clouding of consciousness

The term clouding of consciousness has always denoted the main pathogenetic feature of delirium since physician Georg Greiner{{cite book |author=Georg Friedrich Christoph Greiner|title=Der Traum und das fieberhafte Irreseyn: ein physiologisch-psychologischer Versuch|publisher=F. A Brockhaus|year=1817|oclc=695736431|url=https://books.google.com/books?id=RcIAAAAAcAAJ&pg=PP5}} pioneered the term ({{lang|de|Verdunkelung des Bewusstseins}}) in 1817.{{cite book |author1=Augusto Caraceni |author2=Luigi Grassi |title=Delirium: Acute Confusional States in Palliative Medicine |publisher=Oxford University Press |year=2011 |page=2 |url=https://books.google.com/books?id=qiUfHyoC_zUC&q=Verdunkelung+des+Bewusstseins&pg=PA2 |isbn=978-0199572052}} The Diagnostic and Statistical Manual of Mental Disorders (DSM) has historically used the term in its definition of delirium.{{cite book |author1=George Stein |author2=Greg Wilkinson |title=Seminars in General Adult Psychiatry |publisher=RCPsych Publications|date=2007 |pages=490|url=https://books.google.com/books?id=6PGzHFuS1xkC&q=%22clouding+of+consciousness%22&pg=PA490 |isbn=978-1904671442}} The DSM-III-R and the DSM-IV replaced "clouding of consciousness" with "disturbance of consciousness" to make it easier to operationalize, but it is still fundamentally the same thing.{{cite journal |author1=Dan G. Blazer |author2=Adrienne O. van Nieuwenhuizen |journal=Curr Opin Psychiatry |volume=25 |issue=3 |title=Evidence for the Diagnostic Criteria of Delirium |year=2012 |pages=239–243 | url=http://www.medscape.com/viewarticle/761823_2 |doi=10.1097/yco.0b013e3283523ce8|pmid=22449764 |s2cid=39516431 |url-access=subscription }} Clouding of consciousness may be less severe than delirium on a spectrum of abnormal consciousness.{{cite book |author1=Anthony David |author2=Simon Fleminger |author3=Michael Kopelman |author4=Simon Lovestone |author5=John Mellers |title=Lishman's Organic Psychiatry: A Textbook of Neuropsychiatry |publisher=John Wiley & Sons |date=April 2012 |pages=5 |url=https://books.google.com/books?id=ohG6I1C_NeAC&q=%22clouding+of+consciousness+denotes+the+mildest+stage%22&pg=PA5 |isbn=978-0470675076}}{{cite book |author=Fang Gao Smith|title=Core Topics in Critical Care Medicine|publisher=Cambridge University Press|year= 2010 |page=312 |url=https://books.google.com/books?id=7ruHkxLgIQ8C&q=%22clouding+of+consciousness+very+mild+form+of+mental+status%22&pg=PA312 |isbn=978-1139489683 }} Clouding of consciousness may be synonymous with subsyndromal delirium.{{cite journal |author=Sébastien Ouimet |journal=Intensive Care Med |volume=33 |title=Subsyndromal delirium in the ICU: evidence for a disease spectrum |year=2007 |pages=1007–1013 |doi=10.1007/s00134-007-0618-y |pmid=17404704 |last2=Riker |first2=R |last3=Bergeron |first3=N |last4=Cossette |first4=M |last5=Kavanagh |first5=B |last6=Skrobik |first6=Y |issue=6 |s2cid=20565946 |display-authors=etal}}

Subsyndromal delirium differs from normal delirium by being overall less severe, lacking acuteness in onset and duration, having a relatively stable sleep-wake cycle, and having relatively stable motor alterations.{{cite journal |author=David Meagher|journal=The British Journal of Psychiatry|volume=200|doi=10.1192/bjp.bp.111.095273|title=Features of subsyndromal and persistent delirium |year=2012 |pages=37–44|last2=Adamis |first2=D. |last3=Trzepacz |first3=P. |last4=Leonard |first4=M. |pmid=22075650 |issue=1|display-authors=etal|doi-access=free }} Subsyndromal delirium's significant clinical features are inattention, thought process abnormalities, comprehension abnormalities, and language abnormalities. Delirium's full clinical manifestations may never be reached. Among intensive care unit patients, subsyndromal subjects were as likely to survive as patients with a Delirium Screening Checklist score of 0, but required extended care at rates greater than 0-scoring patients (although lower rates than those with full ICU delirium) or have a decreased post-discharge level of functional independence vs. the general population but still more independence than full delirium.

