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{{distinguish-otheruses|Psychopathy|Psychosis (disambiguation)}}

MAIOLAST2=FRANSCELL NAME-LIST-FORMAT = VANC DATE=2016ISBN=978-1-4668-7506-7URL=HTTPS://BOOKS.GOOGLE.CO.JP/BOOKS?ID=E7HPCGAAQBAJ&PG=PA236, BOGOUSSLAVSKY>FIRST1=JULIENFIRST2=FRANçOISTITLE=NEUROLOGICAL DISORDERS IN FAMOUS ARTISTSPUBLISHER=KARGER MEDICAL AND SCIENTIFIC PUBLISHERSPAGE=125LANGUAGE=EN, | field = Psychiatry, psychologydelusions>False beliefs, seeing or hearing things that others do not see or hear, incoherent speech| complications = Self-harm, suicide| onset = | duration = | types = | causes = Mental illness (schizophrenia, bipolar disorder), sleep deprivation, some medical conditions, certain medications, drugs (including alcohol and cannabis)| risks = | diagnosis = | differential = | prevention = | treatment = Antipsychotics, counselling, social support| medication =| prognosis = Depends on cause| frequency = 3% of people at some point in time (US)| deaths = }}Psychosis is an abnormal condition of the mind that results in difficulties determining what is real and what is not.WEB, RAISE Questions and Answers,weblink NIMH, 23 January 2018, en, Symptoms may include false beliefs (delusions) and seeing or hearing things that others do not see or hear (hallucinations). Other symptoms may include incoherent speech and behavior that is inappropriate for the situation. There may also be sleep problems, social withdrawal, lack of motivation, and difficulties carrying out daily activities.Psychosis has many different causes. These include mental illness, such as schizophrenia or bipolar disorder, sleep deprivation, some medical conditions, certain medications, and drugs such as alcohol or cannabis. One type, known as postpartum psychosis, can occur after giving birth.WEB, Psychosis Symptoms,weblink NHS, 24 January 2018, The neurotransmitter dopamine is believed to play a role.WEB, Psychosis Causes,weblink NHS, 24 January 2018, Acute psychosis is considered primary if it results from a psychiatric condition and secondary if it is caused by a medical condition.JOURNAL, Griswold KS, Del Regno PA, Berger RC, Recognition and Differential Diagnosis of Psychosis in Primary Care, American Family Physician, 91, 12, 856–63, June 2015, 26131945, The diagnosis of a mental illness requires excluding other potential causes.BOOK, Cardinal, Rudolf N., Bullmore, Edward T., vanc, The Diagnosis of Psychosis, 2011, Cambridge University Press, 978-1-139-49790-9, 279,weblink en, Testing may be done to check for central nervous system diseases, toxins, or other health problems as a cause.BOOK, Foster, Norman L., The American Psychiatric Publishing Textbook of Geriatric Neuropsychiatry, 2011, American Psychiatric Pub, 978-1-58562-952-7, 523,weblink en, Treatment may include antipsychotic medication, counselling, and social support. Early treatment appears to improve outcomes. Medications appear to have a moderate effect.JOURNAL, Leucht S, Arbter D, Engel RR, Kissling W, Davis JM, How effective are second-generation antipsychotic drugs? A meta-analysis of placebo-controlled trials, Molecular Psychiatry, 14, 4, 429–47, April 2009, 18180760, 10.1038/,weblink JOURNAL, Rattehalli RD, Jayaram MB, Smith M, Risperidone versus placebo for schizophrenia, Schizophrenia Bulletin, 36, 3, 448–9, May 2010, 20368309, 2879694, 10.1093/schbul/sbq030, Outcomes depend on the underlying cause.WEB, Psychosis,weblink NHS, 24 January 2018, 23 December 2016, In the United States about 3% of people develop psychosis at some point in their lives. The condition has been described since at least the 4th century BCE by Hippocrates and possibly as early as 1,500 BCE in the Egyptian Ebers Papyrus.BOOK, Gibbs, Ronald S., Danforth's Obstetrics and Gynecology, 2008, Lippincott Williams & Wilkins, 978-0-7817-6937-2, 508,weblink BOOK, Giddens, Jean Foret, Concepts for Nursing Practice - E-Book, 2015, Elsevier Health Sciences, 978-0-323-38946-4, 348,weblink {{TOC limit|3}}

Signs and symptoms


A hallucination is defined as sensory perception in the absence of external stimuli. Hallucinations are different from illusions and perceptual distortions, which are the misperception of external stimuli. Hallucinations may occur in any of the senses and take on almost any form. They may consist of simple sensations (such as lights, colors, sounds, tastes, or smells) or more detailed experiences (such as seeing and interacting with animals and people, hearing voices, and having complex tactile sensations). Hallucinations are generally characterized as being vivid and uncontrollable.Auditory hallucinations, particularly experiences of hearing voices, are the most common and often prominent feature of psychosis.
Up to 15% of the general population may experience auditory hallucinations. The prevalence in schizophrenia is generally put around 70%, but may go as high as 98%. During the early 20th century, auditory hallucinations were second to visual hallucinations in frequency, but they are now the most common manifestation of schizophrenia, although rates vary between cultures and regions. Auditory hallucinations are most commonly intelligible voices. When voices are present, the average number has been estimated at three. Content, like frequency, differs significantly, especially across cultures and demographics. People who experience auditory hallucinations can frequently identify the loudness, location of origin, and may settle on identities for voices. Western cultures are associated with auditory experiences concerning religious content, frequently related to sin. Hallucinations may command a person to do something potentially dangerous when combined with delusions.BOOK, Lewis, Stephen, Escalona, Rodrigo, Keith, Samuel, Sadock, Virginia, Sadock, Benjamin, Ruiz, Pedro, vanc, Kaplan and Sadock's Comprehensive Textbook of Psychiatry, Wolters Kluwer, Phenomenology of Schizophrenia, Extracampine hallucinations are auditory hallucinations originating from a particular body part (e.g., a voice coming from a person's knee).Visual hallucinations occur in roughly a third of people with schizophrenia, although rates as high as 55% are reported. Content frequently involves animate objects, although perceptual abnormalities such as changes in lighting, shading, streaks, or lines may be seen. Visual abnormalities may conflict with proprioceptive information, and visions may include experiences such as the ground tilting. Lilliputian hallucinations are less common in schizophrenia, and occur more frequently in various types of encephalopathy (e.g., Peduncular hallucinosis).A visceral hallucination, also called a cenesthetic hallucination, is characterized by visceral sensations in the absence of stimuli. Cenesthetic hallucinations may include sensations of burning, or re-arrangement of internal organs.


Psychosis may involve delusional beliefs. Delusions are strong beliefs against reality or held despite contradictory evidence. Delusions are necessarily incongruent with societal norms, as some beliefs may constitute a delusion in certain cultures where they impact functioning, while they may be a perfectly normal belief in others. The distinguishing feature between delusional thinking and full-blown delusions is the degree with which they impact functioning. Multiple themes are common in delusions, although cultural norms are highly influential (e.g. religious content differing significantly across countries). The most common type of delusion is a persecutory delusion, where a person believes that an individual, organization or group is attempting to harm them. Other delusions include delusions of reference (beliefs that a particular stimulus has a special meaning that is directed at the holder of belief), grandiose delusions (delusions that a person has a special power or importance), thought broadcasting (the belief that one's thoughts are audible) and thought insertion (the belief that one's thoughts are not one's own). The DSM-5 characterizes certain delusions as "bizarre" if they are clearly implausible, or are incompatible within the cultural context. The concept of bizarre delusions has been criticized as excessively subjective.Historically, Karl Jaspers has classified psychotic delusions into primary and secondary types. Primary delusions are defined as arising suddenly and not being comprehensible in terms of normal mental processes, whereas secondary delusions are typically understood as being influenced by the person's background or current situation (e.g., ethnicity; also religious, superstitious, or political beliefs).BOOK, Jaspers, Karl, vanc, Karl Jaspers, Translated by J. Hoenig and M.W. Hamilton from German, Allgemeine Psychopathologie (General Psychopathology), 1963, Reprint, 1997-11-27, Johns Hopkins University Press, Baltimore, Maryland, 978-0-8018-5775-1,


Disorganization is split into disorganized speech or thinking, and grossly disorganized motor behavior. Disorganized speech, also called formal thought disorder, is disorganization of thinking that is inferred from speech. Characteristics of disorganized speech include rapidly switching topics, called derailment or loose association; switching to topics that are unrelated, called tangential thinking; incomprehensible speech, called word salad or incoherence. Disorganized motor behavior includes repetitive, odd, or sometimes purposeless movement. Disorganized motor behavior rarely includes catatonia, and although it was a historically prominent symptom, it is rarely seen today. Whether this is due to historically used treatments or the lack thereof is unknown.Catatonia describes a profoundly agitated state in which the experience of reality is generally considered impaired. There are two primary manifestations of catatonic behavior. The classic presentation is a person who does not move or interact with the world in any way while awake. This type of catatonia presents with waxy flexibility. Waxy flexibility is when someone physically moves part of a catatonic person's body and the person stays in the position even if it is bizarre and otherwise nonfunctional (such as moving a person's arm straight up in the air and the arm staying there).The other type of catatonia is more of an outward presentation of the profoundly agitated state described above. It involves excessive and purposeless motor behaviour, as well as extreme mental preoccupation that prevents an intact experience of reality. An example is someone walking very fast in circles to the exclusion of anything else with a level of mental preoccupation (meaning not focused on anything relevant to the situation) that was not typical of the person prior to the symptom onset. In both types of catatonia there is generally no reaction to anything that happens outside of them. It is important to distinguish catatonic agitation from severe bipolar mania, although someone could have both.

