Psychosis (from the Greek ψυχή "psyche", for mind or soul, and -οσις "-osis", for abnormal condition), with adjective psychotic, literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality". People suffering from psychosis are said to be psychotic.
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 behavior, as well as difficulty with social interaction and impairment in carrying out the activities of daily living.
A wide variety of central nervous system diseases, from both external toxins, and from internal physiologic illness, can produce symptoms of psychosis. This disease link has led to the metaphor of psychosis as the 'fever' of CNS illness—a serious but nonspecific indicator.
However, many people have unusual and distinct (unshared) experiences of different realities 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 contemporary culture, the term "psychotic" is often incorrectly used interchangeably with "psychopathic" (which describes a more long-term condition prone to violence, rarely having hallucinations).
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.
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.
According to the DSM-IV-TR, the 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 without insight, as 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, and some may never experience them again. 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:
The DSM-IV-TR lists 9 formal psychotic disorders, but many other disorders may have psychotic symptoms. The formal psychotic disorders are:
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.
Vitamin B12 deficiency can also cause symptoms of mania and psychosis.
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.
It is also important to this topic to understand the paradoxical effects of some sedative drugs..Serious complications can occur in conjunction with the use of sedatives creating the opposite effect as to that intended. Malcolm Lader at the Institute of Psychiatry in London estimates the incidence of these adverse reactions at about 5%, even in short-term use of the drugs. The paradoxical reactions may consist of depression, with or without suicidal tendencies, phobias, aggressiveness, violent behavior and symptoms sometimes misdiagnosed as psychosis.
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 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). 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 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.
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.
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 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 labeling 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 that of psychiatry. Freud and Lacan outlined their perspective on the structure of psychosis in a number of works.
Since the 1970s, the introduction of a Recovery approach to mental health, which has been driven mainly by people who have experienced psychosis (or whatever name is used to describe their experiences), has led to a greater awareness that mental illness is not a lifelong disability, and that there is an expectation that recovery is possible, and probable with effective support.