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Medical Encyclopedia:

Psychosis

Definition

Psychosis is a symptom or feature of mental illness typically characterized by radical changes in personality, impaired functioning, and a distorted or non-existent sense of objective reality.

Description

Patients suffering from psychosis have impaired reality testing; that is, they are unable to distinguish personal, subjective experience from the reality of the external world. They experience hallucinations and/or delusions that they believe are real, and may behave and communicate in an inappropriate and incoherent fashion. Psychosis may appear as a symptom of a number of mental disorders, including mood and personality disorders. It is also the defining feature of schizophrenia, schizophreniform disorder, schizoaffective disorder, delusional disorder, and the psychotic disorders (i.e., brief psychotic disorder, shared psychotic disorder, psychotic disorder due to a general medical condition, and substance-induced psychotic disorder).

— Paula Anne Ford-Martin


 
 
Dictionary: psy·cho·sis  (sī-kō'sĭs) pronunciation
n., pl. -ses (-sēz).

A severe mental disorder, with or without organic damage, characterized by derangement of personality and loss of contact with reality and causing deterioration of normal social functioning.


 
Sci-Tech Encyclopedia: Psychosis

Any disorder of higher mental processes of such severity that judgments pertaining to the reality of external events are significantly impaired. A wide range of conditions can bring about a psychotic state. They include schizophrenia, mania, depression, ingestion of drugs, withdrawal from drugs, liver or kidney failure, endocrine disorders, metabolic disorders, and Alzheimer's disease, epilepsy, and other neurologic dysfunctions. The dreams of normal sleep are a form of psychosis.

Psychotic alterations of beliefs are called delusions. Psychotic alterations of perception are referred to as hallucinations. Psychotic states that are due to alcoholism, metabolic diseases, or other medical conditions are frequently accompanied by general mental confusion. On the other hand, psychiatric illnesses and drugs can produce hallucinations and delusions in the absence of general confusion. Few of those symptoms are unique to a particular illness, which can make proper diagnosis difficult and challenging. Correct diagnosis, however, is critical so that appropriate treatment can be provided. See also Addictive disorders; Affective disorders; Alzheimer's disease; Neurotic disorders; Paranoia; Psychotomimetic drug; Schizophrenia.

 
World of the Body: psychosis

The Greek psyche (‘life’ or ‘soul’) today can be translated as ‘mind’. The suffix ‘-osis’ means ‘any illness of’.

The Oxford English Dictionary defines psychosis as:

Any kind of mental affectation or derangement; especially one which cannot be ascribed to organic lesion or neurosis. In modern use, any mental illness or disorder that is accompanied by hallucinations, delusions or mental confusion and a loss of contact with external reality, whether attributable to an organic lesion or not.


The question of how far psychosis is an organic condition of the body or brain has fascinated psychiatrists ever since the term's origins a century and a half ago.

Origin of the term

The mid-nineteenth-century Austrian poet, politician, and psychiatrist, Feuchtersleben, introduced ‘psychosis’ to denote serious mental conditions affecting the personality; it was a subcategory of (Cullen's) neuroses. Psychosis soon comprised conditions besides the insanities and mental handicap, including minor psychological conditions and major organic disorders. Feuchtersleben coined the terms ‘psychosis’ and ‘psychopathy’ as identical terms because they were ‘diseases of the personality’ — and not of the body, nor of the soul or of the mind alone.

Psychosis-neurosis debate

Neurosis was already a popular term, and psychosis and neurosis were soon viewed in conjunction. Psychosis was seen as the psychological aspect of a neurosis — hence psychoneurosis. Thus the confusing picture arose whereby, in the late nineteenth century, there were three terms — psychosis, psychoneurosis, and psychopathy — for the same condition; by the late twentieth century by contrast these terms all referred to separate conditions. The development of this process of change over the course of the century will now be outlined, along with the different types of psychosis that were described.

At the end of the nineteenth century, attempts were made to find organic/cerebral causes for mental illnesses. The trend of ‘organicization’ increased and culminated in the discovery in 1905 that general paralysis was caused by a physical agent (syphilis). However, there remained many mental disorders that had no known organic cause. The term ‘functional’ was applied to these psychoses in 1881 by the German psychiatrist Fuerstner. However, his compatriot, the anatomist Nissl, claimed that ‘in all psychoses of whatever type there are always positive cortical findings’ (i.e. anatomical evidence of pathology). A functional illness therefore meant one that was suspected of having a physical origin, which had not yet been discovered.