Negative symptoms

Negative symptoms include reduced emotional expression, decreased motivation, and reduced spontaneous speech. They lack interest and spontaneity, and have the inability to feel pleasure.WEB,weblink What is Psychosis? Symptoms of Psychosis, 2018,,


Normal states

Brief hallucinations are not uncommon in those without any psychiatric disease. Causes or triggers include:
  • Falling asleep and waking: hypnagogic and hypnopompic hallucinations, which are entirely normalJOURNAL, Ohayon MM, Priest RG, Caulet M, Guilleminault C, Hypnagogic and hypnopompic hallucinations: pathological phenomena?, The British Journal of Psychiatry, 169, 4, 459–67, October 1996, 8894197, 10.1192/bjp.169.4.459,
  • Bereavement, in which hallucinations of a deceased loved one are common
  • Severe sleep deprivationJOURNAL, Sharma V, Mazmanian D, Sleep loss and postpartum psychosis, Bipolar Disorders, 5, 2, 98–105, April 2003, 12680898, 10.1034/j.1399-5618.2003.00015.x, JOURNAL, Chan-Ob T, Boonyanaruthee V, Meditation in association with psychosis, Journal of the Medical Association of Thailand = Chotmaihet Thangphaet, 82, 9, 925–30, September 1999, 10561951, JOURNAL, Devillieres P, Opitz M, Clervoy P, Stephany J, May–June 1996, Delusion and sleep deprivation, L'Encéphale, 22, 3, 229–31, 8767052,


Traumatic life events have been linked with elevated risk in developing psychotic symptoms.JOURNAL, Gibson LE, Alloy LB, Ellman LM, Trauma and the psychosis spectrum: A review of symptom specificity and explanatory mechanisms, Clinical Psychology Review, 49, 92–105, November 2016, 27632064, 5157832, 10.1016/j.cpr.2016.08.003, Childhood trauma has specifically been shown to be a predictor of adolescent and adult psychosis.JOURNAL, Misiak B, Krefft M, Bielawski T, Moustafa AA, Sąsiadek MM, Frydecka D, Toward a unified theory of childhood trauma and psychosis: A comprehensive review of epidemiological, clinical, neuropsychological and biological findings, Neuroscience and Biobehavioral Reviews, 75, 393–406, April 2017, 28216171, 10.1016/j.neubiorev.2017.02.015, Approximately 65% of individuals with psychotic symptoms have experienced childhood trauma (e.g., physical or sexual abuse, physical or emotional neglect).JOURNAL, Read J, van Os J, Morrison AP, Ross CA, Childhood trauma, psychosis and schizophrenia: a literature review with theoretical and clinical implications, Acta Psychiatrica Scandinavica, 112, 5, 330–50, November 2005, 16223421, 10.1111/j.1600-0447.2005.00634.x, Increased individual vulnerability toward psychosis may interact with traumatic experiences promoting onset of future psychotic symptoms, particularly during sensitive developmental periods. Importantly, the relationship between traumatic life events and psychotic symptoms appears to be dose-dependent in which multiple traumatic life events accumulate, compounding symptom expression and severity. This suggests trauma prevention and early intervention may be an important target for decreasing the incidence of psychotic disorders and ameliorating its effects.

Psychiatric disorder

From a diagnostic standpoint, organic disorders were believed to be caused by physical illness affecting the brain (that is, psychiatric disorders secondary to other conditions) while functional disorders were considered disorders of the functioning of the mind in the absence of physical disorders (that is, primary psychological or psychiatric disorders). Subtle physical abnormalities have been found in illnesses traditionally considered functional, such as schizophrenia. The DSM-IV-TR avoids the functional/organic distinction, and instead lists traditional psychotic illnesses, psychosis due to general medical conditions, and substance-induced psychosis.Primary psychiatric causes of psychosis include the following:World Health Organization, The ICD-10 Classification of Mental and Behavioural Disorders: Clinical descriptions and diagnostic guidelines (CDDG), 1992.American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR), American Psychiatric Association, 2000.BOOK, Cardinal RN, Bullmore, ET, Edward Bullmore, The Diagnosis of Psychosis, Cambridge University Press, 2011, 978-0-521-16484-9, Psychotic symptoms may also be seen in: Stress is known to contribute to and trigger psychotic states. A history of psychologically traumatic events, and the recent experience of a stressful event, can both contribute to the development of psychosis. Short-lived psychosis triggered by stress is known as brief reactive psychosis, and patients may spontaneously recover normal functioning within two weeks.JOURNAL, Jauch DA, Carpenter WT, Reactive psychosis. I. Does the pre-DSM-III concept define a third psychosis?, The Journal of Nervous and Mental Disease, 176, 2, 72–81, February 1988, 3276813, 10.1097/00005053-198802000-00002, In some rare cases, individuals may remain in a state of full-blown psychosis for many years, or perhaps have attenuated psychotic symptoms (such as low intensity hallucinations) present at most times.Neuroticism is an independent predictor of the development of psychosis.JOURNAL, Jeronimus BF, Kotov R, Riese H, Ormel J, Neuroticism's prospective association with mental disorders halves after adjustment for baseline symptoms and psychiatric history, but the adjusted association hardly decays with time: a meta-analysis on 59 longitudinal/prospective studies with 443 313 participants, Psychological Medicine, 46, 14, 2883–2906, October 2016, 27523506, 10.1017/S0033291716001653,


Subtypes of psychosis include:

Cycloid psychosis

Cycloid psychosis is a psychosis that progresses from normal to full-blown, usually between a few hours to days, not related to drug intake or brain injury.BOOK, Frank, Pillmann, Andreas, Marneros, vanc, Acute and transient psychoses, Cambridge University Press, Cambridge, UK, 2004,weblink 188, 978-0-521-83518-3, 144618418, The cycloid psychosis has a long history in European psychiatry diagnosis. The term "cycloid psychosis" was first used by Karl Kleist in 1926. Despite the significant clinical relevance, this diagnosis is neglected both in literature as in nosology. The cycloid psychosis has attracted much interest in the international literature of the past 50 years, but the number of scientific studies have greatly decreased over the past 15 years, possibly partly explained by the misconception that the diagnosis has been incorporated in current diagnostic classification systems. The cycloid psychosis is therefore only partially described in the diagnostic classification systems used. Cycloid psychosis is nevertheless its own specific disease that is distinct from both the manic-depressive disorder, and from schizophrenia, and this despite the fact that the cycloid psychosis can include both bipolar (basic mood shifts) as well as schizophrenic symptoms. The disease is an acute, usually self-limiting, functionally psychotic state, with a very diverse clinical picture that almost consistently is characterized by the existence of some degree of confusion or distressing perplexity, but above all, of the multifaceted and diverse expressions the disease takes. The main features of the disease is thus that the onset is acute, the multifaceted picture of symptoms and typically reverses to a normal state and that the long-term prognosis is good. In addition, diagnostic criteria include at least four of the following symptoms:
  • Confusion
  • Mood-incongruent delusions
  • Hallucinations
  • Pan-anxiety, a severe anxiety not bound to particular situations or circumstances
  • Happiness or ecstasy of high degree
  • Motility disturbances of akinetic or hyperkinetic type
  • Concern with death
  • Mood swings to some degree, but less than what is needed for diagnosis of an affective disorder
Cycloid psychosis occurs in people of generally 15–50 years of age.