In clinical practice, no standard test is exclusive and specific; therefore, the diagnosis depends on the physician's subjective impression. The DSM-IV-TR instructs clinicians to code subsyndromal delirium presentations under the miscellaneous category "cognitive disorder not otherwise specified".{{cite book |author1=Augusto Caraceni |author2=Luigi Grassi |title=Delirium: Acute Confusional States in Palliative Medicine |publisher=Oxford University Press |year=2011 |page=11 |url=https://books.google.com/books?id=qiUfHyoC_zUC&q=%22subsyndromal+presentations+need+to+be+carefully+assessed%22&pg=PA11 |isbn=978-0199572052}}

The conceptual model of clouding of consciousness in psychopathology is that of a part of the brain regulating the "overall level" of consciousness, which is responsible for awareness of oneself and of the environment.{{cite book |author1=Augusto Caraceni |author2=Luigi Grassi |title=Delirium: Acute Confusional States in Palliative Medicine |publisher=Oxford University Press |year=2011 |pages=19–21 |url=https://books.google.com/books?id=qiUfHyoC_zUC&q=%22level+of+consciousness+and+the+content+of+consciousness%22&pg=PA19 |isbn=978-0199572052}} Various etiologies disturb this regulating part of the brain, which in turn disturbs the "overall level" of consciousness.{{cite book |author=Yudofsky & Hales |title=The American Psychiatric Publishing textbook of neuropsychiatry and behavioral neurosciences |publisher=American Psychiatric Pub |year=2008 |page=477 |url=https://books.google.com/books?id=f5BEk-6yO_4C&q=%22funnel+into+a+final+common+neural+pathway%22&pg=PA477 |isbn=978-1585622399}} This system of a sort of general activation of consciousness is called "arousal" or "wakefulness".

It is not necessarily accompanied by drowsiness.{{cite book |author1=Roger A. MacKinnon |author2=Robert Michels |author3=Peter J. Buckley |title=The Psychiatric Interview in Clinical Practice |edition =2nd|publisher=American Psychiatric Publishing, Inc. |year=2006 |pages=462–464 }} Patients may be awake (not sleepy) yet still have a clouded consciousness (disorder of wakefulness).{{cite book |title=Plum and Posner's diagnosis of stupor and coma |publisher=Oxford University Press |year=2007 |page=8 |url=https://books.google.com/books?id=Otivdh2ZoVwC&q=%22However%2C+when+awakened%2C+consciousness+is+clearly+clouded%22&pg=PA8 |isbn=978-0198043362 }} Paradoxically, affected individuals say that they are "awake but, in another way, not".{{cite journal |author1=G Sorensen Duppils |author2=K Wikblad |journal=Journal of Clinical Nursing |volume=16|issue=5|title=Patients' experiences of being delirious|date=May 2007|pages=810–818 |doi=10.1111/j.1365-2702.2006.01806.x|pmid=17462032}} Lipowski points out that decreased "wakefulness" as used here is not exactly synonymous with drowsiness. One is a stage on the way to coma, the other on the way to sleep, which is very different.{{cite journal |author=Lipowski ZJ.|journal=Journal of Nervous and Mental Disease |volume=145 |issue=3 |title=Delirium, clouding of consciousness and confusion|year=1967|pages=227–255 |doi=10.1097/00005053-196709000-00006 |pmid=4863989}}{{cite book |title=Organic Psychiatry: The Psychological Consequences of Cerebral Disorder|author=William Alwyn Lishman |publisher=John Wiley & Sons |year=1998 |page=4 }}

