear fashion.{{Cite web |title=APA Dictionary of Psychology |url=https://dictionary.apa.org/formal-thought-disorder |access-date=2025-01-14 |website=dictionary.apa.org |language=en}} To be considered FTD, disorganized thinking must be severe enough that it impairs effective communication.{{Cite book |title=Diagnostic and statistical manual of mental disorders: DSM-5-TR |date=2022 |publisher=American Psychiatric Association Publishing |isbn=978-0-89042-575-6 |editor-last=American Psychiatric Association |edition=Fifth edition, text revision |location=Washington, DC}} Disorganized speech is a core symptom of psychosis, and therefore can be a feature of any condition that has a potential to cause psychosis, including schizophrenia, mania, major depressive disorder, delirium, postpartum psychosis, major neurocognitive disorder, and substance induced psychosis. FTD reflects a cluster of cognitive, linguistic, and affective disturbances, and has generated research interest from the fields of cognitive neuroscience, neurolinguistics, and psychiatry.

It can be subdivided into clusters of positive and negative symptoms and objective (rather than subjective) symptoms. On the scale of positive and negative symptoms, they have been grouped into positive formal thought disorder (posFTD) and negative formal thought disorder (negFTD). Positive subtypes were pressure of speech, tangentiality, derailment, incoherence, and illogicality; negative subtypes were poverty of speech and poverty of content. The two groups were posited to be at either end of a spectrum of normal speech, but later studies showed them to be poorly correlated. A comprehensive measure of FTD is the Thought and Language Disorder (TALD) Scale.{{cite journal | vauthors = Kircher T, Krug A, Stratmann M, Ghazi S, Schales C, Frauenheim M, Turner L, Fährmann P, Hornig T, Katzev M, Grosvald M, Müller-Isberner R, Nagels A | display-authors = 6 | title = A rating scale for the assessment of objective and subjective formal Thought and Language Disorder (TALD) | journal = Schizophrenia Research | volume = 160 | issue = 1–3 | pages = 216–21 | date = December 2014 | pmid = 25458572 | doi = 10.1016/j.schres.2014.10.024 | doi-access = free | hdl = 10576/4730 | hdl-access = free }} The Kiddie Formal Thought Disorder Rating Scale (K-FTDS) can be used to assess the presence of formal thought disorder in children and their childhood.{{Cite book |title=Play diagnosis and assessment |date=2000 |publisher=Wiley |isbn=978-0-471-25457-7 |editor-last=Sandgrund |editor-first=Alice |edition=2nd |location=New York |editor-last2=Schaefer |editor-first2=Charles E.}} Although it is very extensive and time-consuming, its results are in great detail and reliable.{{cite journal |last1=de Bruin |first1=Esther I. |last2=Verheij |first2=Fop |last3=Wiegman |first3=Tamar |last4=Ferdinand |first4=Robert F. |title=Assessment of formal thought disorder: The relation between the Kiddie Formal Thought Disorder Rating Scale and clinical judgment |journal=Psychiatry Research |date=January 2007 |volume=149 |issue=1–3 |pages=239–246 |doi=10.1016/j.psychres.2006.01.018 |pmid=17156854 }}

Nancy Andreasen preferred to identify TDs as thought-language-communication disorders (TLC disorders).{{Cite journal |last=Andreasen |first=N. C. |date=1986-01-01 |title=Scale for the Assessment of Thought, Language, and Communication (TLC) |url=https://academic.oup.com/schizophreniabulletin/article-lookup/doi/10.1093/schbul/12.3.473 |journal=Schizophrenia Bulletin |language=en |volume=12 |issue=3 |pages=473–482 |doi=10.1093/schbul/12.3.473 |pmid=3764363 |issn=0586-7614}}{{cite journal | vauthors = Andreasen NC | title = Thought, language, and communication disorders. I. Clinical assessment, definition of terms, and evaluation of their reliability | journal = Archives of General Psychiatry | volume = 36 | issue = 12 | pages = 1315–21 | date = November 1979 | pmid = 496551 | doi = 10.1001/archpsyc.1979.01780120045006 }} Up to seven domains of FTD have been described on the Thought, Language, Communication (TLC) Scale, with most of the variance accounted for by two or three domains. Some TLC disorders are more suggestive of severe disorder, and are listed with the first 11 items.

The DSM-5 categorizes FTD as "a psychotic symptom, manifested as bizarre speech and communication." FTD may include incoherence, peculiar words, disconnected ideas, or a lack of unprompted content expected from normal speech.{{cite book |title=Diagnostic and statistical manual of mental disorders : DSM-5. |date=2013 |publisher=American Psychiatric Association |location=Arlington, VA |isbn=9780890425558 |edition=5th}} Clinical psychologists typically assess FTD by initiating an exploratory conversation with patients and observing the patient's verbal responses.{{cite web |title=Thought Disorder {{!}} Johns Hopkins Psychiatry Guide |url=https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787025/all/Thought_Disorder#:~:text=In%20clinical%20practice%2C%20formal%20thought,are%20excluded%20from%20the%20diagnosis |website=www.hopkinsguides.com |language=en}}

FTD is often used to establish a diagnosis of schizophrenia; in cross-sectional studies, 27 to 80 percent of patients with schizophrenia present with FTD. A hallmark feature of schizophrenia, it is also widespread amongst other psychiatric disorders; up to 60 percent of those with schizoaffective disorder and 53 percent of those with clinical depression demonstrate FTD, suggesting that it is not exclusive to schizophrenia. About six percent of healthy subjects exhibit a mild form of FTD.{{cite journal |last1=Kircher |first1=Tilo |last2=Bröhl |first2=Henrike |last3=Meier |first3=Felicitas |last4=Engelen |first4=Jennifer |title=Formal thought disorders: from phenomenology to neurobiology |journal=The Lancet Psychiatry |date=June 2018 |volume=5 |issue=6 |pages=515–526 |doi=10.1016/S2215-0366(18)30059-2 |pmid=29678679 |s2cid=5036067 }} The DSM-5-TR mentions that less severe FTD may happen during the initial (prodromal) and residual periods of schizophrenia.

The characteristics of FTD vary amongst disorders. A number of studies indicate that FTD in mania is marked by irrelevant intrusions and pronounced combinatory thinking, usually with a playfulness and flippancy absent from patients with schizophrenia.{{cite journal |last1=Holzman |first1=P. S. |last2=Shenton |first2=M. E. |last3=Solovay |first3=M. R. |title=Quality of Thought Disorder in Differential Diagnosis |journal=Schizophrenia Bulletin |date=January 1986 |volume=12 |issue=3 |pages=360–372 |doi=10.1093/schbul/12.3.360 |pmid=3764357 }}{{cite journal |last1=Nestor |first1=Paul G. |last2=Shenton |first2=Martha E. |last3=Wible |first3=Cindy |last4=Hokama |first4=Hiroto |last5=O'Donnell |first5=Brian F. |last6=Law |first6=Susan |last7=McCarley |first7=Robert W. |title=A neuropsychological analysis of schizophrenic thought disorder |journal=Schizophrenia Research |date=February 1998 |volume=29 |issue=3 |pages=217–225 |doi=10.1016/S0920-9964(97)00101-1 |pmid=9516662 }}{{cite journal |last1=Solovay |first1=Margie R. |title=Comparative Studies of Thought Disorders: I. Mania and Schizophrenia |journal=Archives of General Psychiatry |date=January 1987 |volume=44 |issue=1 |pages=13–20 |doi=10.1001/archpsyc.1987.01800130015003 |pmid=3800579 }} The FTD present in patients with schizophrenia was characterized by disorganization, neologism, and fluid thinking, and confusion with word-finding difficulty.