Medical conditions

A very large number of medical conditions can cause psychosis, sometimes called secondary psychosis. Examples include:
  • disorders causing delirium (toxic psychosis), in which consciousness is disturbed
  • neurodevelopmental disorders and chromosomal abnormalities, including velocardiofacial syndrome
  • neurodegenerative disorders, such as Alzheimer's disease,JOURNAL, Lesser JM, Hughes S, Psychosis-related disturbances. Psychosis, agitation, and disinhibition in Alzheimer's disease: definitions and treatment options, Geriatrics, 61, 12, 14–20, December 2006, 17184138, dementia with Lewy bodies,JOURNAL, McKeith IG, Dementia with Lewy bodies, The British Journal of Psychiatry, 180, 2, 144–7, February 2002, 11823325, 10.1192/bjp.180.2.144, and Parkinson's diseaseJOURNAL, Wedekind S, [Depressive syndrome, psychoses, dementia: frequent manifestations in Parkinson disease], German, MMW Fortschritte der Medizin, 147, 22, 11, June 2005, 15977623, JOURNAL, Arciniegas DB, Psychosis, Continuum, 21, 3 Behavioral Neurology and Neuropsychiatry, 715–36, June 2015, 26039850, 4455840, 10.1212/01.CON.0000466662.89908.e7,
  • focal neurological disease, such as stroke, brain tumors,JOURNAL, Lisanby SH, Kohler C, Swanson CL, Gur RE, Psychosis Secondary to Brain Tumor, Seminars in Clinical Neuropsychiatry, 3, 1, 12–22, January 1998, 10085187, multiple sclerosis, and some forms of epilepsy
  • malignancy (typically via masses in the brain, paraneoplastic syndromes)
  • infectious and postinfectious syndromes, including infections causing delirium, viral encephalitis, HIV/AIDS,BOOK, Evans, Dwight L., Karen I., Mason, Jane, Leserman, Russell, Bauer, John, Petitto, vanc, Davis KL, Charney D, Coyle JT, Nemeroff C, Neuropsychopharmacology: The Fifth Generation of Progress,weblink 2006-10-16, 5th, 2002-02-01, Lippincott Williams & Wilkins, Philadelphia, 978-0-7817-2837-9, 1281–1301, Chapter 90: Neuropsychiatric Manifestations of HIV-1 Infection and AIDS,weblink yes,weblink" title="">weblink 2006-10-19, malaria,JOURNAL, Nevin RL, Croft AM, Psychiatric effects of malaria and anti-malarial drugs: historical and modern perspectives, Malaria Journal, 15, 332, June 2016, 27335053, 4918116, 10.1186/s12936-016-1391-6, syphilisJOURNAL, Friedrich F, Aigner M, Fearns N, Friedrich ME, Frey R, Geusau A, Psychosis in neurosyphilis -- clinical aspects and implications, Psychopathology, 47, 1, 3–9, 2014, 23711816, 10.1159/000350059,
  • endocrine disease, such as hypothyroidism, hyperthyroidism, Cushing's syndrome, hypoparathyroidism and hyperparathyroidism;JOURNAL, Keshavan MS, Kaneko Y, Secondary psychoses: an update, World Psychiatry, 12, 1, 4–15, February 2013, 23471787, 3619167, 10.1002/wps.20001, sex hormones also affect psychotic symptoms and sometimes giving birth can provoke psychosis, termed postpartum psychosisJOURNAL, Sit D, Rothschild AJ, Wisner KL, A review of postpartum psychosis, Journal of Women's Health, 15, 4, 352–68, May 2006, 16724884, 3109493, 10.1089/jwh.2006.15.352,
  • inborn errors of metabolism, such as Succinic semialdehyde dehydrogenase deficiency, porphyria and metachromatic leukodystrophyJOURNAL, Foucher JR, Luck D, Psychosis related to neurological conditions: pro and cons of the dis- / mis-connectivity models of schizophrenia, Dialogues in Clinical Neuroscience, 8, 1, 17–27, 2006, 16640110, 3181754, JOURNAL, Bonnot O, Klünemann HH, Sedel F, Tordjman S, Cohen D, Walterfang M, Diagnostic and treatment implications of psychosis secondary to treatable metabolic disorders in adults: a systematic review, Orphanet Journal of Rare Diseases, 9, 65, April 2014, 24775716, 4043981, 10.1186/1750-1172-9-65, JOURNAL, Sedel F, Baumann N, Turpin JC, Lyon-Caen O, Saudubray JM, Cohen D, Psychiatric manifestations revealing inborn errors of metabolism in adolescents and adults, Journal of Inherited Metabolic Disease, 30, 5, 631–41, October 2007, 17694356, 10.1007/s10545-007-0661-4, JOURNAL, Bonnot O, Herrera PM, Tordjman S, Walterfang M, Secondary psychosis induced by metabolic disorders, Frontiers in Neuroscience, 9, 177, 2015, 26074754, 4436816, 10.3389/fnins.2015.00177,
  • nutritional deficiency, such as vitamin B12 deficiency
  • other acquired metabolic disorders, including electrolyte disturbances such as hypocalcemia, hypernatremia,JOURNAL, Jana DK, Romano-Jana L, Hypernatremic psychosis in the elderly: case reports, Journal of the American Geriatrics Society, 21, 10, 473–7, October 1973, 4729012, 10.1111/j.1532-5415.1973.tb01212.x, hyponatremia,JOURNAL, Haensch CA, Hennen G, Jörg J, [Reversible exogenous psychosis in thiazide-induced hyponatremia of 97 mmol/l], Der Nervenarzt, 67, 4, 319–22, April 1996, 8684511, hypokalemia,JOURNAL, Hafez H, Strauss JS, Aronson MD, Holt C, Hypokalemia-induced psychosis in a chronic schizophrenic patient, The Journal of Clinical Psychiatry, 45, 6, 277–9, June 1984, 6725222, hypomagnesemia,WEB,weblink Hypomagnesemia, October 16, 2006, Konstantakos AK, Grisoni E, May 25, 2006, eMedicine, WebMD, hypermagnesemia,JOURNAL, Velasco PJ, Manshadi M, Breen K, Lippmann S, Psychiatric aspects of parathyroid disease, Psychosomatics, 40, 6, 486–90, 1 December 1999, 10581976, 10.1016/S0033-3182(99)71186-2, hypercalcemia,JOURNAL, Rosenthal M, Gil I, Habot B, Primary hyperparathyroidism: neuropsychiatric manifestations and case report, The Israel Journal of Psychiatry and Related Sciences, 34, 2, 122–5, 1997, 9231574, and hypophosphatemia,JOURNAL, Nanji AA, The psychiatric aspect of hypophosphatemia, Canadian Journal of Psychiatry, 29, 7, 599–600, November 1984, 6391648, 10.1177/070674378402900710, but also hypoglycemia,JOURNAL, Padder, Tanveer, Aparna, Udyawar, Nouman, Azhar, Kamil, Jaghab, vanc, December 2005, Acute Hypoglycemia Presenting as Acute Psychosis, Psychiatry Online,weblink 2006-09-27, hypoxia, and failure of the liver or kidneys
  • autoimmune and related disorders, such as systemic lupus erythematosus (lupus, SLE), sarcoidosis, Hashimoto's encephalopathy, anti-NMDA-receptor encephalitis, and non-celiac gluten sensitivityJOURNAL, Losurdo G, Principi M, Iannone A, Amoruso A, Ierardi E, Di Leo A, Barone M, Extra-intestinal manifestations of non-celiac gluten sensitivity: An expanding paradigm, World Journal of Gastroenterology, 24, 14, 1521–1530, April 2018, 29662290, 5897856, 10.3748/wjg.v24.i14.1521, Review,
  • poisoning, by therapeutic drugs (see below), recreational drugs (see below), and a range of plants, fungi, metals, organic compounds, and a few animal toxins
  • sleep disorders, such as in narcolepsy (in which REM sleep intrudes into wakefulness)
  • parasitic diseases, such as neurocysticercosis

Psychoactive drugs

Various psychoactive substances (both legal and illegal) have been implicated in causing, exacerbating, or precipitating psychotic states or disorders in users, with varying levels of evidence. This may be upon intoxication for a more prolonged period after use, or upon withdrawal. Individuals who have a substance induced psychosis tend to have a greater awareness of their psychosis and tend to have higher levels of suicidal thinking compared to individuals who have a primary psychotic illness.JOURNAL, Grant KM, LeVan TD, Wells SM, Li M, Stoltenberg SF, Gendelman HE, Carlo G, Bevins RA, Methamphetamine-associated psychosis, Journal of Neuroimmune Pharmacology, 7, 1, 113–39, March 2012, 21728034, 3280383, 10.1007/s11481-011-9288-1, Drugs commonly alleged to induce psychotic symptoms include alcohol, cannabis, cocaine, amphetamines, cathinones, psychedelic drugs (such as LSD and psilocybin), κ-opioid receptor agonists (such as enadoline and salvinorin A) and NMDA receptor antagonists (such as phencyclidine and ketamine).JOURNAL, Krebs TS, Johansen PØ, Psychedelics and mental health: a population study, PLOS One, 8, 8, e63972, August 2013, 23976938, 3747247, 10.1371/journal.pone.0063972, Caffeine may worsen symptoms in those with schizophrenia and cause psychosis at very high doses in people without the condition.JOURNAL, Broderick P, Benjamin AB, Caffeine and psychiatric symptoms: a review, The Journal of the Oklahoma State Medical Association, 97, 12, 538–42, December 2004, 15732884, BOOK, Cardinal, Rudolf N., Bullmore, Edward T., vanc, The Diagnosis of Psychosis, 2011, Cambridge University Press, 978-1-139-49790-9, 126,weblink


{{further|Long-term effects of alcohol#Mental health effects}}Approximately three percent of people who are suffering from alcoholism experience psychosis during acute intoxication or withdrawal. Alcohol related psychosis may manifest itself through a kindling mechanism. The mechanism of alcohol-related psychosis is due to the long-term effects of alcohol resulting in distortions to neuronal membranes, gene expression, as well as thiamin deficiency. It is possible in some cases that alcohol abuse via a kindling mechanism can cause the development of a chronic substance induced psychotic disorder, i.e. schizophrenia. The effects of an alcohol-related psychosis include an increased risk of depression and suicide as well as causing psychosocial impairments.{{EMedicine|med|3113|Alcohol-Related Psychosis}}