The affected person has a sensation of mental clouding described in the patient's own words as "foggy". One patient said, "I thought it became like misty, in some way... the outlines were sort of fuzzy". Others may describe a "spaced-out" feeling.{{cite book |author=Fred Ovsiew, M.D. |title=Neuropsychiatry and Mental Health Services |publisher=American Psychiatric Press, Inc. |year=1999 |page=170|url=https://books.google.com/books?id=l6giB-cCvl0C&q=%22level+of+consciousness+that+may+range+from+a+%22spaced+out%22+feeling%22&pg=PA170 |isbn=0880487305 }} Affected people compare their overall experience to that of a dream, because, as in a dream, consciousness, attention, orientation to time and place, perceptions, and awareness are disturbed.{{cite journal | title= Remembering delirium | author = Simon Fleminger | journal= The British Journal of Psychiatry | volume= 180 | pages= 4–5 | year= 2002 | doi= 10.1192/bjp.180.1.4 | pmid= 11772842 | issue=1| doi-access= free }} Barbara Schildkrout, a clinical instructor in psychiatry at the Harvard Medical School, described her subjective experience of clouding of consciousness, which she also called "mental fog", after taking a single dose of chlorpheniramine (an antihistamine for her allergy to cottonwood) on a cross-country road trip. She described feeling "out of it" and being in a "dreamy state". She described a sense of not trusting her own judgment and a dulled awareness, not knowing how much time had passed. Clouding of consciousness is not the same thing as depersonalization, though people affected by both compare their experience to that of a dream. Psychometric tests produce little evidence of a relationship between clouding of consciousness and depersonalization.{{cite journal |last1=Sedman |first1=G. |title=Theories of Depersonalization: A Re-appraisal |journal=British Journal of Psychiatry |date=July 1970 |volume=117 |issue=536 |pages=1–14 |doi=10.1192/s0007125000192104 |pmid=4920886 |s2cid=246610704 }}

Brain fog may affect performance on virtually any cognitive task. As one author put it, "It should be apparent that cognition is not possible without a reasonable degree of arousal." Cognition includes perception, memory, learning, executive functions, language, constructive abilities, voluntary motor control, attention, and mental speed. Brain fog's most significant clinical features are inattention, thought process abnormalities, comprehension abnormalities, and language abnormalities. The extent of the impairment is variable because inattention may impair several cognitive functions. Affected people may complain of forgetfulness, being "confused", or being "unable to think straight".{{cite book |author1=John Noble |author2=Harry L. Greene |title=Textbook of Primary Care Medicine |publisher=Mosby|year=1996|page=1325}} Despite the similarities, subsyndromal delirium is not the same thing as mild cognitive impairment; the fundamental difference is that mild cognitive impairment is a dementia-like impairment, which does not involve a disturbance in arousal (wakefulness).{{cite book |title=Plum and Posner's diagnosis of stupor and coma |publisher=Oxford University Press |year=2007 |page=7 |url=https://books.google.com/books?id=eDcWsh3FCFQC&q=%22not+usually+accompanied+by+a+reduction+in+arousal%22&pg=PT23 |isbn=978-0199886531}}

The term "brain fog" is used to represent a subjective condition of perceived cognitive impairment. It is defined as "a phenomenon of fluctuating states of perceived cognitive dysfunction that could have implications in the functional application of cognitive skills in people's participation in daily activities". Brain fog is a common symptom in many illnesses where chronic pain is a major component.{{Cite journal |last1=Dass |first1=Ronessa |last2=Kalia |first2=Mohini |last3=Harris |first3=Jocelyn |last4=Packham |first4=Tara |date=2023-12-31 |title=Understanding the Experience and Impacts of Brain Fog in Chronic Pain: A Scoping Review |journal=Canadian Journal of Pain |language=en |volume=7 |issue=1 |doi=10.1080/24740527.2023.2217865 |issn=2474-0527 |pmc=10334862 |pmid=37441085}} Brain fog affects 15% to 40% of those with chronic pain as their major illness.{{Cite journal |last1=Kucyi |first1=Aaron |last2=Davis |first2=Karen D. |date=2015 |title=The dynamic pain connectome |url=https://linkinghub.elsevier.com/retrieve/pii/S0166223614002173 |journal=Trends in Neurosciences |language=en |volume=38 |issue=2 |pages=86–95 |doi=10.1016/j.tins.2014.11.006|pmid=25541287 |s2cid=745129 |url-access=subscription }} In such illnesses, pain processing may use up resources, decreasing the brain's ability to think effectively.