There is limited data on the longitudinal course of FTD.{{cite journal |last1=Yalincetin |first1=Berna |last2=Bora |first2=Emre |last3=Binbay |first3=Tolga |last4=Ulas |first4=Halis |last5=Akdede |first5=Berna Binnur |last6=Alptekin |first6=Koksal |title=Formal thought disorder in schizophrenia and bipolar disorder: A systematic review and meta-analysis |journal=Schizophrenia Research |date=July 2017 |volume=185 |pages=2–8 |doi=10.1016/j.schres.2016.12.015 |pmid=28017494 }} The most comprehensive longitudinal study of FTD by 2023 found a distinction in the longitudinal course of thought-disorder symptoms between schizophrenia and other psychotic disorders. The study also found an association between pre-index assessments{{clarify|date=April 2023|reason=What are pre-index assessments?}} of social, work and educational functioning and the longitudinal course of FTD.{{cite journal |last1=Marengo |first1=J. T. |last2=Harrow |first2=M. |title=Longitudinal Courses of Thought Disorder in Schizophrenia and Schizoaffective Disorder |journal=Schizophrenia Bulletin |date=January 1997 |volume=23 |issue=2 |pages=273–285 |doi=10.1093/schbul/23.2.273 |pmid=9165637 }}

Several theories have been developed to explain the causes of formal thought disorder. It has been proposed that FTD relates to neurocognition via semantic memory. Semantic network impairment in people with schizophrenia{{Em dash}}measured by the difference between fluency (e.g. the number of animals' names produced in 60 seconds) and phonological fluency (e.g. the number of words beginning with "F" produced in 60 seconds){{Em dash}}predicts the severity of formal thought disorder, suggesting that verbal information (through semantic priming) is unavailable. Other hypotheses include working memory deficit (being confused about what has already been said in a conversation) and attentional focus.{{cite book | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | vauthors = Harvey PD, Keefe RS, Eesley CE | chapter = 12.10 Neurocognition in Schizophrenia | at = RELATIONSHIP OF NEUROCOGNITIVE IMPAIRMENT TO SCHIZOPHRENIA SYMPTOMS, Formal Thought Disorder}}

FTD in schizophrenia has been found to be associated with structural and functional abnormalities in the language network, where structural studies have found bilateral grey matter deficits; deficits in the bilateral inferior frontal gyrus, bilateral inferior parietal lobule and bilateral superior temporal gyrus are FTD correlates. Other studies did not find an association between FTD and structural aberrations of the language network, however, and regions not included in the language network have been associated with FTD. Future research is needed to clarify whether there is an association with FTD in schizophrenia and neural abnormalities in the language network.

Transmitter systems which might cause FTD have also been investigated. Studies have found that glutamate dysfunction, due to a rarefaction of glutamatergic synapses in the superior temporal gyrus in patients with schizophrenia, is a major cause of positive FTD.

The heritability of FTD has been demonstrated in a number of family and twin studies. Imaging genetics studies, using a semantic verbal-fluency task performed by the participants during functional MRI scanning, revealed that alleles linked to glutamatergic transmission contribute to functional aberrations in typical language-related brain areas. FTD is not solely genetically determined, however; environmental influences, such as allusive thinking in parents during childhood, and environmental risk factors for schizophrenia (including childhood abuse, migration, social isolation, and cannabis use) also contribute to the pathophysiology of FTD.{{cite journal |last1=de Sousa |first1=Paulo |last2=Spray |first2=Amy |last3=Sellwood |first3=William |last4=Bentall |first4=Richard P. |title='No man is an island'. Testing the specific role of social isolation in formal thought disorder |journal=Psychiatry Research |date=December 2015 |volume=230 |issue=2 |pages=304–313 |doi=10.1016/j.psychres.2015.09.010 |pmid=26384574 }}

The origins of FTD have been theorised from a social-learning perspective. Singer and Wynne said that familial communication patterns play a key role in shaping the development of FTD; dysfunctional social interactions undermine a child's development of cohesive, stable mental representations of the world, increasing their risk of developing FTD.{{cite journal |last1=Singer |first1=Margaret Thaler |last2=WYNNE |first2=LC |title=Thought Disorder and Family Relations of Schizophrenics: IV. Results and Implications |journal=Archives of General Psychiatry |date=February 1965 |volume=12 |issue=2 |pages=201–212 |doi=10.1001/archpsyc.1965.01720320089010 |pmid=14237630 }}

Antipsychotic medication is often used to treat FTD. Although the vast majority of studies of the efficacy of antipsychotic treatment do not report effects on syndromes or symptoms, six older studies report the effects of antipsychotic treatment on FTD.{{cite journal |last1=Cuesta |first1=Manuel J. |last2=Peralta |first2=Victor |last3=De Leon |first3=Jose |title=Schizophrenic syndromes associated with treatment response |journal=Progress in Neuro-Psychopharmacology and Biological Psychiatry |date=January 1994 |volume=18 |issue=1 |pages=87–99 |doi=10.1016/0278-5846(94)90026-4 |pmid=7906897 }}{{cite journal |last1=Wang |first1=X |last2=Savage |first2=R |last3=Borisov |first3=A |last4=Rosenberg |first4=J |last5=Woolwine |first5=B |last6=Tucker |first6=M |last7=May |first7=R |last8=Feldman |first8=J |last9=Nemeroff |first9=C |last10=Miller |first10=A |title=Efficacy of risperidone versus olanzapine in patients with schizophrenia previously on chronic conventional antipsychotic therapy: A switch study |journal=Journal of Psychiatric Research |date=October 2006 |volume=40 |issue=7 |pages=669–676 |doi=10.1016/j.jpsychires.2006.03.008 |pmid=16762371 }}{{cite journal |last1=Remberk |first1=Barbara |last2=Namysłowska |first2=Irena |last3=Rybakowski |first3=Filip |title=Cognition and communication dysfunctions in early-onset schizophrenia: Effect of risperidone |journal=Progress in Neuro-Psychopharmacology and Biological Psychiatry |date=December 2012 |volume=39 |issue=2 |pages=348–354 |doi=10.1016/j.pnpbp.2012.07.007 |pmid=22819848 }}{{cite journal |last1=Namyslowska |first1=Irena |title=Thought disorders in schizophrenia before and after pharmacological treatment |journal=Comprehensive Psychiatry |date=January 1975 |volume=16 |issue=1 |pages=37–42 |doi=10.1016/0010-440X(75)90018-8 |pmid=1109833 }}{{cite journal |last1=Hurt |first1=Stephen W. |title=Thought Disorder: The Measurement of Its Changes |journal=Archives of General Psychiatry |date=December 1983 |volume=40 |issue=12 |pages=1281–1285 |doi=10.1001/archpsyc.1983.01790110023005 |pmid=6139992 }}{{cite journal |last1=Spohn |first1=H. E. |last2=Coyne |first2=L. |last3=Larson |first3=J. |last4=Mittleman |first4=F. |last5=Spray |first5=J. |last6=Hayes |first6=K. |title=Episodic and Residual Thought Pathology in Chronic Schizophrenics: Effect of Neuroleptics |journal=Schizophrenia Bulletin |date=January 1986 |volume=12 |issue=3 |pages=394–407 |doi=10.1093/schbul/12.3.394 |pmid=2876514 }} These studies and clinical experience indicate that antipsychotics are often an effective treatment for patients with positive or negative FTD, but not all patients respond to them.