{{further|Causes of schizophrenia#Cannabis|Long-term effects of cannabis#Schizophrenia}}According to some studies, the more often cannabis is used the more likely a person is to develop a psychotic illness,JOURNAL, Moore TH, Zammit S, Lingford-Hughes A, Barnes TR, Jones PB, Burke M, Lewis G, Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review, Lancet, 370, 9584, 319–28, July 2007, 17662880, 10.1016/S0140-6736(07)61162-3,weblink with frequent use being correlated with twice the risk of psychosis and schizophrenia.JOURNAL, Leweke FM, Koethe D, Cannabis and psychiatric disorders: it is not only addiction, Addiction Biology, 13, 2, 264–75, June 2008, 18482435, 10.1111/j.1369-1600.2008.00106.x, JOURNAL, Sewell RA, Ranganathan M, D'Souza DC, Cannabinoids and psychosis, International Review of Psychiatry, 21, 2, 152–62, April 2009, 19367509, 10.1080/09540260902782802, While cannabis use is accepted as a contributory cause of schizophrenia by some,JOURNAL, Henquet C, Di Forti M, Morrison P, Kuepper R, Murray RM, Gene-environment interplay between cannabis and psychosis, Schizophrenia Bulletin, 34, 6, 1111–21, November 2008, 18723841, 2632498, 10.1093/schbul/sbn108, it remains controversial, with pre-existing vulnerability to psychosis emerging as the key factor that influences the link between cannabis use and psychosis.JOURNAL, McLaren JA, Silins E, Hutchinson D, Mattick RP, Hall W, Assessing evidence for a causal link between cannabis and psychosis: a review of cohort studies, The International Journal on Drug Policy, 21, 1, 10–9, January 2010, 19783132, 10.1016/j.drugpo.2009.09.001, JOURNAL, Ben Amar M, Potvin S, Cannabis and psychosis: what is the link?, Journal of Psychoactive Drugs, 39, 2, 131–42, June 2007, 17703707, 10.1080/02791072.2007.10399871, Some studies indicate that the effects of two active compounds in cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD), have opposite effects with respect to psychosis. While THC can induce psychotic symptoms in healthy individuals, CBD may reduce the symptoms caused by cannabis.JOURNAL, Bhattacharyya S, Morrison PD, Fusar-Poli P, Martin-Santos R, Borgwardt S, Winton-Brown T, Nosarti C, O' Carroll CM, Seal M, Allen P, Mehta MA, Stone JM, Tunstall N, Giampietro V, Kapur S, Murray RM, Zuardi AW, Crippa JA, Atakan Z, McGuire PK, Opposite effects of delta-9-tetrahydrocannabinol and cannabidiol on human brain function and psychopathology, Neuropsychopharmacology, 35, 3, 764–74, February 2010, 19924114, 3055598, 10.1038/npp.2009.184, Cannabis use has increased dramatically over the past few decades whereas the rate of psychosis has not increased. Together, these findings suggest that cannabis use may hasten the onset of psychosis in those who may already be predisposed to psychosis.JOURNAL, Degenhardt L, Hall W, Lynskey M, Comorbidity between cannabis use and psychosis: Modelling some possible relationships, Technical Report No. 121., Sydney: National Drug and Alcohol Research Centre., 2001,weblink PDF, 2006-08-19, High-potency cannabis use indeed seems to accelerate the onset of psychosis in predisposed patients.JOURNAL, Di Forti M, Sallis H, Allegri F, Trotta A, Ferraro L, Stilo SA, Marconi A, La Cascia C, Reis Marques T, Pariante C, Dazzan P, Mondelli V, Paparelli A, Kolliakou A, Prata D, Gaughran F, David AS, Morgan C, Stahl D, Khondoker M, MacCabe JH, Murray RM, 6, Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users, Schizophrenia Bulletin, 40, 6, 1509–17, November 2014, 24345517, 4193693, 10.1093/schbul/sbt181, A 2012 study concluded that cannabis plays an important role in the development of psychosis in vulnerable individuals, and that cannabis use in early adolescence should be discouraged.JOURNAL, Dragt S, Nieman DH, Schultze-Lutter F, van der Meer F, Becker H, de Haan L, Dingemans PM, Birchwood M, Patterson P, Salokangas RK, Heinimaa M, Heinz A, Juckel G, Graf von Reventlow H, French P, Stevens H, Ruhrmann S, Klosterkötter J, Linszen DH, 6, Cannabis use and age at onset of symptoms in subjects at clinical high risk for psychosis, Acta Psychiatrica Scandinavica, 125, 1, 45–53, January 2012, 21883099, 10.1111/j.1600-0447.2011.01763.x,


Methamphetamine induces a psychosis in 26–46 percent of heavy users. Some of these people develop a long-lasting psychosis that can persist for longer than six months. Those who have had a short-lived psychosis from methamphetamine can have a relapse of the methamphetamine psychosis years later after a stress event such as severe insomnia or a period of heavy alcohol abuse despite not relapsing back to methamphetamine.{{Citation needed|date=June 2014}} Individuals who have long history of methamphetamine abuse and who have experienced psychosis in the past from methamphetamine abuse are highly likely to rapidly relapse back into a methamphetamine psychosis within a week or so of going back onto methamphetamine.{{Citation needed|date=July 2015}}


Administration, or sometimes withdrawal, of a large number of medications may provoke psychotic symptoms. Drugs that can induce psychosis experimentally or in a significant proportion of people include amphetamine and other sympathomimetics, dopamine agonists, ketamine, corticosteroids (often with mood changes in addition), and some anticonvulsants such as vigabatrin.JOURNAL, Sander JW, Hart YM, Trimble MR, Shorvon SD, Vigabatrin and psychosis, Journal of Neurology, Neurosurgery, and Psychiatry, 54, 5, 435–9, May 1991, 1865207, 488544, 10.1136/jnnp.54.5.435, Stimulants that may cause this include lisdexamfetamine.WEB, Adderall XR Prescribing Information,weblink 4–6, United States Food and Drug Administration, December 2013, 30 December 2013, Meditation may induce psychological side effects, including depersonalization, derealization and psychotic symptoms like hallucinations as well as mood disturbances.JOURNAL, Kuijpers HJ, van der Heijden FM, Tuinier S, Verhoeven WM, Meditation-induced psychosis, Psychopathology, 40, 6, 461–4, 2007, 17848828, 10.1159/000108125,



The first brain image of an individual with psychosis was completed as far back as 1935 using a technique called pneumoencephalographyJOURNAL, Moore MT, Nathan D, Elliott AR, Laubach C, Encephalographic studies in mental disease, American Journal of Psychiatry, 92, 1, 43–67, 10.1176/ajp.92.1.43, 1935, (a painful and now obsolete procedure where cerebrospinal fluid is drained from around the brain and replaced with air to allow the structure of the brain to show up more clearly on an X-ray picture).Both first episode psychosis, and high risk status is associated with reductions in grey matter volume. First episode psychotic and high risk populations are associated with similar but distinct abnormalities in GMV. Reductions in the right middle temporal gyrus, right superior temporal gyrus, right parahippocampus, right hippocampus, right middle frontal gyrus, and left anterior cingulate cortex are observed in high risk populations. Reductions in first episode psychosis span a region from the right STG to the right insula, left insula, and cerebellum, and are more severe in the right ACC, right STG, insula and cerebellum.JOURNAL, Fusar-Poli P, Radua J, McGuire P, Borgwardt S, Neuroanatomical maps of psychosis onset: voxel-wise meta-analysis of antipsychotic-naive VBM studies, Schizophrenia Bulletin, 38, 6, 1297–307, November 2012, 22080494, 3494061, 10.1093/schbul/sbr134, JOURNAL, Palaniyappan L, Balain V, Liddle PF, The neuroanatomy of psychotic diathesis: a meta-analytic review, Journal of Psychiatric Research, 46, 10, 1249–56, October 2012, 22790253, 10.1016/j.jpsychires.2012.06.007, Another meta analysis reported similar reductions in temporal, medial frontal, and insular regions, but also reported increased GMV in the right lingual gyrus and left precentral gyrus.JOURNAL, Radua J, Borgwardt S, Crescini A, Mataix-Cols D, Meyer-Lindenberg A, McGuire PK, Fusar-Poli P, Multimodal meta-analysis of structural and functional brain changes in first episode psychosis and the effects of antipsychotic medication, Neuroscience and Biobehavioral Reviews, 36, 10, 2325–33, November 2012, 22910680, 10.1016/j.neubiorev.2012.07.012, The Kraeplinian dichotomy is made questionable by grey matter abnormalities in bipolar and schizophrenia; schizophrenia is distinguishable from bipolar in that regions of grey matter reduction are generally larger in magnitude, although adjusting for gender differences reduces the difference to the left dorsomedial prefrontal cortex, and right dorsolateral prefrontal cortex.JOURNAL, Bora E, Fornito A, Yücel M, Pantelis C, The effects of gender on grey matter abnormalities in major psychoses: a comparative voxelwise meta-analysis of schizophrenia and bipolar disorder, Psychological Medicine, 42, 2, 295–307, February 2012, 21835091, 10.1017/S0033291711001450, During attentional tasks, first episode psychosis is associated with hypoactivation in the right middle frontal gyrus, a region generally described as encompassing the dorsolateral prefrontal cortex (dlPFC). In congruence with studies on grey matter volume, hypoactivity in the right insula, and right inferior parietal lobe is also reported.JOURNAL, Del Casale A, Kotzalidis GD, Rapinesi C, Sorice S, Girardi N, Ferracuti S, Girardi P, Functional Magnetic Resonance Imaging Correlates of First-Episode Psychoses during Attentional and Memory Task Performance, Neuropsychobiology, 74, 1, 22–31, 2016, 27698323, 10.1159/000448620, With the exceptions of reduced deactivation of the inferior frontal gyrus during cognitive tasks(i.e. hyperactivation), highly consistent and replicable hypoactivity in the right insula, dACC, and precuneus, as well as hyperactivity in the right basal ganglia and thalamus is observed. Decreased grey matter volume in conjunction with hypoactivity is observed in the dorsal ACC, right anterior/middle insula, and left middle insula. Decreased grey matter volume and hyperactivity is reported in the ventral ACC(i.e. the pgACC and sgACC), and more posterior regions of the insula.