By the mid 1920s, in the absence of the discovery of physical causes for Kraepelin's dementia praecox (schizophrenia) or for manic-depressive insanity, Bumke, his successor as Professor of Psychiatry at the world famous Chair in Munich, unequivocally labelled these as functional as opposed to organic illnesses. An examination of the latter should be conducted in the brain, while the study of the former had to be made in the mind, according to Bumke. The highly influential psychiatrist and philosopher Jaspers listed the functional psychoses as schizophrenia, manic-depressive insanity, and epilepsy.

Today, using computerized imaging techniques, we know that functional psychoses are accompanied by organic changes in the brain. This has made the use of the term ‘functional psychosis’ unhelpful. In the nineteenth century, many mental disorders were considered to be due to degeneration, that is ‘being predisposed to a disorder which led to deterioration, either in that individual or in succeeding generations’. These disorders were termed ‘endogenous’, which could apply both to the psychoses and to disorders of personality (psychopathies).

In 1881 the German degenerationist psychiatrist, Schuele, began the process whereby psychoses were associated with the more serious, organic conditions — cerebropsychoses — and psychoneuroses with the less serious ones. Freud emphasized and popularized the ‘psychoneuroses’ at the turn of the century, and the successful treatment of otherwise healthy soldiers suffering from shellshock in World War I established the entity of the neuroses, as they were to become known.

By 1925 Bumke was writing that ‘there has been no such thing as psychoneuroses for a long time. They have been reclassified into nervous reactions (neuroses), nervous constitutional states, psychopathies and functional psychoses.’ The neuroses were further delineated from the psychoses by Jaspers because ‘they do not wholly involve the individual himself, while those which seize upon the individual as a whole are called psychoses … [and] are generally thought to open up a gulf between sickness and health.’

In the early twentieth century, various terms were used for those conditions, which were deemed psychoses but which were not manic- depressive insanity or schizophrenia, but in the main these two remained the recognized ‘mental illnesses’. Some have upheld the significance of atypical psychoses. The recent debate on these psychoses has also generated much renewed research in the unitary theory of mental illness.

Unitary psychosis

In the mid nineteenth century, the unitary psychosis theory referred to a continuum of mental conditions from health to disease and was based on the importance of symptoms. In the twentieth century, by contrast, the term ‘unitary psychosis’ was applied to the two psychoses, schizophrenia and manic-depressive insanity, with the atypical psychoses bridging these two. Contemporary British psychiatrists have split two ways in their views on this question. Some, who analysed symptoms and emphasized the genetic basis of these disorders, have favoured the concept of unitary psychosis. Others, on the basis of neuroimaging, have rejected the unitary theory in favour of three categories of psychosis: congenital dementia praecox with poor prognosis; an adult form of schizophrenia with good prognosis; and bipolar affective disorder.

‘Psychosis’ — useful or not

There are certain problems with the use of ‘psychosis’ in contemporary psychiatry. Firstly, its very definition is difficult because its defining criteria are not specific (Oxford Textbook of Psychiatry). ‘Lack of insight’ is difficult to define. If ‘severity of illness’ is used as a criterion, the problem then arises that conditions falling into the psychosis category can occur in mild as well as severe forms. Moreover, non-psychotic conditions such as obsessional-compulsive disorder can also be very severe. ‘Impaired contact with reality, as evidenced by delusions and hallucinations’ has been considered difficult to apply. Secondly, conditions to which the term refers appear to have little in common, especially from an aetiological viewpoint. For example, some psychoses can be caused by known organic factors, while others represent a severe depressive illness. Thirdly, it may be better to classify an individual condition like schizophrenia as such, rather than as a member of an umbrella term like psychosis. So, recent classifications have renamed paranoid psychosis as paranoid disorder and affective psychosis as bipolar affective disorder. Fourthly, the tenth International Classification of Diseases (ICD 10) no longer distinguishes between psychosis and neurosis.