Cognitive behavioural therapy (CBT) is another treatment for FTD, but its effectiveness has not been well-studied. Large randomised controlled trials evaluating the effectiveness of CBT for treating psychosis often exclude individuals with severe FTD because it reduces the therapeutic alliance required by the therapy.{{cite journal |last1=Palmier-Claus |first1=Jasper |last2=Griffiths |first2=Robert |last3=Murphy |first3=Elizabeth |last4=Parker |first4=Sophie |last5=Longden |first5=Eleanor |last6=Bowe |first6=Samantha |last7=Steele |first7=Ann |last8=French |first8=Paul |last9=Morrison |first9=Anthony |last10=Tai |first10=Sara |title=Cognitive behavioural therapy for thought disorder in psychosis |journal=Psychosis |date=2 October 2017 |volume=9 |issue=4 |pages=347–357 |doi=10.1080/17522439.2017.1363276 |url=https://eprints.lancs.ac.uk/id/eprint/131759/2/ARC_PSYCHOSIS_FOR_SUBMISSION_CBT_FTD.pdf }} However, provisional evidence suggests that FTD may not preclude the effectiveness of CBT.

Kircher and colleagues have suggested that the following methods should be used in CBT for patients with FTD:

• Practice structuring, summarizing, and feedback methods
• Repeat and clarify the core issues and main emotions that the patient is trying to communicate
• Gently encourage patients to clarify what they are trying to communicate
• Ask patients to clearly state their communication goal
• Ask patients to slow down and explain how one point leads to another
• Help patients identify the links between ideas
• Identify the main affect linked to the thought disorder
• Normalize problems with thinking

Language abnormalities exist in the general population, and do not necessarily indicate a condition.{{cite journal |last1=Çokal |first1=Derya |last2=Sevilla |first2=Gabriel |last3=Jones |first3=William Stephen |last4=Zimmerer |first4=Vitor |last5=Deamer |first5=Felicity |last6=Douglas |first6=Maggie |last7=Spencer |first7=Helen |last8=Turkington |first8=Douglas |last9=Ferrier |first9=Nicol |last10=Varley |first10=Rosemary |last11=Watson |first11=Stuart |last12=Hinzen |first12=Wolfram |title=The language profile of formal thought disorder |journal=npj Schizophrenia |date=19 September 2018 |volume=4 |issue=1 |page=18 |doi=10.1038/s41537-018-0061-9 |pmid=30232371 |pmc=6145886 }} They can occur in schizophrenia and other disorders (such as mania or depression), or in anyone who may be tired or stressed.{{harvp | Thought Disorder | 2016 | loc = 25.3. What Are the Boundaries of Thought Disorder?., pp. 498–499. }} To distinguish thought disorder, patterns of speech, severity of symptoms, their frequency, and any resulting functional impairment can be considered.

Symptoms of FTD include derailment, pressured speech, poverty of speech, tangentiality, and thought blocking. The most common forms of FTD observed are tangentiality and circumstantiality.{{Cite web |title=UpToDate |url=https://www.uptodate.com/contents/schizophrenia-in-adults-clinical-features-assessment-and-diagnosis |access-date=2025-01-14 |website=www.uptodate.com}} FTD is a hallmark feature of schizophrenia, but is also associated with other conditions that can cause psychosis (including mood disorders, dementia, mania, and neurological diseases). Impaired attention, poor memory, and difficulty formulating abstract concepts may also reflect TD, and can be observed and assessed with mental-status tests such as serial sevens or memory tests.{{harvp | Thought Disorder | 2016 | loc = 25.2. Definition., pp. 497–498. }} cited {{cite book | vauthors = Fish FJ | year = 1962 | title = Schizophrenia | location = Bristol, England | publisher = Bright }}

Thirty symptoms (or features) of TD have been described, including:{{harvp | Thought Disorder | 2016 | loc = 25.4. What Are the Common Types of Thought Disorder?, pp. 498–499. }}