Many people with fibromyalgia experience cognitive problems{{cite journal |last1=Glass |first1=Jennifer M. |title=Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: New trends and future directions |journal=Current Rheumatology Reports |date=November 2006 |volume=8 |issue=6 |pages=425–429 |doi=10.1007/s11926-006-0036-0 |pmid=17092441 |s2cid=27103590 }} (known as "fibrofog" or "brainfog"), which may involve impaired concentration,{{cite journal |last1=Arnold |first1=Lesley M. |last2=Bennett |first2=Robert M. |last3=Crofford |first3=Leslie J. |last4=Dean |first4=Linda E. |last5=Clauw |first5=Daniel J. |last6=Goldenberg |first6=Don L. |last7=Fitzcharles |first7=Mary-Ann |last8=Paiva |first8=Eduardo S. |last9=Staud |first9=Roland |last10=Sarzi-Puttini |first10=Piercarlo |last11=Buskila |first11=Dan |last12=Macfarlane |first12=Gary J. |title=AAPT Diagnostic Criteria for Fibromyalgia |journal=The Journal of Pain |date=June 2019 |volume=20 |issue=6 |pages=611–628 |doi=10.1016/j.jpain.2018.10.008 |pmid=30453109 |s2cid=53872511 |doi-access=free |hdl=2434/632765 |hdl-access=free }}{{cite journal |last1=Williams |first1=David A |last2=Clauw |first2=Daniel J |last3=Glass |first3=Jennifer M |title=Perceived Cognitive Dysfunction in Fibromyalgia Syndrome |journal=Journal of Musculoskeletal Pain |date=April 2011 |volume=19 |issue=2 |pages=66–75 |doi=10.3109/10582452.2011.558989 |s2cid=144893303 }}{{MEDRS|date=March 2022}}{{MEDRS|date=March 2022}} {{cite journal |last1=Leavitt |first1=Frank |last2=Katz |first2=Robert S. |last3=Mills |first3=Megan |last4=Heard |first4=Amy R. |title=Cognitive and Dissociative Manifestations in Fibromyalgia |journal=JCR: Journal of Clinical Rheumatology |date=April 2002 |volume=8 |issue=2 |pages=77–84 |doi=10.1097/00124743-200204000-00003 |pmid=17041327 |s2cid=12352666 }} problems with short{{cite journal |last1=Buskila |first1=Dan |last2=Cohen |first2=Hagit |title=Comorbidity of fibromyalgia and psychiatric disorders |journal=Current Pain and Headache Reports |date=October 2007 |volume=11 |issue=5 |pages=333–338 |doi=10.1007/s11916-007-0214-4 |pmid=17894922 |s2cid=28038437 }}- and long-term memory, short-term memory consolidation, working memory,{{cite journal |last1=Mercado |first1=Francisco |last2=Ferrera |first2=David |last3=Fernandes-Magalhaes |first3=Roberto |last4=Peláez |first4=Irene |last5=Barjola |first5=Paloma |title=Altered Subprocesses of Working Memory in Patients with Fibromyalgia: An Event-Related Potential Study Using N -Back Task |journal=Pain Medicine |date=2 March 2022 |volume=23 |issue=3 |pages=475–487 |doi=10.1093/pm/pnab190 |pmid=34145889 }} impaired speed of performance, inability to multitask, cognitive overload, and diminished attention span. About 75% of fibromyalgia patients report significant problems with concentration, memory, and multitasking.{{cite journal |last1=Bell |first1=Tyler |last2=Trost |first2=Zina |last3=Buelow |first3=Melissa T. |last4=Clay |first4=Olivio |last5=Younger |first5=Jarred |last6=Moore |first6=David |last7=Crowe |first7=Michael |title=Meta-analysis of cognitive performance in fibromyalgia |journal=Journal of Clinical and Experimental Neuropsychology |date=9 August 2018 |volume=40 |issue=7 |pages=698–714 |doi=10.1080/13803395.2017.1422699 |pmid=29388512 |pmc=6151134 }} A 2018 meta-analysis found that the largest differences between fibromyalgia patients and healthy subjects were for inhibitory control, memory, and processing speed. Many of these are also common symptoms of ADHD (attention deficit hyperactivity disorder), and studies have linked the two conditions, to the point that a fibromyalgia diagnosis has been proposed as an indication to screen for ADHD.{{cite journal |last1=Bou Khalil |first1=Rami |last2=Khoury |first2=Elie |last3=Richa |first3=Sami |title=The Comorbidity of Fibromyalgia Syndrome and Attention Deficit and Hyperactivity Disorder from a Pathogenic Perspective |journal=Pain Medicine |date=1 September 2018 |volume=19 |issue=9 |pages=1705–1709 |doi=10.1093/pm/pny142 |pmid=30053155 |doi-access=free }}{{cite journal |last1=Yilmaz |first1=Ertan |last2=Tamam |first2=Lut |title=Attention-deficit hyperactivity disorder and impulsivity in female patients with fibromyalgia |journal=Neuropsychiatric Disease and Treatment |date=24 July 2018 |volume=14 |pages=1883–1889 |doi=10.2147/NDT.S159312 |pmid=30100723 |pmc=6063452 |doi-access=free }}{{cite web | url=https://www.ajmc.com/view/study-suggests-screening-patients-with-fibromyalgia-syndrome-for-adhd- | title=Study Suggests Screening Patients with Fibromyalgia Syndrome for ADHD | date=28 December 2017 }} It is alternatively hypothesized that the increased pain compromises attention systems, resulting in cognitive problems.