The arguments for retaining the term are as follows. Firstly, the psychoses are recognizable — as the ICD 10 proposes — by the presence of delusions and hallucinations without the patient having insight into their morbid nature. Secondly, on a purely practical level, psychosis has carried with it less stigma than the alternative term of ‘insanity’. Thirdly, it is very difficult always to use the term ‘disorder’ as an alternative for psychosis. For example, when it comes to the atypical psychoses the term ‘atypical disorder’ or ‘atypical insanity’ is unsatisfactory. Fourthly, the adjectival use of psychosis is a helpful shorthand term. This can be as in ‘psychotic symptom’ (delusion or hallucination) or ‘antipsychotic’ medication. To use ‘severe unipolar depression with delusions, hallucinations, and loss of insight’ as a replacement for ‘psychotic depression’ is cumbersome.

The contemporary British professor of psychiatry, Tyrer, has written that ‘classification stands or falls by its usefulness.’ In the last two decades the psychiatric profession has made many improvements in the sphere of reliability, but it has been said that there has not been comparable progress in the validity of psychiatric diseases. Therefore, there is a continuing need for the ‘umbrella’ categories such as psychosis and neurosis. The danger with an unquestioning use, and one which does not take cognisance of its abuse and attempted reification as a disease concept earlier this century, is that the mistakes of the past are repeated and an overly organic approach is adopted at the expense of a careful consideration of other — for example psychosocial — factors.

In a clinical and pragmatic sense the combination of one of the definitions of psychosis as ‘gross impairment in reality testing’ and the evident possibility in clinical practice of differentiating psychosis from normality, make psychosis a term that is accessible and acceptable, and yet one which does not necessarily carry the longer term or immutable connotations of its fellow term ‘insane’. Thus for the clinician and the man in the street, a psychotic person differs qualitatively from normal, while someone suffering an understandable neurotic or emotional disturbance usually only differs quantitatively from normal. The psychiatric profession should continue to use the term, but its conceptual limitations should not be overlooked.

— M. Dominic Beer

Bibliography

  • Berrios, G. E. and Beer, M. D. (1995). Unitary psychosis concept. In A history of clinical psychiatry. The origin and history of psychiatric disorders, (ed.) G. E. Berrios and R. Porter. Athlone Press, London

See also psychological disorders; psychosomatic illness.

 
Dental Dictionary: psychosis
(sī-kō′sis)
n

A functional or organic kind of mental derangement marked by a severe disturbance of personality involving autistic thinking, loss of contact with reality, delusions or hallucinations.

 
Britannica Concise Encyclopedia: psychosis

Serious mental derangement characterized by defective or lost contact with reality. The primary psychoses are schizophrenia and the delusional disorders (e.g., megalomania), but extreme cases of depression and bipolar disorder, substance-induced delirium, and certain varieties of dementia are also understood to share important features with the psychoses. The major symptoms, aside from delusions and hallucinations, are disorganized speech and behaviour and, often, mood disturbances. Treatment usually consists of medication and counseling in an institutional setting. Compare neurosis.

For more information on psychosis, visit Britannica.com.

 
Columbia Encyclopedia: psychosis
(sīkō'sĭs) , in psychiatry, a broad category of mental disorder encompassing the most serious emotional disturbances, often rendering the individual incapable of staying in contact with reality. Until recently, the term was used in contrast with neurosis, which denoted the “mild” mental disorders which did not interfere significantly with the ability to function normally, or severely impair the individual's conception of reality. In 1980, the American Psychiatric Association made sweeping changes in its classificatory system for psychological disorders, and the opposition between neurosis and psychosis became obsolete. The former classification included functional psychoses including schizophrenia, paranoia, bipolar disorder, and involutional psychotic reactions, where no brain change was detectable with available tools. Today, there are separate categories for schizophrenic disorders, mood disorders (which include bipolar disorder and major depression), and other serious mental disturbances such as delusional disorder. Symptoms of these disorders may include hallucinations and delusions; severe deviations of mood (depression and mania); lack of, or inappropriateness of, emotional response; and severe impairment of judgment. Another type of psychosis involves brief episodes, characterized by an acute onset lasting no longer than a month, usually resulting from situational circumstances such as an earthquake or flood. Nonspecified psychotic disorders include psychotic symptoms, e.g., delusions, hallucinations, or disorganized behavior, that cannot be classified in any other disorder. Drug therapy and electroconvulsive therapy have been successful in the treatment of many patients with serious psychological disorders. Organic psychoses, so called because of the structural deterioration of the brain, include senile dementia and Alzheimer's disease. Occurring in middle to old age, these disorders involve progressive, nonreversible brain damage. Organic brain damage may also result from toxic reactions to such substances as alcohol, PCP, amphetamines, and crack cocaine. In criminal law, the term insanity can be applied to most forms of psychoses, although defenses based on insanity have been relatively rare.