• Alogia: A poverty of speech in amount or content, it is classified as a negative symptom of schizophrenia. When further classifying symptoms, poverty of speech content (little meaningful content with a normal amount of speech) is a disorganization symptom.{{harvp | Phenomenology of Schizophrenia | 2017 | loc = THE SYMPTOMS OF SCHIZOPHRENIA, Categories of Negative Symptoms. }}
• "... In this way, alogia is conceived of as a 'negative thought disorder.' ..."
• "... The paucity of meaningful content in the presence of a normal amount of speech that is sometimes included in alogia is actually a disorganization of thought and not a negative symptom and is properly included in the disorganization cluster of symptoms. ..." Under SANS, thought blocking is considered a part of alogia, and so is increased latency in response.{{harvp | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 | loc = "6 Psychiatric Rating Scales", Table 6–5 Scale for the Assessment of Negative Symptoms (SANS), p. 44. }}
• Circumstantial speech (also known as circumstantial thinking):Houghtalen, Rory P; McIntyre, John S (2017). "7.1 Psychiatric Interview, History, and Mental Status Examination of the Adult Patient". In Sadock, Virginia A; Sadock, Benjamin J; Ruiz, Pedro (eds.). Kaplan & Sadock's Comprehensive Textbook of Psychiatry (10th ed.). Wolters Kluwer. HISTORY AND EXAMINATION, Thought Process/Form, Table 7.1–6. Examples of Disordered Thought Process/Form. {{ISBN|978-1-4511-0047-1}}. indicates and briefly defines the follow types: Clanging, Circumstantial, Derailment (loose associations), Flight of ideas, Incoherence (word salad), Neologism, Tangential, Thought blocking An inability to answer a question without excessive, unnecessary or irrelevant detail.{{cite book | vauthors = Videbeck S | year = 2017 | title = Psychiatric-Mental Health Nursing | edition = 7th | publisher = Wolters Kluwer | isbn = 9781496355911 | chapter = 8. Assessment | at = CONTENT OF THE ASSESSMENT, Thought Process and Content, p. 232. }} The point of the conversation is eventually reached, unlike in tangential speech. A patient may answer the question "How have you been sleeping lately?" with "Oh, I go to bed early, so I can get plenty of rest. I like to listen to music or read before bed. Right now I'm reading a good mystery. Maybe I'll write a mystery someday. But it isn't helping, reading I mean. I have been getting only 2 or 3 hours of sleep at night."{{harvp | Videbeck |2017 | loc = Chapter 16 Schizophrenia, APPLICATION OF THE NURSING PROCESS, Thought Process and Content, p. 446. }}
• Clanging: An instance where ideas are related only by phonetics (similar or rhyming sounds) rather than actual meaning.{{cite book |last=Videbeck |first=S |title=Psychiatric-Mental Health Nursing, 4th ed. |year=2008 |publisher=Wolters Kluwers Health, Lippincott Williams & Wilkins |location=Philadelphia}}{{cite web |title=Thought disorder |url=https://www.thenationalcouncil.org/wp-content/uploads/2018/07/Disorganized-Symptoms-of-Psychosis-Slides.pdf |access-date=26 February 2020}} This may be heard as excessive rhyming or alliteration ("Many moldy mushrooms merge out of the mildewy mud on Mondays", or "I heard the bell. Well, hell, then I fell"). It is most commonly seen in the manic phase of bipolar disorder, although it is also often observed in patients with schizophrenia and schizoaffective disorder.
• Derailment (also known as loosening of associations and knight's move thinking): Thought frequently moves from one idea to another which is obliquely related or unrelated, often appearing in speech but also in writing{{harvp | APA dictionary of psychology | 2015 | p = 299 }} "derailment n. a symptom of thought disorder, often occurring in individuals with schizophrenia, marked by frequent interruptions in thought and jumping from one idea to another unrelated or indirectly related idea. It is usually manifested in speech (speech derailment) but can also be observed in writing. Derailment is essentially equivalent to loosening of associations. See cognitive derailment; thought derailment." ("The next day when I'd be going out you know, I took control, like uh, I put bleach on my hair in California"),{{harvp | Thought Disorder | 2016 | loc = 25.4.2.8. Distractible Speech, p. 502. }}
• Distractible speech: In mid-speech, the subject is changed in response to a nearby stimulus ("Then I left San Francisco and moved to ... Where did you get that tie?"){{cite APA Dictionary |title=Distractible speech |shortlink=distractible-speech |access-date=3 March 2020 }}
• Echolalia:{{harvp | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 | loc = "10 Schizophrenia", CLINICAL FEATURES, Thought, pp. 168–169. }}
• "Form of Thought. Disorders of the form of thought are objectively observable in patients' spoken and written language. The disorders include looseness of associations, derailment, incoherence, tangentiality, circumstantiality, neologisms, echolalia, verbigeration, word salad, and mutism."
• "Thought Process. ... Disorders of thought process include flight of ideas, thought blocking, impaired attention, poverty of thought content, poor abstraction abilities, perseveration, idiosyncratic associations (e.g., identical predicates and clang associations), overinclusion, and circumstantiality."

Echoing of another's speech, once or in repetition. It may involve repeating only the last few words (or the last word) of another person's sentences, and is common on the autism spectrum and in Tourette syndrome.{{cite journal |last1=Ganos |first1=Christos |last2=Ogrzal |first2=Timo |last3=Schnitzler |first3=Alfons |last4=Münchau |first4=Alexander |title=The pathophysiology of echopraxia/echolalia: Relevance to Gilles De La Tourette syndrome |journal=Movement Disorders |date=September 2012 |volume=27 |issue=10 |pages=1222–1229 |doi=10.1002/mds.25103 |pmid=22807284 }}{{Cite book |title=Handbook of autism and pervasive developmental disorders |volume=1: Diagnosis, development, neurobiology, and behavior|date=2005|publisher=John Wiley|author=Fred R. Volkmar |display-authors=etal |isbn=978-0-470-93934-5|edition=3rd |location=Hoboken, NJ|oclc=60394857}}{{pn|date=September 2024}}{{Cite book|last=Duffy|first=Joseph R. |title=Motor speech disorders: substrates, differential diagnosis, and management|date=2013|isbn=978-0-323-07200-7|edition=Third |location=St. Louis, MI|oclc=819941855}}{{pn|date=September 2024}}

