| Psychosis | ||
|---|---|---|
| ICD-10 code: | ||
| ICD-9 code: | 290-299 | |
Psychosis is a generic psychiatric term for mental states in which the components of rational thought and perception are severely impaired. Persons experiencing a psychosis may experience hallucinations, hold delusional beliefs (e.g.paranoid delusions), demonstrate personality changes and exhibit disorganized thinking (see thought disorder). This is often accompanied by lack of insight into the unusual or bizarre nature of such behavior, difficulties with social interaction and impairments in carrying out the activities of daily living. A psychotic episode is often described as involving a "loss of contact with reality".
It is not uncommon in cases of brain injury and may occur after Drug use, particularly after Drug overdose, chronic use, and during drug withdrawal. Certain compounds may be more likely to induce psychosis, and some individuals may show greater sensitivity than others. Drugs can induce true psychosis two ways, due to drug intoxication, or due to drug withdrawal. Anticholinergic drugs (Atropine, Scopolamine, Jimson weed, most antihistamines (diphenhydramine, dimenhydrinate, hydroxizine, etc.) can induce a true psychotic state which will abate once the acute effects of the drug wear off. So, of course, can certain "street" drugs such as PCP, Cocaine, amphetamines and hallucinogens.
Drugs that have general depressant effects on the Central nervous system (especially alcohol and barbiturates) do not induce psychosis during use, and can actually decrease psychotic symptoms, although withdrawal from them can induce a state of hyperactivity that is indistinguishable from psychosis. The withdrawal from barbiturates and alcohol can be particularly dangerous, as not only is there a severe impairment of reality testing with acting out on psychotic delusions, there is also a possibly lethal effect upon the body.
Chronic psychological stress is also known to cause psychotic states, though the exact mechanism is uncertain. Short-lived psychosis triggered by stress is known as Brief reactive psychosis.
The term psychosis should be distinguished from the concept of Insanity, which is a legal term denoting that a person should not be criminally responsible for his actions. Similarly, it should be distinguished from psychopathy, a Personality disorder often associated with violence, lack of Empathy and socially manipulative behavior. Despite the fact that both are colloquially abbreviated to "psycho", psychosis bears little similarity to psychopathy's core features, particularly with regard to violence, which rarely occurs in psychosis, and the distortion of perceived reality, which rarely occurs in psychopathy.
Psychosis should also be distinguished from the state of Delirium, in that a psychotic individual may be able to perform actions that require a high level of intellectual effort in clear consciousness. Finally, it should be distinguished from mental illness. Psychosis may be regarded as a symptom of other mental illnesses, but as a descriptive concept it is not considered an illness in its own right. For example, persons with Schizophrenia can have long periods without psychosis, and persons with Bipolar disorder and depression can have mood symptoms without psychosis. Conversely, psychosis can occur in persons without chronic mental illness, as a result of an adverse drug reaction or extreme stress.
Sleep deprivation has been linked to psychosis, although there is little evidence to suggest that it is a major risk factor in the majority of people. Some people experience hypnagogic or hypnopompic hallucinations, where unusual sensory experierences or thoughts appear during waking or drifting off to sleep. These are normal sleep phenomena, however, and are not considered signs of psychosis.
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. 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. Scientology has repudiated the concept completely.
Generally, however, advances in both differential diagnosis and studies of the biochemistry of psychotic and non-psychotic individuals have established that there are usually underlying, physical causes (not always yet well understood) for the appearance of a psychosis, and that psychotropic intervention can effectively minimize or eliminate the symptomatology within a relatively rapid amount of time, restoring without altering the patient's usual interests, ambitions, dreams, skills, talents and ability to safely conduct his daily life. In the United States and Europe, few reputable practitioners since the 1990s have approached psychosis outside this scientific frame of reference.
Etymology: The word psychosis was first used by Ernst von Feuchtersleben in 1845 as an alternative to Insanity and Mania and stems from the Greek psykhe (mind) 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 nerves.
Although usually distressing and regarded as an illness process, some people who experience psychosis find beneficial aspects and value the experience or revelations that stem from it.
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, as outlined by the Hearing Voices Movement informed by the research of Prof. Marius Romme.
In some cases, particularly with auditory and visual hallucinations, the patient has good insight and this makes the psychotic experience even more terrifying in that the patient realizes that he should not be hearing voices, but does.