 
Science Dictionary: psychosis
(seye-koh-sis)

A severe mental disorder, more serious than neurosis, characterized by disorganized thought processes, disorientation in time and space, hallucinations, and delusions. Paranoia, manic depression, megalomania, and schizophrenia are all psychoses. One who suffers from psychosis is psychotic.

 
Veterinary Dictionary: psychosis

Pl. psychoses; any major mental disorder of organic or emotional origin, marked by derangement of the personality and loss of contact with reality, often with delusions, hallucinations or illusions.
There is no scientific study of animal psychiatry and no specific psychoses but some well-identified and traumatic vices, e.g. crib-biting, weaving, tail chasing and flank sucking in dogs, are often classified as such. farrowing hysteria in sows seems to be the animal disease with the closest approximation to a derangement of personality.

  • parturient p. of sows — see farrowing hysteria.
 
Word Tutor: psychosis
pronunciation

IN BRIEF: A mental illness in which contact with reality is impaired.

pronunciation A true psychosis must be treated seriously by a qualified mental health professional.

 
Wikipedia: psychosis
For other uses, see Psychosis (disambiguation).
Psychosis
Classification & external resources
ICD-9 290-299
OMIM 603342 608923 603175 192430
MedlinePlus 001553
MeSH F03.700.675

Psychosis is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality". Stedman's Medical Dictionary defines psychosis as "a severe mental disorder, with or without organic damage, characterized by derangement of personality and loss of contact with reality and causing deterioration of normal social functioning."[1]

People experiencing a psychotic episode may report hallucinations or delusional beliefs (e.g., grandiose or paranoid delusions), and may exhibit personality changes and disorganized thinking. This is often accompanied by lack of insight into the unusual or bizarre nature of their behaviour, as well as difficulty with social interaction and impairment in carrying out the activities of daily living.

A wide variety of nervous system stressors, both organic and functional, can cause a psychotic reaction. This has led to the belief that psychosis is the 'fever' of mental illness—a serious but nonspecific indicator.[2][3]

However, most people have unusual and reality-distorting experiences at some point in their lives, without being impaired or even distressed by these experiences. For example, many people have experienced visions of some kind, and some have even found inspiration or religious revelation in them.[4] As a result, it has been argued that psychosis is not fundamentally separate from normal consciousness, but rather, is on a continuum with normal consciousness.[5] In this view, people who are clinically found to be psychotic, may simply be having particularly intense or distressing experiences (see schizotypy).

In pop culture, the term "psychotic" is often used incorrectly to refer to psychopathy.

History

The word psychosis was first used by Ernst von Feuchtersleben in 1845[6] as an alternative to insanity and mania and stems from the Greek psyche (soul) and -osis (diseased or abnormal condition).[7] The word was used to distinguish disorders which were thought to be disorders of the mind, as opposed to neurosis, which was thought to stem from a disorder of the nervous system.

The division of the major psychoses into manic depressive insanity (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 will often have periods of normal functioning between psychotic episodes even without medication. Schizophrenia is characterized by psychotic episodes which appear to be unrelated to disturbances in mood, and most non-medicated patients will show signs of disturbance between psychotic episodes.

During the 1960s and 1970s, psychosis was of particular interest to counterculture critics of mainstream psychiatric practice, who argued that it may simply be another way of constructing reality and is not necessarily a sign of illness. For example, R. D. Laing argued that psychosis is a symbolic way of expressing concerns in situations where such views may be unwelcome or uncomfortable to the recipients. He went on to say that psychosis could be also seen as a transcendental experience with healing and spiritual aspects. Thomas Szasz focused on the social implications of labelling people as psychotic; a label he argues unjustly medicalises different views of reality so such unorthodox people can be controlled by society. Psychoanalysis has a detailed account of psychosis which differs markedly from Psychiatry. Freud and Lacan outlined their perspective on the structure of psychosis in a number of works Lacan and Freud on the structure of psychosis :

In medical practice today, a descriptive approach to psychosis (and to all mental illness) is used, based on behavioral and clinical observations. This approach is adopted in the standard guide to psychiatric diagnoses employed in the United States, the Diagnostic and Statistical Manual of Mental Disorders (DSM). Since the DSM provides a widely-used standard of reference, the description presented here will largely reflect that point of view.