• Evasion: The next logical idea in a sequence is replaced with another idea closely (but not accurately or appropriately) related to it; also known as paralogia and perverted logic.{{cite APA Dictionary |title=Evasion |shortlink=evasion |access-date=23 February 2020 }}{{harvp | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | 2017 | loc = Appendix B Glossary of Psychiatry and Psychology Terms. }} "evasion ... consists of suppressing an idea that is next in a thought series and replacing it with another idea closely related to it. Also called paralogia; perverted logic."
• Flight of ideas: A form of FTD marked by abrupt leaps from one topic to another, possibly with discernible links between successive ideas, perhaps governed by similarities between subjects or by rhyming, puns, wordplay, or innocuous environmental stimuli (such as the sound of birds chirping). It is most characteristic of the manic phase of bipolar disorder.
• Illogicality:{{harvp | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 | loc = "Chapter 6 Psychiatric Rating Scales", OTHER SCALES, Table 6–6 Scale for the Assessment of Positive Symptoms (SAPS), Positive formal thought disorder, p. 45 }} includes and defines Derailment, Tangentiality, Incoherence, Illogicality, Circumstantiality, Pressure of speech, Distractible speech, Clanging. Conclusions are reached which do not follow logically (non sequiturs or faulty inferences). "Do you think this will fit in the box?" is answered with, "Well of course; it's brown, isn't it?"
• Incoherence (word salad): Speech which is unintelligible because the individual words are real, but the manner in which they are strung together results in gibberish. The question "Why do people comb their hair?" elicits a response like "Because it makes a twirl in life, my box is broken help me blue elephant. Isn't lettuce brave? I like electrons, hello please!"
• Neologisms: Completely new words (or phrases) whose origins and meanings are usually unrecognizable ("I got so angry I picked up a dish and threw it at the geshinker").{{harvp | Thought Disorder | 2016 | loc = 25.4.2.6. Neologisms, p. 502. }} They may also involve elisions of two words which are similar in meaning or sound.{{cite journal|author2-link=Martin Rossor | vauthors = Rohrer JD, Rossor MN, Warren JD | title = Neologistic jargon aphasia and agraphia in primary progressive aphasia | journal = Journal of the Neurological Sciences | volume = 277 | issue = 1–2 | pages = 155–9 | date = February 2009 | pmid = 19033077 | pmc = 2633035 | doi = 10.1016/j.jns.2008.10.014 }} Although neologisms may refer to words formed incorrectly whose origins are understandable (such as "headshoe" for "hat"), these can be more clearly referred to as word approximations.{{harvp | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 | loc = "Chapter 4 Signs and Symptoms in Psychiatry", GLOSSARY OF SIGNS AND SYMPTOMS, p. 29 }}
• Overinclusion: The failure to eliminate ineffective, inappropriate, irrelevant, extraneous details associated with a particular stimulus.{{cite book | ref = {{harvid | The Mental Status Examination | 2016 }} | veditors = Fatemi SH, Clayton PJ | year = 2016 | title = The Medical Basis of Psychiatry | edition = 4th | location = New York | publisher = Springer Science+Business Media | isbn = 978-1-4939-2528-5 | doi = 10.1007/978-1-4939-2528-5 | vauthors = Akiskal HS | chapter = 1 The Mental Status Examination | at = 1.5.5. Speech and Thought., pp. 8–10 }}
• "This form of thought is most characteristic of mania and tends to be overinclusive, with difficulty in excluding irrelevant, extraneous details from the association."{{harvp | APA dictionary of psychology |2015 | p = 751 }} overinclusion n. failure of an individual to eliminate ineffective or inappropriate responses associated with a particular stimulus.
• Perseveration: Persistent repetition of words or ideas, even when another person tries to change the subject. ("It's great to be here in Nevada, Nevada, Nevada, Nevada, Nevada.") It may also involve repeatedly giving the same answer to different questions ("Is your name Mary?" "Yes." "Are you in the hospital?" "Yes." "Are you a table?" "Yes"). Perseveration can include palilalia and logoclonia, and may indicate an organic brain disease such as Parkinson's disease.
• Phonemic paraphasia: Mispronunciation; syllables out of sequence ("I slipped on the lice and broke my arm").{{cite journal |last1=Kurowski |first1=Kathleen |last2=Blumstein |first2=Sheila E. |title=Phonetic basis of phonemic paraphasias in aphasia: Evidence for cascading activation |journal=Cortex |date=February 2016 |volume=75 |pages=193–203 |doi=10.1016/j.cortex.2015.12.005 |pmid=26808838 |pmc=4754157 }}
• Pressured speech:{{cite APA Dictionary |title=Pressured speech |shortlink=pressured-speech |access-date=23 February 2020 }} Rapid speech without pauses, which is difficult to interrupt.
• Referential thinking: Viewing innocuous stimuli as having a specific meaning for the self{{cite journal |last1=Cicero |first1=David C. |last2=Kerns |first2=John G. |title=Unpleasant and pleasant referential thinking: Relations with self-processing, paranoia, and other schizotypal traits |journal=Journal of Research in Personality |date=April 2011 |volume=45 |issue=2 |pages=208–218 |doi=10.1016/j.jrp.2011.02.002 |pmid=26028792 |pmc=4447705 }} ("What's the time?" "It's 7 o'clock. That's my problem").
• Semantic paraphasia: Substitution of inappropriate words ("I slipped on the coat, on the ice I mean, and broke my book").{{cite journal |last1=Buckingham |first1=Hugh W. |last2=Rekart |first2=Deborah M. |title=Semantic paraphasia |journal=Journal of Communication Disorders |date=January 1979 |volume=12 |issue=3 |pages=197–209 |doi=10.1016/0021-9924(79)90041-8 |pmid=438359 }}
• Stilted speech: Speech characterized by words or phrases which are flowery, excessive, and pompous ("The attorney comported himself indecorously").
• Tangential speech: Wandering from the topic and never returning to it, or providing requested information{{cite APA Dictionary |title=Tangential speech |shortlink=tangential-speech |access-date=23 February 2020 }} ("Where are you from?" "My dog is from England. They have good fish and chips there. Fish breathe through gills").
• Thought blocking (also known as deprivation of thought and obstructive thought): An abrupt stop in the middle of a train of thought which may not be able to be continued.{{cite APA Dictionary|title=Blocking|shortlink=blocking|access-date=23 February 2020}}
• Verbigeration:{{harvp | Clinical Manifestations of Psychiatric Disorders | 2017 | loc = THINKING DISTURBANCES, Continuity. }} "Word salad describes the stringing together of words that seem to have no logical association, and verbigeration describes the disappearance of understandable speech, replaced by strings of incoherent utterances." Meaningless, stereotyped repetition of words or phrases which replace understandable speech; seen in schizophrenia.{{harvp | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 | loc = "Chapter 4 Signs and Symptoms in Psychiatry", GLOSSARY OF SIGNS AND SYMPTOMS, p. 32 }}

Psychiatric and psychological glossaries in 2015 and 2017 defined thought disorder' as disturbed thinking or cognition which affects communication, language, or thought content including poverty of ideas, neologisms, paralogia, word salad, and delusions

{{harvp | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | 2017 | loc = Appendix B: Glossary of Psychiatry and Psychology Terms. }} "thought disorder Any disturbance of thinking that affects language, communication, or thought content; the hallmark feature of schizophrenia. Manifestations range from simple blocking and mild circumstantiality to profound loosening of associations, incoherence, and delusions; characterized by a failure to follow semantic and syntactic rules that is inconsistent with the person's education, intelligence, or cultural background."{{cite APA Dictionary|title=Content-thought disorder|shortlink=content-thought-disorder|access-date=23 February 2020}} (disturbances of thought content and form), and suggested the more-specific terms content thought disorder (CTD) and formal thought disorder (FTD). CTD was defined as a TD characterized by multiple fragmented delusions,

{{harvp | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | 2017 | loc = "Appendix B: Glossary of Psychiatry and Psychology Terms" }} "content thought disorder Disturbance in thinking in which a person exhibits delusions that may be multiple, fragmented, and bizarre." and FTD was defined as a disturbance in the form or structure of thinking.{{harvp | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | 2017 | loc = "Appendix B: Glossary of Psychiatry and Psychology Terms" }} "formal thought disorder Disturbance in the form of thought rather than the content of thought; thinking characterized by loosened associations, neologisms, and illogical constructs; thought process is disordered, and the person is defined as psychotic. Characteristic of schizophrenia."{{harvp | APA dictionary of psychology | 2015 | p = 432 }} "formal thought disorder disruptions in the form or structure of thinking. Examples include derailment and tangentiality. It is distinct from TD, in which the disturbance relates to thought content."

The 2013 DSM-5 only used the term FTD, primarily as a synonym for disorganized thinking and speech.{{cite book | ref = {{harvid | DSM-5 | 2013 }} | author = American Psychiatry Association | title = Diagnostic and Statistical Manual of Mental Disorders | date = 2013 | publisher = American Psychiatric Publishing | location = Arlington | isbn = 978-0-89042-555-8 | edition = 5th | url-access = registration | url = https://archive.org/details/diagnosticstatis0005unse }}

• As the proper FTD: "Schizophrenia Spectrum and Other Psychotic Disorders", Key Features That Define the Psychotic Disorders, Disorganized Thinking (Speech), p. 88 "Disorganized thinking (formal thought disorder) is typically inferred from the individual's speech. ..."
• As possibly something else: "Dissociative Disorders", Differential Diagnosis, Psychotic disorders, p. 296 "... Dissociative experiences of identity fragmentation or possession, and of perceived loss of control over thoughts, feelings, impulses, and acts, may be confused with signs of formal thought disorder, such as thought insertion or withdrawal. ..."