Studies during acute experience of hallucinations demonstrate increased activity in primary or secondary sensory cortices. As auditory hallucinations are most common in psychosis, most robust evidence exists for increased activity in the left middle temporal gyrus, left superior temporal gyrus, and left inferior frontal gyrus (i.e. Broca's area). Activity in the ventral striatum, hippocampus, and ACC are related to the lucidity of hallucinations, and indicate that activation or involvement of emotional circuitry are key to the impact of abnormal activity in sensory cortices. Together, these findings indicate abnormal processing of internally generated sensory experiences, coupled with abnormal emotional processing, results in hallucinations. One proposed model involves a failure of feedforward networks from sensory cortices to the inferior frontal cortex, which normally cancel out sensory cortex activity during internally generated speech. The resulting disruption in expected and perceived speech is thought to produce lucid hallucinatory experiences.BOOK, Brown, Gregory, Thompson, Wesley, Swerdlow, Neal, vanc, Behavioral Neurobiology of Schizophrenia and its Treatment, Springer, 185–189, Functional Brain Imaging in Schizophrenia: Selected Results and Methods,


The two factor model of delusions posits that dysfunction in both belief formation systems and belief evaluation systems are necessary for delusions. Dysfunction in evaluations systems localized to the right lateral prefrontal cortex, regardless of delusion content, is supported by neuroimaging studies and is congruent with its role in conflict monitoring in healthy persons. Abnormal activation and reduced volume is seen in people with delusions, as well as in disorders associated with delusions such as frontotemporal dementia, psychosis and Lewy body dementia. Furthermore, lesions to this region are associated with "jumping to conclusions", damage to this region is associated with post-stroke delusions, and hypometabolism this region associated with caudate strokes presenting with delusions.The aberrant salience model suggests that delusions are a result of people assigning excessive importance to irrelevant stimuli. In support of this hypothesis, regions normally associated with the salience network demonstrate reduced grey matter in people with delusions, and the neurotransmitter dopamine, which is widely implicated in salience processing, is also widely implicated in psychotic disorders.Specific regions have been associated with specific types of delusions. The volume of the hippocampus and parahippocampus is related to paranoid delusions in Alzheimer's disease, and has been reported to be abnormal post mortem in one person with delusions. Capragas delusions have been associated with occipito-temporal damage, and may be related to failure to elicit normal emotions or memories in response to faces.BOOK, Naasan, George, vanc, The Anatomy of Delusions, Lehner T, Miller B, State M, Genomics, Circuits, and Pathways in Clinical Neuropsychiatry, Elsevier Science, 366–369,

Negative symptoms

Psychosis is associated with ventral striatal hypoactivity during reward anticipation and feedback. Hypoactivity in the left ventral striatum is correlated with the severity of negative symptoms.JOURNAL, Radua J, Schmidt A, Borgwardt S, Heinz A, Schlagenhauf F, McGuire P, Fusar-Poli P, Ventral Striatal Activation During Reward Processing in Psychosis: A Neurofunctional Meta-Analysis, JAMA Psychiatry, 72, 12, 1243–51, December 2015, 26558708, 10.1001/jamapsychiatry.2015.2196, While anhedonia is a commonly reported symptom in psychosis, hedonic experiences are actually intact in most people with schizophrenia. The impairment that may present itself as anhedonia probably actually lies in the inability to identify goals, and to identify and engage in the behaviors necessary to achieve goals.BOOK, Young, Jared, Anticevic, Alan, Barch, Deanna, Charney, Dennis, Sklar, Pamela, Nestler, Eric, Buxbaum, Joseph, vanc, Neurobiology of Mental Illness, Oxford University Press, 5th, Cognitive and Motivational Neuroscience of Psychotic Disorders, Studies support a deficiency in the neural representation of goals and goal directed behavior by demonstrating that receipt (not anticipation) of reward is associated with robust response in the ventral striatum; reinforcement learning is intact when contingencies are implicit, but not when they require explicit processing; reward prediction errors (during functional neuroimaging studies), particularly positive PEs are abnormal; ACC response, taken as an indicator of effort allocation, does not increase with reward or reward probability increase, and is associated with negative symptoms; deficits in dlPFC activity and failure to improve performance on cognitive tasks when offered monetary incentives are present; and dopamine mediated functions are abnormal.


Psychosis has been traditionally linked to the neurotransmitter dopamine. In particular, the dopamine hypothesis of psychosis has been influential and states that psychosis results from an overactivity of dopamine function in the brain, particularly in the mesolimbic pathway. The two major sources of evidence given to support this theory are that dopamine receptor D2 blocking drugs (i.e., antipsychotics) tend to reduce the intensity of psychotic symptoms, and that drugs that accentuate dopamine release, or inhibit its reuptake (such as amphetamines and cocaine) can trigger psychosis in some people (see stimulant psychosis).JOURNAL, Kapur S, Mizrahi R, Li M, From dopamine to salience to psychosis--linking biology, pharmacology and phenomenology of psychosis, Schizophrenia Research, 79, 1, 59–68, November 2005, 16005191, 10.1016/j.schres.2005.01.003, NMDA receptor dysfunction has been proposed as a mechanism in psychosis.JOURNAL, Egerton A, Fusar-Poli P, Stone JM, Glutamate and psychosis risk, Current Pharmaceutical Design, 18, 4, 466–78, 2012, 22239577, 10.2174/138161212799316244, This theory is reinforced by the fact that dissociative NMDA receptor antagonists such as ketamine, PCP and dextromethorphan (at large overdoses) induce a psychotic state. The symptoms of dissociative intoxication are also considered to mirror the symptoms of schizophrenia, including negative psychotic symptoms.JOURNAL, Bergeron R, Coyle JT, NAAG, NMDA receptor and psychosis, Current Medicinal Chemistry, 19, 9, 1360–4, 2012, 22304714, 3424071, 10.2174/092986712799462685, NMDA receptor antagonism, in addition to producing symptoms reminiscent of psychosis, mimics the neurophysiological aspects, such as reduction in the amplitude of P50, P300, and MMN evoked potentials.JOURNAL, Adams RA, Stephan KE, Brown HR, Frith CD, Friston KJ, The computational anatomy of psychosis, Frontiers in Psychiatry, 4, 47, 2013, 23750138, 3667557, 10.3389/fpsyt.2013.00047, Hierarchical Bayesian neurocomputational models of sensory feedback, in agreement with neuroimaging literature, link NMDA receptor hypofunction to delusional or hallucinatory symptoms via proposing a failure of NMDA mediated top down predictions to adequately cancel out enhanced bottom up AMPA mediated predictions errors.JOURNAL, Corlett PR, Frith CD, Fletcher PC, From drugs to deprivation: a Bayesian framework for understanding models of psychosis, Psychopharmacology, 206, 4, 515–30, November 2009, 19475401, 2755113, 10.1007/s00213-009-1561-0, Excessive prediction errors in response to stimuli that would normally not produce such as response is thought to confer excessive salience to otherwise mundane events.JOURNAL, Corlett PR, Honey GD, Krystal JH, Fletcher PC, Glutamatergic model psychoses: prediction error, learning, and inference, Neuropsychopharmacology, 36, 1, 294–315, January 2011, 20861831, 3055519, 10.1038/npp.2010.163, Dsyfunction higher up in the hierarchy, where representation is more abstract, could result in delusions.JOURNAL, Corlett PR, Taylor JR, Wang XJ, Fletcher PC, Krystal JH, Toward a neurobiology of delusions, Progress in Neurobiology, 92, 3, 345–69, November 2010, 20558235, 3676875, 10.1016/j.pneurobio.2010.06.007, The common finding of reduced GAD67 expression in psychotic disorders may explain enhanced AMPA mediated signaling, caused by reduced GABAergic inhibition.JOURNAL, Kalkman HO, Loetscher E, GAD(67): the link between the GABA-deficit hypothesis and the dopaminergic- and glutamatergic theories of psychosis, Journal of Neural Transmission, 110, 7, 803–12, July 2003, 12811640, 10.1007/s00702-003-0826-8, JOURNAL, Akbarian S, Huang HS, Molecular and cellular mechanisms of altered GAD1/GAD67 expression in schizophrenia and related disorders, Brain Research Reviews, 52, 2, 293–304, September 2006, 16759710, 10.1016/j.brainresrev.2006.04.001, The connection between dopamine and psychosis is generally believed complex. While dopamine receptor D2 suppresses adenylate cyclase activity, the D1 receptor increases it. If D2-blocking drugs are administered the blocked dopamine spills over to the D1 receptors. The increased adenylate cyclase activity affects genetic expression in the nerve cell, which takes time. Hence antipsychotic drugs take a week or two to reduce the symptoms of psychosis. Moreover, newer and equally effective antipsychotic drugs actually block slightly less dopamine in the brain than older drugs whilst also blocking 5-HT2A receptors, suggesting the 'dopamine hypothesis' may be oversimplified.JOURNAL, Jones HM, Pilowsky LS, Dopamine and antipsychotic drug action revisited, The British Journal of Psychiatry, 181, 4, 271–5, October 2002, 12356650, 10.1192/bjp.181.4.271, Soyka and colleagues found no evidence of dopaminergic dysfunction in people with alcohol-induced psychosisJOURNAL, Soyka M, Zetzsche T, Dresel S, Tatsch K, FDG-PET and IBZM-SPECT suggest reduced thalamic activity but no dopaminergic dysfunction in chronic alcohol hallucinosis, The Journal of Neuropsychiatry and Clinical Neurosciences, 12, 2, 287–8, May 2000, 11001615, 10.1176/appi.neuropsych.12.2.287, and Zoldan et al. reported moderately successful use of ondansetron, a 5-HT3 receptor antagonist, in the treatment of levodopa psychosis in Parkinson's disease patients.JOURNAL, Zoldan J, Friedberg G, Livneh M, Melamed E, Psychosis in advanced Parkinson's disease: treatment with ondansetron, a 5-HT3 receptor antagonist, Neurology, 45, 7, 1305–8, July 1995, 7617188, 10.1212/WNL.45.7.1305, A review found an association between a first-episode of psychosis and prediabetes.JOURNAL, Perry BI, McIntosh G, Weich S, Singh S, Rees K, The association between first-episode psychosis and abnormal glycaemic control: systematic review and meta-analysis, The Lancet. Psychiatry, 3, 11, 1049–1058, November 2016, 27720402, 10.1016/S2215-0366(16)30262-0, Prolonged or high dose use of psychostimulants can alter normal functioning, making it similar to the manic phase of bipolar disorder.JOURNAL, Curran C, Byrappa N, McBride A, Stimulant psychosis: systematic review, The British Journal of Psychiatry, 185, 3, 196–204, September 2004, 15339823, 10.1192/bjp.185.3.196, NMDA antagonists replicate some of the so-called "negative" symptoms like thought disorder in subanesthetic doses (doses insufficient to induce anesthesia), and catatonia in high doses. Psychostimulants, especially in one already prone to psychotic thinking, can cause some "positive" symptoms, such as delusional beliefs, particularly those persecutory in nature.