In chronic fatigue syndrome, also known as myalgic encephalomyelitis, the CDC's recommended criteria for diagnosis{{cite web |title=Symptoms of ME/CFS {{!}} Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) |url=https://www.cdc.gov/me-cfs/symptoms-diagnosis/symptoms.html |website=CDC |date=9 February 2021 }} include that one of the following symptoms must be present:

• Problems with thinking and memory (cognitive dysfunction, sometimes described as "brain fog")
• While standing or sitting upright, lightheadedness, dizziness, weakness, fainting, or vision changes may occur (orthostatic intolerance)

Lyme disease's neurologic syndrome, called Lyme encephalopathy, is associated with subtle memory and cognitive difficulties, among other issues.{{cite journal |last1=Bratton |first1=Robert L. |last2=Whiteside |first2=John W. |last3=Hovan |first3=Michael J. |last4=Engle |first4=Richard L. |last5=Edwards |first5=Frederick D. |title=Diagnosis and Treatment of Lyme Disease |journal=Mayo Clinic Proceedings |date=May 2008 |volume=83 |issue=5 |pages=566–571 |doi=10.4065/83.5.566 |pmid=18452688 |doi-access=free }} Lyme can cause a chronic encephalomyelitis that resembles multiple sclerosis. It may be progressive and can involve cognitive impairment, migraines, balance problems, and other symptoms.{{citation needed|date=June 2022}}

Brain fog is a common symptom of hypothyroidism, with a survey showing that 79.2% of those with the condition reported experiencing brain fog to some extent, either selecting the option for "frequently" or "all the time".{{cite journal |last1=Ettleson |first1=Matthew D.|last2=Raine |first2=Ava |last3=Batistuzzo|first3=Alice|last4=Batista|first4=Samuel P.|last5=McAninch|first5=Elizabeth|last6=Teixeira|first6=Maria Cristina T.V.|last7=Jonklaas|first7=Jacqueline |last8=Laiteerapong|first8=Neda|last9=Ribeiro|first9=Miriam O.|last10=Bianco|first10=Antonio C.|date=March 2022 |title=Brain Fog in Hypothyroidism: Understanding the Patient's Perspective |journal=Endocrine Practice|volume=28 |issue=3 |pages=257–264 |doi=10.1016/j.eprac.2021.12.003 |pmc=8901556|pmid= 34890786}} While it is unclear how the disease leads to brain fog, proper treatment with levothyroxine has been shown to reduce cognitive impairment.{{cite journal |last1=Smith|first1=Jeremy W.|last2=Evans|first2=A Tudor|last3=Costall|first3=B|last4=Smythe|first4=James W.|date=January 2002 |title=Thyroid hormones, brain function and cognition: a brief review |url=https://pubmed.ncbi.nlm.nih.gov/11835983/ |journal=Neuroscience & Biobehavioral Reviews |volume=26 |issue=1 |pages= 045–60|doi=10.1016/s0149-7634(01)00037-9 |pmid= 11835983}}

The concept of sluggish cognitive tempo was implicated in the expression of brain fog symptoms.{{cite book |last1=Barkley |first1=Russell A. |url=https://books.google.com/books?id=BSLF7yueqoUC&pg=PA150 |title=Taking Charge of ADHD: The Complete, Authoritative Guide for Parents |date=2013 |publisher=Guilford Publications |isbn=978-1-4625-0789-4 |page=150}}

Patients recovering from COVID-19 report experiencing brain fog, which can reflect a wide variety of neurological and psychological symptoms linked to COVID-19.{{cite journal |last1=Koralnik |first1=Igor J. |last2=Tyler |first2=Kenneth L. |date=July 2020 |title=COVID-19: A Global Threat to the Nervous System |journal=Annals of Neurology |volume=88 |issue=1 |pages=1–11 |doi=10.1002/ana.25807 |pmc=7300753 |pmid=32506549}}