This contrasts with the 1992 ICD-10 (which only used the word "thought disorder", always accompanied with "delusion" and "hallucination"){{cite web | date = 1992 | title = The ICD-10 Classification of Mental and Behavioural Disorders: Clinical descriptions and diagnostic guidelines (CDDG) | url =https://www.who.int/entity/classifications/icd/en/bluebook.pdf | publisher = World Health Organization | archive-url = https://web.archive.org/web/20041017011412/http://www.who.int/classifications/icd/en/bluebook.pdf | archive-date = 2004-10-17 | url-status=live }}

• F06.2 Organic delusional [schizophrenia-like] disorder, p.59: Features suggestive of schizophrenia, such as bizarre delusions, hallucinations, or thought disorder, may also be present. ... Diagnostic guidelines ... Hallucinations, thought disorder, or isolated catatonic phenomena may be present. ...
• F20.0 Paranoid schizophrenia, p. 80: ... Thought disorder may be obvious in acute states, but if so it does not prevent the typical delusions or hallucinations from being described clearly. ...
• F20.1 Hebephrenic schizophrenia, p. 81: ... In addition, disturbances of affect and volition, and thought disorder are usually prominent. Hallucinations and delusions may be present but are not usually prominent. ...

and a 2002 medical dictionary which generally defined thought disorders similarly to the psychiatric glossaries{{cite book | ref = {{harvid | The BMA Illustrated Medical Dictionary | 2002 }} | year = 2002 | title = The British Medical Association Illustrated Medical Dictionary | publisher = Dorling Kindersley | isbn = 0-7513-3383-2 | pages = 547 | quote = thought disorders Abnormalities in the structure or content of thought, as reflected in a person's speech, writing, or behaviour. ... }} and used the word in other entries as the ICD-10 did.{{harvp | The BMA Illustrated Medical Dictionary | 2002}}

• p. 470 psychosis: ... Symptoms include delusions, hallucinations, thought disorders, loss of affect, mania, and depression. ...
• p. 499-500 schizophrenia: ... The main symptoms are various forms of delusions such as those of persecution (which are typical of paranoid schizophrenia); hallucinations, which are usually auditory (hearing voices), but which may also be visual or tactile; and thought disorder, leading to impaired concentration and thought processes. ...

A 2017 psychiatric text describing thought disorder as a "disorganization syndrome" in the context of schizophrenia:

{{Blockquote| "Thought disorder" here refers to disorganization of the form of thought and not content. An older use of the term "thought disorder" included the phenomena of delusions and sometimes hallucinations, but this is confusing and ignores the clear differences in the relationships between symptoms that have become apparent over the past 30 years. Delusions and hallucinations should be identified as psychotic symptoms, and thought disorder should be taken to mean formal thought disorders or a disorder of verbal cognition.

| Phenomenology of Schizophrenia (2017), THE SYMPTOMS OF SCHIZOPHRENIA{{cite book | ref = {{harvid | Phenomenology of Schizophrenia | 2017 }} | vauthors = Lewis SF, Escalona R, Keith SJ | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | chapter = 12.2 Phenomenology of Schizophrenia | at = THE SYMPTOMS OF SCHIZOPHRENIA, Disorganization, Thought Disorder. }}

• As quoted in the templated quote.
• "Thought disorder is the most studied form of the disorganization symptoms. It is referred to as "formal thought disorder," or "conceptual disorganization," or as the "disorganization factor" in various studies that examine cognition or subsyndromes in schizophrenia. ..." }}

The text said that some clinicians use the term "formal thought disorder" broadly, referring to abnormalities in thought form with psychotic cognitive signs or symptoms,{{cite book | ref = {{harvid | Clinical Manifestations of Psychiatric Disorders | 2017 }} | vauthors = Matorin AA, Shah AA, Ruiz P | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | chapter = 8 Clinical Manifestations of Psychiatric Disorders | at = THINKING DISTURBANCES, Flow and Form Disturbances. | quote = Although formal thought disorder typically refers to marked abnormalities in the form and flow or connectivity of thought, some clinicians use the term broadly to include any psychotic cognitive sign or symptom. }} and studies of cognition and subsyndromes in schizophrenia may refer to FTD as conceptual disorganization or disorganization factor.

Some disagree:

{{Blockquote| Unfortunately, "thought disorder" is often involved rather loosely to refer to both FTD and delusional content. For the sake of clarity, the unqualified use of the phrase "thought disorder" should be discarded from psychiatric communication. Even the designation "formal thought disorder" covers too wide a territory. It should always be made clear whether one is referring to derailment or loose associations, flight of ideas, or circumstantiality.| The Mental Status Examination, The Medical Basis of Psychiatry (2016){{harvp | The Mental Status Examination | 2016 | loc = 1.6.2. Disturbances in Thinking., pp. 14–15. }}

}}

It was believed that TD occurred only in schizophrenia, but later findings indicate that it may occur in other psychiatric conditions (including mania) and in people without mental illness.{{Cite journal|title=Neural correlates of formal thought disorder: An activation likelihood estimation meta-analysis|year = 2017|doi=10.1002/hbm.23706|pmc=5685170|pmid=28653797|last1 = Wensing|first1 = T.|last2 = Cieslik|first2 = E. C.|last3 = Müller|first3 = V. I.|last4 = Hoffstaedter|first4 = F.|last5 = Eickhoff|first5 = S. B.|last6 = Nickl-Jockschat|first6 = T.|journal = Human Brain Mapping|volume = 38|issue = 10|pages = 4946–4965}} Not all people with schizophrenia have a TD; the condition is not specific to the disease.

When defining thought-disorder subtypes and classifying them as positive or negative symptoms, Nancy Andreasen found{{harvp | Thought Disorder | 2016 | loc = 25.5. Diagnostic and Prognostic Significance of Thought Disorder, pp. 502–503. }} cited

• {{cite journal | vauthors = Andreasen NC | title = Thought, language, and communication disorders. I. Clinical assessment, definition of terms, and evaluation of their reliability | journal = Archives of General Psychiatry | volume = 36 | issue = 12 | pages = 1315–21 | date = November 1979 | pmid = 496551 | doi = 10.1001/archpsyc.1979.01780120045006 }}
• {{cite journal | vauthors = Andreasen NC | title = Thought, language, and communication disorders. II. Diagnostic significance | journal = Archives of General Psychiatry | volume = 36 | issue = 12 | pages = 1325–30 | date = November 1979 | pmid = 496552 | doi = 10.1001/archpsyc.1979.01780120055007 }}
• {{cite book | vauthors = Andreasen NC, Hoffrnann RE, Grove WM | year = 1984 | title = Mapping abnormalities in language and cognition | veditors = Alpert M | work = Controversies in schizophrenia, 1985 | location = New York | publisher = Guilford Press | pages = 199–226 }}

that different subtypes of TD occur at different frequencies in those with mania, depression, and schizophrenia. People with mania have pressured speech as the most prominent symptom, and have rates of derailment, tangentiality, and incoherence as prominent as in those with schizophrenia. They are likelier to have pressured speech, distractibility, and circumstantiality.