To make a diagnosis of a mental illness in someone with psychosis other potential causes must be excluded.WEB, Freudenreich, Oliver, Differential Diagnosis of Psychotic Symptoms: Medical "Mimics",weblink Psychiatric Times, UBM Medica, 3 December 2012, 16 March 2017, An initial assessment includes a comprehensive history and physical examination by a health care provider. Tests may be done to exclude substance use, medication, toxins, surgical complications, or other medical illnesses. A person with psychosis is referred to as psychotic.Delirium should be ruled out, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, indicating other underlying factors, including medical illnesses.NEWS, Nordqvist, Christian, vanc, What Is Schizoaffective Disorder? What Causes Schizoaffective Disorder?,weblink March 16, 2017, Medical News Today, August 8, 2016, Excluding medical illnesses associated with psychosis is performed by using blood tests to measure: Other investigations include: Because psychosis may be precipitated or exacerbated by common classes of medications, medication-induced psychosis should be ruled out, particularly for first-episode psychosis. Both substance- and medication-induced psychosis can be excluded to a high level of certainty, using toxicology screening.Because some dietary supplements may also induce psychosis or mania, but cannot be ruled out with laboratory tests, a psychotic individual's family, partner, or friends should be asked whether the patient is currently taking any dietary supplements.JOURNAL, Final rule declaring dietary supplements containing ephedrine alkaloids adulterated because they present an unreasonable risk. Final rule, Federal Register, 69, 28, 6787–854, February 2004, 14968803,weblink Food and Drug Administration, Food Drug Administration, HHS, ({{Federal Register|69|6814}} and {{Federal Register|69|6818}})Common mistakes made when diagnosing people who are psychotic include:
  • Not properly excluding delirium,
  • Not appreciating medical abnormalities (e.g., vital signs),
  • Not obtaining a medical history and family history,
  • Indiscriminate screening without an organizing framework,
  • Missing a toxic psychosis by not screening for substances and medications,
  • Not asking family or others about dietary supplements,
  • Premature diagnostic closure, and
  • Not revisiting or questioning the initial diagnostic impression of primary psychiatric disorder.
Only after relevant and known causes of psychosis are excluded, a mental health clinician may make a psychiatric differential diagnosis using a person's family history, incorporating information from the person with psychosis, and information from family, friends, or significant others.Types of psychosis in psychiatric disorders may be established by formal rating scales. The Brief Psychiatric Rating Scale (BPRS)Overall JE, Gorham DR. The Brief Psychiatric Rating Scale. Psychol Rep. 1962;10:799–812 assesses the level of 18 symptom constructs of psychosis such as hostility, suspicion, hallucination, and grandiosity. It is based on the clinician's interview with the patient and observations of the patient's behavior over the previous 2–3 days. The patient's family can also answer questions on the behavior report. During the initial assessment and the follow-up, both positive and negative symptoms of psychosis can be assessed using the 30 item Positive and Negative Symptom Scale (PANSS).JOURNAL, Kay SR, Fiszbein A, Opler LA, The positive and negative syndrome scale (PANSS) for schizophrenia, Schizophrenia Bulletin, 13, 2, 261–76, 1987, 3616518, 10.1093/schbul/13.2.261, The DSM-5 characterizes disorders as psychotic or on the schizophrenia spectrum if they involve hallucinations, delusions, disorganized thinking, grossly disorganized motor behavior, or negative symptoms.BOOK, Association, American Psychiatric, Diagnostic and statistical manual of mental disorders : DSM-5., 2013, American Psychiatric Association, Washington, D.C., 978-0-89042-554-1, 125, 5th, The DSM-5 does not include psychosis as a definition in the glossary, although it defines "psychotic features", as well as "psychoticism" with respect to personality disorder. The ICD-10 has no specific definition of psychosis.JOURNAL, Gaebel W, Zielasek J, Focus on psychosis, Dialogues in Clinical Neuroscience, 17, 1, 9–18, March 2015, 25987859, 4421906, Factor analysis of symptoms generally regarded as psychosis frequently yields a five factor solution, albeit five factors that are distinct from the five domains defined by the DSM-5 to encompass psychotic or schizophrenia spectrum disorders. The five factors are frequently labeled as hallucinations, delusions, disorganization, excitement, and emotional distress. The DSM-5 emphasizes a psychotic spectrum, wherein the low end is characterized by schizoid personality disorder, and the high end is characterized by schizophrenia.


The evidence for the effectiveness of early interventions to prevent psychosis appeared inconclusive.JOURNAL, Marshall M, Rathbone J, Early intervention for psychosis, The Cochrane Database of Systematic Reviews, 6, CD004718, June 2011, 21678345, 4163966, 10.1002/14651858.CD004718.pub3, But psychosis caused by drugs can be prevented.WEB,weblink Psychosis - Prevention - NHS Choices, NHS,, en, 2018-10-15, Whilst early intervention in those with a psychotic episode might improve short term outcomes, little benefit was seen from these measures after five years.JOURNAL, van Os J, Kapur S, Schizophrenia, Lancet, 374, 9690, 635–45, August 2009, 19700006, 10.1016/S0140-6736(09)60995-8, However, there is evidence that cognitive behavioral therapy (CBT) may reduce the risk of becoming psychotic in those at high risk,JOURNAL, Stafford MR, Jackson H, Mayo-Wilson E, Morrison AP, Kendall T, Early interventions to prevent psychosis: systematic review and meta-analysis, BMJ, 346, f185, January 2013, 23335473, 3548617, 10.1136/bmj.f185, and in 2014 the UK National Institute for Health and Care Excellence (NICE) recommended preventive CBT for people at risk of psychosis.WEB,weblink Offer talking therapies to people at risk of psychosis and schizophrenia,, 2014-02-12, 2014-04-15, WEB,weblink Psychosis and schizophrenia in adults,, 2014-03-31, 2014-04-15,


The treatment of psychosis depends on the specific diagnosis (such as schizophrenia, bipolar disorder or substance intoxication). The first-line treatment for many psychotic disorders is antipsychotic medication,WEB,weblink Schizophrenia: Full national clinical guideline on core interventions in primary and secondary care, 25 November 2009, National Collaborating Centre for Mental Health, 25 March 2009, which can reduce the positive symptoms of psychosis in about 7 to 14 days.