Brain fog and other neurological symptoms may also result from mold exposure.{{cite journal | vauthors = Empting LD | title = Neurologic and neuropsychiatric syndrome features of mold and mycotoxin exposure | journal = Toxicol Ind Health | volume = 25 | issue = 9–10 | pages = 577–581 | date = 2009 | pmid = 19854819 | doi = 10.1177/0748233709348393 | bibcode = 2009ToxIH..25..577E | s2cid = 27769836 | url = }}{{cite journal | vauthors = Valtonen V | title = Clinical Diagnosis of the Dampness and Mold Hypersensitivity Syndrome: Review of the Literature and Suggested Diagnostic Criteria | journal = Front Immunol | volume = 8 | issue = | pages = 951 | date = 2017 | pmid = 28848553 | pmc = 5554125 | doi = 10.3389/fimmu.2017.00951 | url = | doi-access = free }}{{cite journal | vauthors = Harding CF, Liao D, Persaud R, DeStefano RA, Page KG, Stalbow LL, Roa T, Ford JC, Goman KD, Pytte CL | title = Differential effects of exposure to toxic or nontoxic mold spores on brain inflammation and Morris water maze performance | journal = Behav Brain Res | volume = 442 | issue = | pages = 114294 | date = March 2023 | pmid = 36638914 | doi = 10.1016/j.bbr.2023.114294 | pmc = 10460635 | url = }}{{cite journal | vauthors = Ratnaseelan AM, Tsilioni I, Theoharides TC | title = Effects of Mycotoxins on Neuropsychiatric Symptoms and Immune Processes | journal = Clin Ther | volume = 40 | issue = 6 | pages = 903–917 | date = June 2018 | pmid = 29880330 | doi = 10.1016/j.clinthera.2018.05.004 | url = | doi-access = free }}{{cite journal | vauthors = Harding CF, Pytte CL, Page KG, Ryberg KJ, Normand E, Remigio GJ, DeStefano RA, Morris DB, Voronina J, Lopez A, Stalbow LA, Williams EP, Abreu N | title = Mold inhalation causes innate immune activation, neural, cognitive and emotional dysfunction | journal = Brain Behav Immun | volume = 87 | issue = | pages = 218–228 | date = July 2020 | pmid = 31751617 | pmc = 7231651 | doi = 10.1016/j.bbi.2019.11.006 | url = }} This may be due to mycotoxin exposure and consequent innate immune system activation and inflammation, including in the central nervous system.{{cite journal | last1 = Viljoen | first1 = Margaretha | last2 = Claassen | first2 = Nicolaas | title = Pathophysiological aspects of exposure to dampness-associated indoor mould and mycotoxins: A mini-overview | journal = Journal of Hazardous Materials Advances | date = February 2023 | volume = 9 | page = 100228 | issn = 2772-4166 | doi = 10.1016/j.hazadv.2022.100228 | pmid = | url = | doi-access = free | bibcode = 2023JHzMA...900228V | hdl = 2263/95331 | hdl-access = free }} But adverse neurological health effects of mold exposure are controversial due to inadequate research and data, and more research is needed in this area.{{cite journal | vauthors = Rudert A, Portnoy J | title = Mold allergy: is it real and what do we do about it? | journal = Expert Rev Clin Immunol | volume = 13 | issue = 8 | pages = 823–835 | date = August 2017 | pmid = 28453304 | doi = 10.1080/1744666X.2017.1324298 | s2cid = 4755858 | url = }}{{cite journal | vauthors = Borchers AT, Chang C, Eric Gershwin M | title = Mold and Human Health: a Reality Check | journal = Clin Rev Allergy Immunol | volume = 52 | issue = 3 | pages = 305–322 | date = June 2017 | pmid = 28299723 | doi = 10.1007/s12016-017-8601-z | s2cid = 25709697 | url = }}

{{Portal|Psychiatry|Psychology|Medicine}}

{{div col|colwidth=20em}}

• Altered level of consciousness
• Cannabis use disorder
• Cognitive orthotics
• Depersonalization-derealization disorder
• Excessive daytime sleepiness
• Four boxes test
• Idiopathic hypersomnia
• Insomnia
• Mental confusion
• Mild cognitive impairment
• Obtundation
• Postural orthostatic tachycardia syndrome (POTS)
• Post-chemotherapy cognitive impairment
• Pumphead syndrome
• Reactive hypoglycemia
• Sleep inertia
• Slow-wave sleep
• Somnolence
• Stupor

{{div col end}}

{{reflist}}

Category:Symptoms and signs of mental disorders

Category:Symptoms and signs: Nervous system

Category:Cognitive disorders

Category:Psychopathological syndromes

Category:Symptoms, signs or clinical findings involving consciousness

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sr:Когнитивна дисфункција