People with schizophrenia have more negative TD, including poverty of speech and poverty of content of speech, but also have relatively high rates of some positive TD. Derailment, loss of goal, poverty of content of speech, tangentiality and illogicality are particularly characteristic of schizophrenia.{{cite book | vauthors = Oyebode F | year = 2015 | title = Sims' Symptoms in the Mind: Textbook of Descriptive Psychopathology | edition = 5th | publisher = Saunders Elsevier | isbn = 978-0-7020-5556-0 | chapter = 10 Disorder of Speech and Language | at = Schizophrenic Language Disorder, CLINICAL DESCRIPTION AND THOUGHT DISORDER, p. 167. }} People with depression have relatively-fewer TDs; the most prominent are poverty of speech, poverty of content of speech, and circumstantiality. Andreasen noted the diagnostic usefulness of dividing the symptoms into subtypes; negative TDs without full affective symptoms suggest schizophrenia.{{cite book | veditors = Fatemi SH, Clayton PJ | year = 2016 | title = The Medical Basis of Psychiatry | edition = 4th | location = New York | publisher = Springer Science+Business Media | isbn = 978-1-4939-2528-5 | doi = 10.1007/978-1-4939-2528-5 | vauthors = Coryell W, Clayton PJ | chapter = 4 Bipolar Illness | at = 4.7. Clinical Picture, 4.7.2. Symptoms, p. 59.}}

She also cited the prognostic value of negative-positive-symptom divisions. In manic patients, most TDs resolve six months after evaluation; this suggests that TDs in mania, although as severe as in schizophrenia, tend to improve. In people with schizophrenia, however, negative TDs remain after six months and sometimes worsen; positive TDs somewhat improve. A negative TD is a good predictor of some outcomes; patients with prominent negative TDs are worse in social functioning six months later. More prominent negative symptoms generally suggest a worse outcome; however, some people may do well, respond to medication, and have normal brain function. Positive symptoms vary similarly.{{harvp | Thought Disorder | 2016 | loc = 25.6. Relationship Between Thought Disorders and Other Symptoms of Schizophrenia., pp. 503–504. }}

A prominent TD at illness onset suggests a worse prognosis, including:{{Div col | colwidth = 30em}}

• illness begins earlier
• increased risk of hospitalization
• decreased functional outcomes
• increased disability rates
• increased inappropriate social behaviors{{Div col end}}

TD which is unresponsive to treatment predicts a worse illness course. In schizophrenia, TD severity tends to be more stable than hallucinations and delusions. Prominent TDs are more unlikely to diminish in middle age, compared with positive symptoms. Less-severe TD may occur during the prodromal and residual periods of schizophrenia.{{harvp | DSM-5 | 2013 | loc = Schizophrenia Spectrum and Other Psychotic Disorders, Key Features That Define the Psychotic Disorders, Disorganized Thinking (Speech), p. 88. }} Treatment for thought disorder may include psychotherapy, such as cognitive behavior therapy (CBT), and psychotropic medications.{{Cite web|title=Thought Disorder {{!}} Johns Hopkins Psychiatry Guide|url=https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_Psychiatry_Guide/787025/all/Thought_Disorder?refer=true|access-date=2021-07-15|website=www.hopkinsguides.com|language=en}}

The DSM-5 includes delusions, hallucinations, disorganized thought process (formal thought disorder), and disorganized or abnormal motor behavior (including catatonia) as key symptoms of psychosis. Schizophrenia-spectrum disorders such as schizoaffective disorder and schizophreniform disorder typically consist of prominent hallucinations, delusions and FTD; the latter presents as severely disorganized, bizarre, and catatonic behavior. Psychotic disorders due to medical conditions and substance use typically consist of delusions and hallucinations. The rarer delusional disorder and shared psychotic disorder typically present with persistent delusions.{{cite book | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | vauthors = Ivleva EI, Tamminga CA | chapter = 12.16 Psychosis as a Defining Dimension in Schizophrenia | at = DSM-5: AN UPDATED DEFINITION OF PSYCHOSIS}} FTDs are commonly found in schizophrenia and mood disorders, with poverty of speech content more common in schizophrenia.{{cite book | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | vauthors = Akiskal HS | chapter = 13.4 Mood Disorders: Clinical Features | at = BIPOLAR DISORDERS, Bipolar I Disorder, Acute Mania.}}

Psychoses such as schizophrenia and bipolar mania are distinguishable from malingering, when an individual fakes illness for other gains, by clinical presentations; malingerers feign thought content with no irregularities in form such as derailment or looseness of association. Negative symptoms, including alogia, may be absent, and chronic thought disorder is typically distressing.{{cite book | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | vauthors = Ninivaggi FJ | chapter = 28.1 Malingering | at = CLINICAL PRESENTATIONS OF MALINGERING, Psychological Symptomatology: Clinical Presentations, Psychosis.}}

Autism spectrum disorders (ASD) whose diagnosis requires the onset of symptoms before three years of age can be distinguished from early-onset schizophrenia; schizophrenia under age 10 is extremely rare, and ASD patients do not display FTDs.{{cite book | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer | vauthors = Sikich L, Chandrasekhar T | chapter = 53 Early-Onset Psychotic Disorders | at = DIFFERENTIAL DIAGNOSIS, Autism Spectrum Disorders}} However, it has been suggested that individuals with ASD display language disturbances like those found in schizophrenia; a 2008 study found that children and adolescents with ASD showed significantly more illogical thinking and loose associations than control subjects. The illogical thinking was related to cognitive functioning and executive control; the loose associations were related to communication symptoms and parent reports of stress and anxiety.{{cite journal | vauthors = Solomon M, Ozonoff S, Carter C, Caplan R | title = Formal thought disorder and the autism spectrum: relationship with symptoms, executive control, and anxiety | journal = Journal of Autism and Developmental Disorders | volume = 38 | issue = 8 | pages = 1474–84 | date = September 2008 | pmid = 18297385 | pmc = 5519298 | doi = 10.1007/s10803-007-0526-6 }}

Rorschach tests have been useful for assessing TD in disturbed patients.{{cite journal |last1=Hart |first1=Mara |last2=Lewine |first2=Richard R. J. |title=Rethinking Thought Disorder |journal=Schizophrenia Bulletin |date=May 2017 |volume=43 |issue=3 |pages=514–522 |doi=10.1093/schbul/sbx003 |pmid=28204762 |pmc=5464106 }} A series of inkblots are shown, and patient responses are analyzed to determine disturbances of thought. The nature of the assessment offers insight into the cognitive processes of another, and how they respond to equivocal stimuli.{{cite book |last1=Rapaport |first1=David |last2=Schafer |first2=Roy |last3=Gill |first3=Merton Max |title=Diagnostic Psychological Testing: The Theory, Statistical Evaluation, and Diagnostic Application of a Battery of Tests |date=1946 |publisher=Year book publishers |oclc=426466259 }}{{pn|date=September 2024}} Hermann Rorschach developed this test to diagnose schizophrenia after realizing that people with schizophrenia gave drastically different interpretations of Klecksographie inkblots from others whose thought processes were considered normal,{{Cite news|date=2012-07-24|title=What's behind the Rorschach inkblot test?|language=en-GB|work=BBC News|url=https://www.bbc.com/news/magazine-18952667|access-date=2021-07-15}} and it has become one of the most widely used assessment tools for diagnosing TDs.