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.
Psychotic episodes may vary in duration between individuals. In Brief reactive psychosis, the psychotic episode is related directly to a specific stressful life event, so 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.
Patients who are undergoing a brief psychotic episode may have many of the same symptoms as a person who is psychotic as a result of (for example) schizophrenia, and this fact has been used to support the notion that psychosis is primarily a breakdown in some specific biological system in the brain. The dopamine hypothesis of psychosis was an early, and still popular, example of a theory based on this assumption. However, it is controversial how much weight should be given to such exclusively biological theories as it has become clearer that a wide range of influences (including environmental, social and childhood development factors) may contribute to the final experience of psychosis.
It has also been argued that psychosis exists on a continuum as everybody may have some unusual and potentially reality-distorting experiences in their life. This has been backed up by research showing that experiences such as hallucinations have been experienced by large numbers of the population who may never be impaired or even distressed by their experiences. In this view, people who are diagnosed with a psychotic illness may simply be one end of a spectrum where the experiences become particularly intense or distressing (see Schizotypy).
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Modern brain imaging studies, investigating both changes in brain structure and changes in brain function of people undergoing psychotic episodes, have shown mixed results.
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 reacts 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 or 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).
Nevertheless, the connection between dopamine and psychosis is generally believed to be complex. First of all, while antipsychotic drugs immediately block dopamine receptors, they usually take a week or two to reduce the symptoms of psychosis. Moreover, newer and equally as effective antipsychotic drugs actually block slightly less dopamine in the brain than older drugs whilst also affecting Serotonin function, suggesting the 'dopamine hypothesis' is vastly oversimplified.
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 mislabelled by the psychotic person as coming from an external source.
There are some non-psychiatric conditions which are linked particularly to psychosis, which may include:
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2 Pantelis C, Velakoulis D, McGorry PD, Wood SJ, Suckling J, Phillips LJ, Yung AR, Bullmore ET, Brewer W, Soulsby B, Desmond P, McGuire PK. (2003) Neuroanatomical abnormalities before and after onset of psychosis: a cross-sectional and longitudinal MRI comparison. Lancet, 25, 361 (9354), 281-8.
3 Ho, B. C., Alicata, D., Ward, J., Moser, D. J., O'Leary, D. S., Arndt, S., et al. (2003) Untreated initial psychosis: relation to cognitive deficits and brain morphology in first-episode schizophrenia. American Journal of Psychiatry, 160(1), 142-148.
4 Lohr JB, Caligiuri MP (1997) Lateralized hemispheric dysfunction in the major psychotic disorders: historical perspectives and findings from a study of motor asymmetry in older patients. Schizophrophrenia Research, 30, 27(2-3), 191-8.
5 Pizzagalli, D., Lehmann, D., Gianotti, L., Koenig, T., Tanaka, H., Wackermann, J., et al. (2000) Brain electric correlates of strong belief in paranormal phenomena: intracerebral EEG source and regional Omega complexity analyses. Psychiatry Research, 100(3), 139-154.
6 Makarec, K., & Persinger, M. A. (1985) Temporal lobe signs: electroencephalographic validity and enhanced scores in special populations. Perceptual and Motor Skills, 60(3), 831-842.
7 Weinstein, S., & Graves, R. E. (2002) Are creativity and schizotypy products of a right hemisphere bias? Brain and Cognition, 49(1), 138-151.
8Healy, D. (2002) The Creation of Psychopharmacology. Cambridge, MA: Harvard University Press. ISBN 0674006194
9 Blakemore SJ, Smith J, Steel R, Johnstone CE, Frith CD. (2000) The perception of self-produced sensory stimuli in patients with auditory hallucinations and passivity experiences: evidence for a breakdown in self-monitoring. Psychological Medicine, 30 (5), 1131-9. 10 Johns LC, van Os J. (2001) The continuity of psychotic experiences in the general population. Clinical Psychology Review, 21 (8), 1125-41.
11 Degenhardt, L. (2003) Editorial: The link between cannabis use and psychosis: furthering the debate. Psychological Medicine, 33, 3-6.
12 Tsuang, M. T., Stone, W. S., & Faraone, S. V. (2000) Toward reformulating the diagnosis of schizophrenia. American Journal of Psychiatry, 157(7), 1041-1050.