Classification

According to the DSM, psychosis can be a symptom of mental illness, but it is not a mental illness in its own right. For example, people with schizophrenia often experience psychosis, but so can people with bipolar disorder (manic depression), unipolar depression, delirium, or drug withdrawal.[8][2] People diagnosed with these conditions can also have long periods without psychosis. Conversely, psychosis can occur in people who do not have chronic mental illness (e.g. due to an adverse drug reaction or extreme stress).[9]

Psychosis should be distinguished from insanity, which is a legal term denoting that a person is not criminally responsible for his or her actions.[10]

Psychosis should be distinguished from psychopathy, a general term for a range of personality disorders characterised by lack of empathy, socially manipulative behaviour, and occasionally criminality or violence.[11] Despite both being abbreviated to the slang word "psycho", psychosis bears little similarity to the core features of psychopathy, particularly with regard to violence, which rarely occurs in psychosis,[12][13] and distorted perception of reality, which rarely occurs in psychopathy.[14]

Psychosis should also be distinguished from delirium: a psychotic individual may be able to perform actions that require a high level of intellectual effort in clear consciousness, whereas a delirious individual will have impaired memory and cognitive function.

Causes

Causes of mental illness are customarily classified as "organic" or "functional". Organic conditions are primarily medical or pathophysiological, whereas, functional conditions are primarily psychiatric or psychological.

"Functional" causes

Functional causes of psychosis include the following:

A psychotic episode can be significantly affected by mood. For example, people experiencing a psychotic episode in the context of depression may experience persecutory or self-blaming delusions or hallucinations, while people experiencing a psychotic episode in the context of mania may form grandiose delusions.

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.[9] 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.

Sleep deprivation has been linked to psychosis.[15][16][17] However, this is not a risk for most people, who merely experience hypnagogic or hypnopompic hallucinations, i.e. unusual sensory experiences or thoughts that appear during waking or drifting off to sleep. These are normal sleep phenomena and are not considered signs of psychosis.[18]

"Organic" causes

Psychosis arising from "organic" (non-psychological) conditions is sometimes known as secondary psychosis. It can be associated with the following pathologies:

Psychosis can even be caused by apparently innocuous ailments such as flu[48][49] or mumps.[50]

Psychoactive drugs

Psychotic states may occur with Psychoactive drug intoxication or withdrawal. Drugs whose use, abuse or withdrawal are implicated include:

"#wp-_note-diphenhydramine_trip_therapeutic">[54][55][56][57]

Intoxication with drugs that have general depressant effects on the central nervous system (especially alcohol and barbiturates) tend not to cause psychosis during use, and can actually decrease or lessen the impact of symptoms in some people. However, withdrawal from barbiturates and alcohol can be particularly dangerous, leading to psychosis or delirium and other, potentially lethal, withdrawal effects.

Some studies indicate that cannabis use may lower the threshold for psychosis, and thus help to trigger full-blown psychosis in some people.[72] Early studies have been criticized for failing to consider other drugs (such as LSD) that the participants may have used before or during the study, as well as other factors such as pre-existing ("comorbid") mental illness. However, more recent studies with better controls have still found a small increase in risk for psychosis in cannabis users [citation needed].

It is not clear whether this is a causal link, and it is possible that cannabis use only increases the chance of psychosis in people already predisposed to it; or that people with developing psychosis use cannabis to provide temporary relief of their mental discomfort. The fact that cannabis use has increased over the past few decades, whereas the rate of psychosis has not, suggests that a direct causal link is unlikely for all users.[73]

Signs and symptoms

Hallucinations

Hallucinations are defined as sensory perception in the absence of external stimuli. They are different from illusions, or perceptual distortions, which are the misperception of external stimuli.[74] Hallucinations may occur in any of the five senses and take on almost any form, which may include simple sensations (such as lights, colors, tastes, and smells) to more meaningful experiences such as seeing and interacting with fully formed animals and people, hearing voices and complex tactile sensations.

Auditory hallucinations, particularly the experience of hearing voices, are a common and often prominent feature of psychosis. Hallucinated voices may talk about, or to the person, and may involve several speakers with distinct personas. Auditory hallucinations tend to be particularly distressing when they are derogatory, commanding or preoccupying. However, the experience of hearing voices need not always be a negative one. Research has shown that the majority of people who hear voices are not in need of psychiatric help.[75] The Hearing Voices Movement has subsequently been created to support voice hearers, regardless of whether they are considered to have a mental illness or not.

