Psychosis
Encyclopedia
Psychosis 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 described as psychotic. Psychosis is given to the more severe forms of psychiatric disorder, during which hallucinations and delusions and impaired insight
may occur. Some professionals say that the term psychosis is not sufficient as some illnesses grouped under the term "psychosis" have nothing in common (Gelder, Mayou & Geddes 2005).
People experiencing psychosis may report hallucination
s or delusion
al beliefs, and may exhibit personality changes and thought disorder
. Depending on its severity, this may be accompanied by unusual or bizarre behavior, as well as difficulty with social interaction and impairment in carrying out daily life activities.
A wide variety of central nervous system diseases, from both external poisons and internal physiologic illness, can produce symptoms of psychosis.
s, delusion
s, catatonia
, or a thought disorder
, as described below.
is defined as sensory perception in the absence of external stimuli. Hallucinations are different from illusion
s, 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 experiences such as seeing and interacting with fully formed animals and people, hearing voices, and having complex tactile sensations.
Auditory hallucinations, particularly experiences 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. One research study 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.
al beliefs, some of which are paranoid
in nature. 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 may be understood as being influenced by the person's background or current situation (e.g., ethnicity, religious beliefs, superstitious belief).
describes a profoundly agitated state in which the experience of reality is generally considered to be 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 stays 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 behavior as well as extreme mental preoccupation which prevents intact experience of reality. An example would be 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.
describes an underlying disturbance to conscious thought and is classified largely by its effects on speech and writing. Affected persons show loosening of associations, that is, a disconnection and disorganization of the semantic content of speech and writing. In the severe form speech becomes incomprehensible and it is known as "word-salad".
view of the mind-body problem holds that mental disorders arise from physical processes; in this view, the distinction between brain and mind, and therefore between organic and functional disease, is an artificial one. 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.
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. 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.
Psychosis can even be caused by familiar ailments such as flu or mumps
.
, caffeine
(which can worsen psychotic symptoms in schizophrenia and produce olfactory hallucinations at very high doses in normal volunteers), cannabis
, cocaine
, desoxypipradrol
, dimethyltryptamine
, alcohol
(ethanol), inhalants, gammahydroxybutyric acid (and its precursors gammabutyrolactone and 1,4-butanediol
), ketamine
, LSD
, mephedrone and methcathinone
, mescaline
and other phenethylamine hallucinogens, methamphetamine
, MDMA (very rarely), opiates such as heroin, phencyclidine
, piperazine
-based drugs, psilocybin
, and anabolic steroids at high doses.
Frequent users of cannabis
have twice the likelihood of developing both psychosis and schizophrenia
. Older studies indicate that certain strains containing large proportions of tetrahydrocannabinol and low proportions of cannabidiol merely lowers the threshold for psychosis, and thus helps to trigger full-blown psychosis in some people. On the other hand, cannabis use has increased dramatically over the past few decades but declined in the last decade, whereas the rate of psychosis has not increased. This suggests cannabis generally only hastens the onset of psychosis in those who would otherwise only become psychotic at a later date.
and other sympathomimetics, dopamine
agonists, ketamine
, corticosteroids (often with mood changes in addition), and some anticonvulsants such as vigabatrin
.
(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).
The purpose of the brain is to collect information from the body (pain, hunger, etc.), and from the outside world, interpret it to a coherent world view, and produce a meaningful response. The information from the senses enter the brain in the primary sensory areas
. They process the information and send it to the secondary areas where the information is interpreted. Spontaneous activity in the primary sensory areas may produce hallucinations which are misinterpreted by the secondary areas as information from the real world.
For example, a PET
or fMRI scan of a person who claims to be hearing voices may show activation in the primary auditory cortex, or parts of the brain involved in the perception and understanding of speech.
Tertiary brain cortex collects the interpretations from the secondary cortexes and creates a coherent world view of it. A study investigating structural changes in the brains of people with psychosis showed there was significant grey matter
reduction in the right medial temporal, lateral temporal
, and inferior frontal gyrus
, and in the cingulate cortex
bilaterally of people before and after they became psychotic. Findings such as these have led to debate about whether psychosis itself causes excitotoxic brain damage
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.
Studies with sensory deprivation
have shown that the brain is dependent on signals from the outer world to function properly. If the spontaneous activity in the brain is not counterbalanced with information from the senses, loss from reality and psychosis may occur after some hours. A similar phenomenon is paranoia
in the elderly when poor eyesight, hearing and memory causes the person to be abnormally suspicious of the environment.
On the other hand, loss from reality may also occur if the spontaneous cortical activity is increased so that it is no longer counterbalanced with information from the senses. The 5-HT2A receptor
seems to be important for this, since psychedelic drugs which activate them produce hallucinations.
However, the main feature of psychosis is not hallucinations, but the inability to distinguish between internal and external stimuli. Close relatives to psychotic patients may hear voices, but since they are aware that they are unreal they can ignore them, so that the hallucinations do not affect their reality perception. Hence they are not considered to be psychotic.
