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."
People experiencing psychosis may report hallucinations or delusional beliefs, and may exhibit personality changes and disorganized thinking. This may be accompanied by unusual or bizarre 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.
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. 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. 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.
The word psychosis was first used by Ernst von Feuchtersleben in 1845 as an alternative to insanity and mania and stems from the Greek psyche (soul) and -osis (diseased or abnormal condition). 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.
According to the DSM-IV-TR, term psychosis has had many definitions in the past, both broad and narrow. The broadest was not being able to meet the demands of everyday life. The narrowest was delusions or hallucinations without insight. A middle ground may be delusions, hallucinations with or with out insight, and well as disorganized behavior or speech. Thus, 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. 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).
Psychosis should be distinguished from:
insanity, which is a legal term denoting that a person is not criminally responsible for his or her actions.
psychopathy, a general term for a range of personality disorders characterized by lack of empathy, socially manipulative behavior, and occasionally criminality or violence. 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, and distorted perception of reality, which rarely occurs in psychopathy.
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.
The DSM-IV-TR lists 9 formal psychotic disorders, but many other disorders may have psychotic symptoms. The formal psychotic disorders are:
2. Schizoaffective disorder
3. Schizophreniform disorder
4. Brief psychotic disorder
6. Shared psychotic disorder (Folie a Deux)
7. Substance induced psychosis
8. Psychosis due to a general medical condition
9. Psychosis - Not otherwise specified
Causes of symptoms of mental illness were customarily classified as "organic" or "functional". Organic conditions were primarily medical or pathophysiological, whereas, functional conditions are primarily psychiatric or psychological. The DSM-IV-TR no longer classifies psychotic disorders as functional or organic. Rather it lists traditional psychotic illnesses, psychosis due to General Medical conditions, and Substance induced psychosis.
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. 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. 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.
General medical causes
Psychosis arising from "organic" (non-psychological) conditions is sometimes known as secondary psychosis. It can be associated with the following pathologies:
Psychotic states may occur after ingesting a variety of substances both legal and illegal and both prescription and non prescription. Psychoactive drug intoxication or withdrawal. Drugs whose use, abuse or withdrawal are implicated include:
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. 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.
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.
People with psychosis may have one or more of the following:
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. 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. 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.
Psychosis may involve delusional beliefs, some of which are or paranoid in nature. 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).
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. 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 or to avoidant coping style. Later studies have found no statistical relationship between insight and cognitive function, either in groups of people who only have schizophrenia, or in groups of psychotic people from various diagnostic categories.
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 (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. 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 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.
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.
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. This increased level of right hemisphere activation has also been found in healthy people who have high levels of paranormal beliefs and in people who report mystical experiences. 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. 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 neurotransmitterdopamine. 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). 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 dissociativeNMDA 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 independently produce psychosis. New antipsychotic drugs which act on glutamate and its 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. Soyka and colleagues found no evidence of dopaminergic dysfunction in people with alcohol-induced psychosis 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.
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.
Some theories regard many psychotic symptoms to be a problem with the perception of ownership of internally generated thoughts and experiences. 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.
The treatment of psychosis depends on the cause or diagnosis or diagnoses (such as schizophrenia, bipolar disorder and/ or substance intoxication). The first line treatment for many psychotic disorders is antipsychotic medication (oral or intramuscular injection), and sometimes hospitalisation is needed. There is growing evidence that cognitive behavior therapy and family therapy 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.
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. 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. 
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