The choice of which antipsychotic to use is based on benefits, risks, and costs. It is debatable whether, as a class, typical or atypical antipsychotics are better.JOURNAL, Kane JM, Correll CU, Pharmacologic treatment of schizophrenia, Dialogues in Clinical Neuroscience, 12, 3, 345–57, 2010, 20954430, 3085113, JOURNAL, Hartling L, Abou-Setta AM, Dursun S, Mousavi SS, Pasichnyk D, Newton AS, Antipsychotics in adults with schizophrenia: comparative effectiveness of first-generation versus second-generation medications: a systematic review and meta-analysis, Annals of Internal Medicine, 157, 7, 498–511, October 2012, 22893011, 10.7326/0003-4819-157-7-201210020-00525, Tentative evidence supports that amisulpride, olanzapine, risperidone and clozapine may be more effective for positive symptoms but result in more side effects. Typical antipsychotics have equal drop-out and symptom relapse rates to atypicals when used at low to moderate dosages.JOURNAL, Schultz SH, North SW, Shields CG, Schizophrenia: a review, American Family Physician, 75, 12, 1821–9, June 2007, 17619525, There is a good response in 40–50%, a partial response in 30–40%, and treatment resistance (failure of symptoms to respond satisfactorily after six weeks to two or three different antipsychotics) in 20% of people.JOURNAL, Smith T, Weston C, Lieberman J, Schizophrenia (maintenance treatment), American Family Physician, 82, 4, 338–9, August 2010, 20704164, Clozapine is an effective treatment for those who respond poorly to other drugs ("treatment-resistant" or "refractory" schizophrenia),JOURNAL, Taylor DM, Duncan-McConnell D, Refractory schizophrenia and atypical antipsychotics, Journal of Psychopharmacology, 14, 4, 409–18, 2000, 11198061, 10.1177/026988110001400411, but it has the potentially serious side effect of agranulocytosis (lowered white blood cell count) in less than 4% of people.JOURNAL, Picchioni MM, Murray RM, Schizophrenia, BMJ, 335, 7610, 91–5, July 2007, 17626963, 1914490, 10.1136/bmj.39227.616447.BE, JOURNAL, Essali A, Al-Haj Haasan N, Li C, Rathbone J, Clozapine versus typical neuroleptic medication for schizophrenia, The Cochrane Database of Systematic Reviews, 1, CD000059, January 2009, 19160174, 10.1002/14651858.CD000059.pub2, Most people on antipsychotics get side effects. People on typical antipsychotics tend to have a higher rate of extrapyramidal side effects while some atypicals are associated with considerable weight gain, diabetes and risk of metabolic syndrome; this is most pronounced with olanzapine, while risperidone and quetiapine are also associated with weight gain.JOURNAL, Barry SJ, Gaughan TM, Hunter R, Schizophrenia, BMJ Clinical Evidence, 2012, June 2012, 23870705, 3385413,weblinkweblink" title="">weblink yes, 2014-09-11, Risperidone has a similar rate of extrapyramidal symptoms to haloperidol.


Psychological treatments such as acceptance and commitment therapy (ACT) are possibly useful in the treatment of psychosis, helping people to focus more on what they can do in terms of valued life directions despite challenging symptomology.JOURNAL, Ost LG, The efficacy of Acceptance and Commitment Therapy: an updated systematic review and meta-analysis, Behaviour Research and Therapy, 61, 105–21, October 2014, 25193001, 10.1016/j.brat.2014.07.018,

Early intervention

Early intervention in psychosis is based on the observation that identifying and treating someone in the early stages of a psychosis can improve their longer term outcome.JOURNAL, Birchwood M, Todd P, Jackson C, Early intervention in psychosis. The critical period hypothesis, The British Journal of Psychiatry. Supplement, 172, 33, 53–9, 1998, 9764127, 10.1192/S0007125000297663, This approach advocates the use of an intensive multi-disciplinary approach during what is known as the critical period, where intervention is the most effective, and prevents the long term morbidity associated with chronic psychotic illness.



The word psychosis was introduced to the psychiatric literature in 1841 by Karl Friedrich Canstatt in his work Handbuch der Medizinischen Klinik. He used it as a shorthand for 'psychic neurosis'. At that time neurosis meant any disease of the nervous system, and Canstatt was thus referring to what was considered a psychological manifestation of brain disease.JOURNAL, Bürgy M, The concept of psychosis: historical and phenomenological aspects, Schizophrenia Bulletin, 34, 6, 1200–10, November 2008, 18174608, 2632489, 10.1093/schbul/sbm136, Ernst von Feuchtersleben is also widely credited as introducing the term in 1845,JOURNAL, Beer MD, Psychosis: from mental disorder to disease concept, History of Psychiatry, 6, 22 Pt 2, 177–200, June 1995, 11639691, 10.1177/0957154X9500602204, as an alternative to insanity and mania.The term stems from Modern Latin psychosis, "a giving soul or life to, animating, quickening" and that from Ancient Greek ψυχή (psyche), "soul" and the suffix -ωσις (-osis), in this case "abnormal condition".WEB,weblink Psychosis, Henry George Liddell, Robert Scott, A Greek-English Lexicon, at Perseus,, 2011-06-11, WEB, Online Etymology Dictionary, Douglas Harper, 2001,weblink 2006-08-19, In its adjective form "psychotic", references to psychosis can be found in both clinical and non-clinical discussions.


The word was also used to distinguish a condition considered a disorder of the mind, as opposed to neurosis, which was considered a disorder of the nervous system.JOURNAL, Berrios GE, Historical aspects of psychoses: 19th century issues, British Medical Bulletin, 43, 3, 484–98, July 1987, 3322481, 10.1093/oxfordjournals.bmb.a072197, The psychoses thus became the modern equivalent of the old notion of madness, and hence there was much debate on whether there was only one (unitary) or many forms of the new disease.JOURNAL, Berrios GE, Beer D, The notion of a unitary psychosis: a conceptual history, History of Psychiatry, 5, 17 Pt 1, 13–36, March 1994, 11639278, 10.1177/0957154X9400501702, One type of broad usage would later be narrowed down by Koch in 1891 to the 'psychopathic inferiorities'—later renamed abnormal personalities by Schneider.The division of the major psychoses into manic depressive illness (now called bipolar disorder) and dementia praecox (now called schizophrenia) was made by Emil Kraepelin, who attempted to create a synthesis of the various mental disorders identified by 19th century psychiatrists, by grouping diseases together based on classification of common symptoms. Kraepelin used the term 'manic depressive insanity' to describe the whole spectrum of mood disorders, in a far wider sense than it is usually used today.In Kraepelin's classification this would include 'unipolar' clinical depression, as well as bipolar disorder and other mood disorders such as cyclothymia. These are characterised by problems with mood control and the psychotic episodes appear associated with disturbances in mood, and patients often have periods of normal functioning between psychotic episodes even without medication. Schizophrenia is characterized by psychotic episodes that appear unrelated to disturbances in mood, and most non-medicated patients show signs of disturbance between psychotic episodes.