Delusions and paranoia

Psychosis may involve delusional or paranoid beliefs. Karl Jaspers classified psychotic delusions into primary and secondary types. Primary delusions are defined as arising out of the blue and not being comprehensible in terms of normal mental processes, whereas secondary delusions may be understood as being influenced by the person's background or current situation (e.g., ethnic or sexual discrimination, religious beliefs, superstitious belief).[76]

Thought disorder

Formal thought disorder describes an underlying disturbance to conscious thought and is classified largely by its effects on speech and writing. Affected persons may show pressure of speech (speaking incessantly and quickly), derailment or flight of ideas (switching topic mid-sentence or inappropriately), thought blocking, and rhyming or punning.

Lack of insight

One important and puzzling feature of psychosis is usually an accompanying lack of insight into the unusual, strange, or bizarre nature of the person's experience or behaviour.[77] Even in the case of an acute psychosis, people may be completely unaware that their vivid hallucinations and impossible delusions are in any way unrealistic. This is not an absolute, however; insight can vary between individuals and throughout the duration of the psychotic episode.

It was previously believed that lack of insight was related to general cognitive dysfunction[78] or to avoidant coping style.[79] Later studies have found no statistical relationship between insight and cognitive function, either in groups of people who only have schizophrenia,[80] or in groups of psychotic people from various diagnostic categories.[81]

In some cases, particularly with auditory and visual hallucinations, the person experiencing the hallucinations has good insight, which may make the psychotic experience even more terrifying because the person realizes that he or she should not be hearing voices, but is.

Pathophysiology

Brain imaging studies of psychosis, investigating both changes in brain structure and changes in brain function of people undergoing psychotic episodes, have shown mixed results.

The first brain image of an individual with psychosis was completed as far back as 1935 using a technique called pneumoencephalography[82] (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).

More recently, a 2003 study investigating structural changes in the brains of people with psychosis showed there was significant grey matter reduction in the cortex of people before and after they became psychotic.[83] Findings such as these have led to debate about whether psychosis is itself neurotoxic and whether potentially damaging changes to the brain are related to the length of psychotic episode. Recent research has suggested that this is not the case[84] although further investigation is still ongoing.

Functional brain scans have revealed that the areas of the brain that react to sensory perceptions are active during psychosis. For example, a PET or fMRI scan of a person who claims to be hearing voices may show activation in the auditory cortex, or parts of the brain involved in the perception and understanding of speech.[85]

On the other hand, there is not a clear enough psychological definition of belief to make a comparison between different people particularly valid. Brain imaging studies on delusions have typically relied on correlations of brain activation patterns with the presence of delusional beliefs.[86]

One clear finding is that persons with a tendency to have psychotic experiences seem to show increased activation in the right hemisphere of the brain.[87] This increased level of right hemisphere activation has also been found in healthy people who have high levels of paranormal beliefs[88] and in people who report mystical experiences.[89] It also seems to be the case that people who are more creative are also more likely to show a similar pattern of brain activation.[90] Some researchers have been quick to point out that this in no way suggests that paranormal, mystical or creative experiences are in any way by themselves a symptom of mental illness, as it is still not clear what makes some such experiences beneficial whilst others lead to the impairment or distress of diagnosable mental pathology. However, people who have profoundly different experiences of reality or hold unusual views or opinions have traditionally held a complex role in society, with some being viewed as kooks, whilst others are lauded as prophets or visionaries.

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-blocking drugs (i.e. antipsychotics) tend to reduce the intensity of psychotic symptoms, and that drugs which boost dopamine activity (such as amphetamine and cocaine) can trigger psychosis in some people (see amphetamine psychosis).[91] However, increasing evidence in recent times has pointed to a possible dysfunction of the excitory neurotransmitter glutamate, in particular, with the activity of the NMDA receptor. This theory is reinforced by the fact that dissociative NMDA receptor antagonists such as ketamine, PCP and dextromethorphan/detrorphan (at large overdoses) induce a psychotic state more readily than dopinergic stimulants, even at "normal" recreational doses. The symptoms of dissociative intoxication are also considered to mirror the symptoms of schizophrenia more closely, including negative psychotic symptoms than amphetamine psychosis. Dissociative induced psychosis happens on a more reliable and predictable basis than amphetamine psychosis, which usually only occurs in cases of overdose, prolonged use or with sleep deprivation, which can independantly produce psychosis. New antipsychotic drugs which act on glutamate and it's receptors are currently undergoing clinical trials. (See glutamate hypothesis of psychosis)