The Thought Disorder Index (TDI), also known as the Delta Index, was developed to help further determine the severity of TD in verbal responses. TDI scores are primarily derived from verbally-expressed interpretations of the Rorschach test, but TDI can also be used with other verbal samples (including the Wechsler Adult Intelligence Scale). TDI has a twenty-three-category scoring index; each category scores the level of severity on a scale from 0 to 1, with .25 being mild and 1.00 being most severe (0.25, 0.50, 0.75, 1.00).

TD has been criticized as being based on circular or incoherent definitions.Bentall, R. (2003) Madness explained: Psychosis and Human Nature. London: Penguin Books Ltd. {{ISBN|0-7139-9249-2}}{{pn|date=September 2024}}{{Request quotation | date=February 2020}} Symptoms of TD are inferred from disordered speech, based on the assumption that disordered speech arises from disordered thought. Although TD is typically associated with psychosis, similar phenomena can appear in different disorders and leading to misdiagnosis.{{cite journal |last1=Tufan |first1=Ali Evren |last2=Bilici |first2=Rabia |last3=Usta |first3=Genco |last4=Erdoğan |first4=Ayten |title=Mood disorder with mixed, psychotic features due to vitamin b12 deficiency in an adolescent: case report |journal=Child and Adolescent Psychiatry and Mental Health |date=December 2012 |volume=6 |issue=1 |page=25 |doi=10.1186/1753-2000-6-25 |pmid=22726236 |pmc=3404901 |doi-access=free }}

A criticism related to the separation of symptoms of schizophrenia into negative or positive symptoms, including TD, is that it oversimplifies the complexity of TD and its relationship to other positive symptoms. Factor analysis has found that negative symptoms tend to correlate with one another, but positive symptoms tend to separate into two groups.{{harvp | Thought Disorder | 2016 | loc = 25.6. Relationship Between Thought Disorders and Other Symptoms of Schizophrenia., pp. 503–504. }} cited

• {{cite journal | vauthors = Arndt S, Alliger RJ, Andreasen NC | title = The distinction of positive and negative symptoms. The failure of a two-dimensional model | journal = The British Journal of Psychiatry | volume = 158 | pages = 317–22 | date = March 1991 | pmid = 2036528 | doi = 10.1192/bjp.158.3.317 | s2cid = 41383575 }}
• {{cite journal | vauthors = Bilder RM, Mukherjee S, Rieder RO, Pandurangi AK | title = Symptomatic and neuropsychological components of defect states | journal = Schizophrenia Bulletin | volume = 11 | issue = 3 | pages = 409–19 | year = 1985 | pmid = 4035304 | doi = 10.1093/schbul/11.3.409 | doi-access = free }}
• {{cite journal | vauthors = Liddle PF | title = The symptoms of chronic schizophrenia. A re-examination of the positive-negative dichotomy | journal = The British Journal of Psychiatry | volume = 151 | pages = 145–51 | date = August 1987 | pmid = 3690102 | doi = 10.1192/bjp.151.2.145 | s2cid = 15270392 }}

The three clusters became known as negative symptoms, psychotic symptoms, and disorganization symptoms. Alogia, a TD traditionally classified as a negative symptom, can be separated into two types: poverty of speech content (a disorganization symptom) and poverty of speech, response latency, and thought blocking (negative symptoms).{{cite journal | vauthors = Miller DD, Arndt S, Andreasen NC | title = Alogia, attentional impairment, and inappropriate affect: their status in the dimensions of schizophrenia | journal = Comprehensive Psychiatry | volume = 34 | issue = 4 | pages = 221–6 | year = 2004 | pmid = 8348799 | doi = 10.1016/0010-440X(93)90002-L }}

Positive-negative-symptom diametrics, however, may enable a more accurate characterization of schizophrenia.{{harvp | Phenomenology of Schizophrenia | 2017 | loc = THE SYMPTOMS OF SCHIZOPHRENIA, Negative Symptoms. }} "The two-syndrome concept as formulated by T. J. Crow was especially important in spurring research into the nature of negative symptoms ... but this does not diminish the creative efforts that led to these scales or importance of these scales for research. In fact, it was only through careful analysis of the structure of symptoms in these scales that a more accurate characterization of the phenomenology of schizophrenia was possible."

• Aphasia
• Auditory processing disorder
• Emil Kraepelin's dream speech
• Speech–language pathology

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• {{cite book | ref = {{harvid | APA dictionary of psychology |2015 }} | veditors = VandenBos GR | year = 2015 | edition = 2nd | title = APA dictionary of psychology | location = Washington, DC | publisher = American Psychological Association | isbn = 978-1-4338-1944-5 | doi = 10.1037/14646-000| url = https://hal.science/hal-04340738/file/fpubh-11-1296609%20%281%29.pdf }}
• {{cite book | ref = {{harvid | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | 2017 }} | veditors = Sadock VA, Sadock BJ, Ruiz P | year = 2017 | title = Kaplan & Sadock's Comprehensive Textbook of Psychiatry | edition = 10th | isbn = 978-1-4511-0047-1 | publisher = Wolters Kluwer}}
• {{cite book | ref = {{harvid | Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | 2008 }} | vauthors = Sadock BJ, Sadock VA | title = Kaplan and Sadock's Concise Textbook of Clinical Psychiatry | year = 2008 | publisher = Lippincott Williams & Wilkins | isbn = 9780781787468 }}
• {{cite book | ref = {{harvid | Thought Disorder | 2016 }} | veditors = Fatemi SH, Clayton PJ | year = 2016 | title = The Medical Basis of Psychiatry | edition = 4th | location = New York | publisher = Springer Science+Business Media | isbn = 978-1-4939-2528-5 | doi = 10.1007/978-1-4939-2528-5 | vauthors = Andreasen NC | chapter = 25 Thought Disorder | pages = 497–505 }}
• {{cite book| vauthors = McKenna PJ, Oh TM |title=Schizophrenic Speech: Making Sense of Bathroots and Ponds that Fall in Doorways|year=2005|publisher=Cambridge University Press|isbn=978-0-521-81075-3}}

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Category:Psychosis

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