Early civilizations considered madness a supernaturally inflicted phenomenon. Archaeologists have unearthed skulls with clearly visible drillings, some datable back to 5000 BC suggesting that trepanning was a common treatment for psychosis in ancient times.BOOK, Porter, Roy, vanc, Madness: A Brief History, 2003, Oxford University Press, US, 978-0-19-280267-5, 10, Written record of supernatural causes and resultant treatments can be traced back to the New Testament. Mark 5:8–13 describes a man displaying what would today be described as psychotic symptoms. Christ cured this "demonic madness" by casting out the demons and hurling them into a herd of swine. Exorcism is still utilized in some religious circles as a treatment for psychosis presumed to be demonic possession.JOURNAL, Vlachos IO, Beratis S, Hartocollis P, Magico-religious beliefs and psychosis, Psychopathology, 30, 2, 93–9, 1997, 9168565, 10.1159/000285035, A research study of out-patients in psychiatric clinics found that 30 percent of religious patients attributed the cause of their psychotic symptoms to evil spirits. Many of these patients underwent exorcistic healing rituals that, though largely regarded as positive experiences by the patients, had no effect on symptomology. Results did, however, show a significant worsening of psychotic symptoms associated with exclusion of medical treatment for coercive forms of exorcism.JOURNAL, Pfeifer S, Belief in demons and exorcism in psychiatric patients in Switzerland, The British Journal of Medical Psychology, 67, 3, 247–58, September 1994, 7803317, 10.1111/j.2044-8341.1994.tb01794.x, The medical teachings of the fourth-century philosopher and physician Hippocrates of Cos proposed a natural, rather than supernatural, cause of human illness. In Hippocrates' work, the Hippocratic corpus, a holistic explanation for health and disease was developed to include madness and other "diseases of the mind." Hippocrates writes:Hippocrates espoused a theory of humoralism wherein disease is resultant of a shifting balance in bodily fluids including blood, phlegm, black bile, and yellow bile.JOURNAL, Bennet S, Mind and madness in classical antiquity, History of Psychiatry and Medical Psychology, 2008, 175–197, 10.1007/978-0-387-34708-0_3, 978-0-387-34707-3, According to humoralism, each fluid or "humour" has temperamental or behavioral correlates. In the case of psychosis, symptoms are thought to be caused by an excess of both blood and yellow bile. Thus, the proposed surgical intervention for psychotic or manic behavior was bloodletting.JOURNAL, Spring B, Weinstein L, Lemon M, Haskell A, Schizophrenia from Hippocrates to Kraepelin, Clinical Psychology, 1991, 259–277, 10.1007/978-1-4757-9715-2_10, 978-1-4757-9717-6, 18th century physician, educator, and widely considered "founder of American psychiatry", Benjamin Rush, also prescribed bloodletting as a first-line treatment for psychosis. Although not a proponent of humoralism, Rush believed that active purging and bloodletting were efficacious corrections for disruptions in the circulatory system, a complication he believed was the primary cause of "insanity".BOOK, Rush, Benjamin, vanc, Medical Inquiries and Observations upon Diseases of the Mind, 1830, Philadelphia, 978-0-559-92167-4, 98–190, Although Rush's treatment modalities are now considered antiquated and brutish, his contributions to psychiatry, namely the biological underpinnings of psychiatric phenomenon including psychosis, have been invaluable to the field. In honor of such contributions, Benjamin Rush's image is in the official seal of the American Psychiatric Association.Early 20th century treatments for severe and persisting psychosis were characterized by an emphasis on shocking the nervous system. Such therapies include insulin shock therapy, cardiazol shock therapy, and electroconvulsive therapy.BOOK, Shorter, Edward, A History of Psychiatry: From the Era of the Asylum to the Age of Prozac, 1998, John Wiley & Sons, Hoboken, New Jersey, 978-0-471-24531-5, Despite considerable risk, shock therapy was considered highly efficacious in the treatment of psychosis including schizophrenia. The acceptance of high-risk treatments led to more invasive medical interventions including psychosurgery.JOURNAL, Stone JL, Dr. Gottlieb Burckhardt--the pioneer of psychosurgery, Journal of the History of the Neurosciences, 10, 1, 79–92, March 2001, 11446267, 10.1076/jhin., In 1888, Swiss psychiatrist Gottlieb Burckhardt performed the first medically sanctioned psychosurgery in which the cerebral cortex was excised. Although some patients showed improvement of symptoms and became more subdued, one patient died and several developed aphasia or seizure disorders. Burckhardt would go on to publish his clinical outcomes in a scholarly paper. This procedure was met with criticism from the medical community and his academic and surgical endeavors were largely ignored.JOURNAL, Gross D, Schäfer G, Egas Moniz (1874-1955) and the "invention" of modern psychosurgery: a historical and ethical reanalysis under special consideration of Portuguese original sources, Neurosurgical Focus, 30, 2, E8, February 2011, 21284454, 10.3171/2011.3.FOCUS10214a, In the late 1930s, Egas Moniz conceived the leucotomy (AKA prefrontal lobotomy) in which the fibers connecting the frontal lobes to the rest of the brain were severed. Moniz’s primary inspiration stemmed from a demonstration by neuroscientists John Fulton and Carlyle’s 1935 experiment in which two chimpanzees were given leucotomies and pre and post surgical behavior was compared. Prior to the leucotomy, the chimps engaged in typical behavior including throwing feces and fighting. After the procedure, both chimps were pacified and less violent. During the Q&A, Moniz asked if such a procedure could be extended to human subjects, a question that Fulton admitted was quite startling.BOOK, Pressman, Jack David, vanc, Last Resort: Psychosurgery and the Limits of Medicine, Cambridge Studies in the History of Medicine, 1998, Cambridge University Press, Cambridge, UK, 978-0-521-35371-7, 36729044, 18–40, Moniz would go on to extend the controversial practice to humans suffering from various psychotic disorders, an endeavor for which he received a Nobel Prize in 1949.JOURNAL, Berrios GE, The origins of psychosurgery: Shaw, Burckhardt and Moniz, History of Psychiatry, 8, 29 pt 1, 61–81, March 1997, 11619209, 10.1177/0957154X9700802905, Between the late 1930s and early 1970s, the leucotomy was a widely accepted practice, often performed in non-sterile environments such as small outpatient clinics and patient homes. Psychosurgery remained standard practice until the discovery of antipsychotic pharmacology in the 1950s.JOURNAL, Mashour GA, Walker EE, Martuza RL, Psychosurgery: past, present, and future, Brain Research. Brain Research Reviews, 48, 3, 409–19, June 2005, 15914249, 10.1016/j.brainresrev.2004.09.002, The first clinical trial of antipsychotics (also commonly known as neuroleptics) for the treatment of psychosis took place in 1952. Chlorpromazine (brand name: Thorazine) passed clinical trials and became the first antipsychotic medication approved for the treatment of both acute and chronic psychosis. Although the mechanism of action was not discovered until 1963, the administration of chlorpromazine marked the advent of the dopamine antagonist, or first generation antipsychotic.JOURNAL, Stip E, Happy birthday neuroleptics! 50 years later: la folie du doute, European Psychiatry, 17, 3, 115–9, May 2002, 12052571, 10.1016/S0924-9338(02)00639-9, While clinical trials showed a high response rate for both acute psychosis and disorders with psychotic features, the side-effects were particularly harsh, which included high rates of often irreversible Parkinsonian symptoms such as tardive dyskinesia. With the advent of atypical antipsychotics (also known as second generation antipsychotics) came a dopamine antagonist with a comparable response rate but a far different, though still extensive, side-effect profile that included a lower risk of Parkinsonian symptoms but a higher risk of cardiovascular disease.JOURNAL, Crossley NA, Constante M, McGuire P, Power P, Efficacy of atypical v. typical antipsychotics in the treatment of early psychosis: meta-analysis, The British Journal of Psychiatry, 196, 6, 434–9, June 2010, 20513851, 2878818, 10.1192/bjp.bp.109.066217, Atypical antipsychotics remain the first-line treatment for psychosis associated with various psychiatric and neurological disorders including schizophrenia, bipolar disorder, major depressive disorder, anxiety disorders, dementia, and some autism spectrum disorders.JOURNAL, Maher AR, Maglione M, Bagley S, Suttorp M, Hu JH, Ewing B, Wang Z, Timmer M, Sultzer D, Shekelle PG, Efficacy and comparative effectiveness of atypical antipsychotic medications for off-label uses in adults: a systematic review and meta-analysis, JAMA, 306, 12, 1359–69, September 2011, 21954480, 10.1001/jama.2011.1360, It is now known that dopamine is the primary neurotransmitter implicated in psychotic symptomology. Thus, blocking dopamine receptors (namely, the dopamine D2 receptors) and decreasing dopaminergic activity continues to be an effective but highly unrefined pharmacologic goal of antipsychotics. Recent pharmacological research suggests that the decrease in dopaminergic activity does not eradicate psychotic delusions or hallucinations, but rather attenuates the reward mechanisms involved in the development of delusional thinking; that is, connecting or finding meaningful relationships between unrelated stimuli or ideas. The author of this research paper acknowledges the importance of future investigation:Freud´s former student Wilhelm Reich explored independent insights into the physical effects of neurotic and traumatic upbringing, and published his holistic psychoanalytic treatment with a schizophrenic. With his incorporation of breathwork and insight with the patient, a young woman, she achieved sufficient self-management skills to end the therapy.Reich, Wilhelm, Character Analysis, 437


Psychiatrist David Healy has criticised pharmaceutical companies for promoting simplified biological theories of mental illness that seem to imply the primacy of pharmaceutical treatments while ignoring social and developmental factors that are known important influences in the aetiology of psychosis.BOOK, Healy, David, vanc, David Healy (psychiatrist), The Creation of Psychopharmacology, Harvard University Press, 2002, Cambridge, 978-0-674-00619-5,



Further reading

  • BOOK, Sims A, 2002, Symptoms in the mind: An introduction to descriptive psychopathology, 3rd, Edinburgh, Elsevier Science Ltd., 978-0-7020-2627-0,
  • BOOK, Murray ED, Buttner N, Price BH, Depression and Psychosis in Neurological Practice, Neurology in Clinical Practice, 6th, Bradley WG, Daroff RB, Fenichel GM, Jankovic J, Butterworth Heinemann, April 2012, 978-1-4377-0434-1,
  • BOOK, Williams, Paris, vanc, 2012, Rethinking Madness: Towards a Paradigm Shift In Our Understanding and Treatment of Psychosis, Sky’s Edge Publishing, 978-0-9849867-0-5,

Personal accounts
  • BOOK, Philip K. Dick, Dick PK, 1981, VALIS, London, Gollancz, 978-0-679-73446-8, VALIS, [Semi-autobiographical]
  • BOOK, Kay Redfield Jamison, Jamison KR, 1995, An Unquiet Mind: A Memoir of Moods and Madness, London, Picador, 978-0-679-76330-7,
  • BOOK, Daniel Paul Schreber, Schreber DP, 2000, Memoirs of My Nervous Illness, New York, New York Review of Books., 978-0-940322-20-2,
  • BOOK, Hinshaw SP, 2002, The Years of Silence are Past: My Father's Life with Bipolar Disorder, Cambridge, Cambridge University Press,
  • BOOK, McLean R, 2003, Recovered Not Cured: A Journey Through Schizophrenia, Allen & Unwin, Australia, 978-1-86508-974-4,
  • BOOK, Elyn Saks, Saks ER, 2007, The Center Cannot Hold—My Journey Through Madness, New York, Hyperion, 978-1-4013-0138-5,

External links

{{Medical resources| DiseasesDB = FF|29}}290}}-{{ICD9|299}}| ICDO = | OMIM = 603342| MedlinePlus = 001553| eMedicineSubj = | eMedicineTopic = 608923}} {{OMIM2192430}}| meshName = Psychotic+Disorders| meshNumber = F03.700.675}} {{Psychiatry}}{{Bipolar disorder}}{{Mental and behavioral disorders|selected = schizophrenia}}

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