The connection between dopamine and psychosis is generally believed to be complex. While antipsychotic drugs immediately block dopamine receptors, they usually 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 affecting serotonin function, suggesting the 'dopamine hypothesis' may be oversimplified.[92] Soyka and colleagues found no evidence of dopaminergic dysfunction in people with alcohol-induced psychosis[93] 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.[94]

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 which are known to be important influences in the aetiology of psychosis.[95]

Some theories regard many psychotic symptoms to be a problem with the perception of ownership of internally generated thoughts and experiences.[96] For example, the experience of hearing voices may arise from internally generated speech that is mislabeled by the psychotic person as coming from an external source.

Treatment

The treatment of psychosis often depends on the cause or associated diagnosis (such as schizophrenia or bipolar disorder); however, the first line treatment for psychotic symptoms is generally antipsychotic medication (oral or intramuscular injection), and in some cases hospitalisation. There is growing evidence that cognitive behavior therapy[97] and family therapy[98] can be effective in managing psychotic symptoms. When other treatments for psychosis are ineffective, electroconvulsive therapy (ECT) (aka shock treatment) is sometimes utilized to relieve the underlying symptoms of psychosis due to depression. There is also increasing research suggesting that Animal-Assisted Therapy can contribute to the improvement in general well-being of people with schizophrenia.[99]

Early Intervention in Psychosis

Early Intervention in Psychosis is a relatively new concept based on the observation that identifying and treating someone in the early stages of a psychosis can significantly improve their longer term outcome [100]. 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.

Newer research into the effectiveness of Cognitive Behavioural Therapy during the early pre-cursory stages of psychosis (also known as the 'prodrome' or 'at risk mental state')suggests that such input can prevent or delay the onset of psychosis. However further research in this area is needed. [101]

Further reading

  • Sims, A. (2002) Symptoms in the mind: An introduction to descriptive psychopathology (3rd edition). Edinburgh: Elsevier Science Ltd. ISBN 0-7020-2627-1

Personal accounts

  • Dick, P.K. (1981) VALIS. London: Gollancz. [Semi-autobiographical] ISBN 0-679-73446-5
  • Hinshaw, S.P. (2002) The Years of Silence are Past: My Father's Life with Bipolar Disorder. Cambridge: Cambridge University Press.
  • Jamison, K.R. (1995) An Unquiet Mind: A Memoir of Moods and Madness. London: Picador.
    ISBN 0-679-76330-9
  • Schreber, D.P. (2000) Memoirs of My Nervous Illness. New York: New York Review of Books. ISBN 0-940322-20-X
  • McLean, R (2003) Recovered Not Cured: A Journey Through Schizophrenia. Allen & Unwin. Australia. ISBN 1-86508-974-5
  • The Eden Express by Mark Vonnegut
  • James Tilly Matthews
  • Saks, Elyn R. (2007) The Center Cannot Hold -- My Journey Through Madness. New York: Hyperion. ISBN 978-1-4013-0138-5

Links

References

  1. ^ The American Heritage Stedman's Medical Dictionary. KMLE Medical Dictionary Definition of psychosis.
  2. ^ a b
  3. ^ DeLage, J. (February 1955). "[Moderate psychosis caused by mumps in a child of nine years.]". Laval Médical 20 (2): 175-183. PubMed. 
  4. ^ Dick, P.K. (1981) VALIS. London: Gollancz. ISBN 0-679-73446-5
  5. ^ Johns, Louise C.; Jim van Os (2001). "The continuity of psychotic experiences in the general population.". Clinical Psychology Review 21 (8): 1125-41. PubMed. DOI:10.1016/S0272-7358(01)00103-9. PubMed. Retrieved on 2006-08-19. 
  6. ^ Beer, M D (1995). "Psychosis: from mental disorder to disease concept.". Hist Psychiatry 6 (22(II)): 177-200. PubMed. PMID 11639691. Retrieved on 2006-08-19. 
  7. ^ Online Etymology Dictionary. Douglas Harper (2001). Retrieved on 2006-08-19.
  8. ^ American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth edition - Text Revision (Published by the American Psychiatric Association, 2000).
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