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., antipsychotic
s) tend to reduce the intensity of psychotic symptoms, and that drugs which boost dopamine activity (such as amphetamines 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
/dextrorphan
(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, including negative psychotic symptoms, more closely 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.
The connection between dopamine and psychosis is generally believed to be 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, a process 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. 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.
It has been suggested that persons with bipolar disorder
may have increased activity of the left hemisphere compared to the right hemisphere of the brain, while persons with schizophrenia
have increased activity in the right hemisphere.
Increased level of right hemisphere activation has also been found in 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 and others distressing.
The presence of psychosis is typically diagnosed by clinical interview, incorporating mental state examination. Its extent may be established by formal rating scales. The Brief Psychiatric Rating Scale
(BPRS) 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 provide 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).
Establishing the cause of psychosis requires clinical examination, and sometimes special investigations, to diagnose or exclude secondary causes of psychosis; if these are excluded, a primary psychiatric diagnosis can be established.
medication (oral or intramuscular injection), and sometimes hospitalization
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
or ECT (also known as shock treatment) is sometimes applied 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.
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.
and mania
and stems from the Greek
ψύχωσις (psychosis), "a giving soul or life to, animating, quickening" and that from ψυχή (psyche), "soul" and the suffix -ωσις (-osis), in this case "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 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.
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 disorder
s, 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. Arthur J. Deikman
suggested use of the term "mystical psychosis
" to characterize first-person accounts of psychotic experiences that are similar to reports of mystical experiences. 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.
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...
term for a mental state often described as involving a "loss of contact with reality
Reality
In philosophy, reality is the state of things as they actually exist, rather than as they may appear or might be imagined. In a wider definition, reality includes everything that is and has been, whether or not it is observable or comprehensible...
". People suffering from psychosis are described as psychotic. Psychosis is given to the more severe forms of psychiatric disorder, during which hallucinations and delusions and impaired insight
Insight
Insight is the understanding of a specific cause and effect in a specific context. Insight can be used with several related meanings:*a piece of information...
may occur. Some professionals say that the term psychosis is not sufficient as some illnesses grouped under the term "psychosis" have nothing in common (Gelder, Mayou & Geddes 2005).
People experiencing psychosis may report hallucination
Hallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
s or delusion
Delusion
A delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
al beliefs, and may exhibit personality changes and thought disorder
Thought disorder
In psychiatry, thought disorder or formal thought disorder is a term used to describe incomprehensible language, either speech or writing, that is presumed to reflect thinking. There are different types...
. Depending on its severity, this may be accompanied by unusual or bizarre behavior, as well as difficulty with social interaction and impairment in carrying out daily life activities.
A wide variety of central nervous system diseases, from both external poisons and internal physiologic illness, can produce symptoms of psychosis.
Signs and symptoms
People with psychosis may have one or more of the following: hallucinationHallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
s, delusion
Delusion
A delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
s, catatonia
Catatonia
Catatonia is a state of neurogenic motor immobility, and behavioral abnormality manifested by stupor. It was first described in 1874: Die Katatonie oder das Spannungsirresein ....
, or a thought disorder
Thought disorder
In psychiatry, thought disorder or formal thought disorder is a term used to describe incomprehensible language, either speech or writing, that is presumed to reflect thinking. There are different types...
, as described below.
Hallucinations
A hallucinationHallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
is defined as sensory perception in the absence of external stimuli. Hallucinations are different from illusion
Illusion
An illusion is a distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people....
s, 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 experiences such as seeing and interacting with fully formed animals and people, hearing voices, and having complex tactile sensations.
Auditory hallucinations, particularly experiences 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. One research study has shown that the majority of people who hear voices are not in need of psychiatric help. The Hearing Voices Movement
Hearing Voices Movement
Hearing Voices Movement is a philosophical trend in how people who hear voices are viewed. It was begun by Marius Romme, a professor of social psychiatry at the University of Limburg in Maastricht, the Netherlands; and Sandra Escher, a science journalist, who began this work after being challenged...
has subsequently been created to support voice hearers, regardless of whether they are considered to have a mental illness or not.
Delusions
Psychosis may involve delusionDelusion
A delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
al beliefs, some of which are paranoid
Paranoia
Paranoia [] is a thought process believed to be heavily influenced by anxiety or fear, often to the point of irrationality and delusion. Paranoid thinking typically includes persecutory beliefs, or beliefs of conspiracy concerning a perceived threat towards oneself...
in nature. Karl Jaspers
Karl Jaspers
Karl Theodor Jaspers was a German psychiatrist and philosopher who had a strong influence on modern theology, psychiatry and philosophy. After being trained in and practicing psychiatry, Jaspers turned to philosophical inquiry and attempted to discover an innovative philosophical system...
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 may be understood as being influenced by the person's background or current situation (e.g., ethnicity, religious beliefs, superstitious belief).
Catatonia
CatatoniaCatatonia
Catatonia is a state of neurogenic motor immobility, and behavioral abnormality manifested by stupor. It was first described in 1874: Die Katatonie oder das Spannungsirresein ....
describes a profoundly agitated state in which the experience of reality is generally considered to be 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 stays 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 behavior as well as extreme mental preoccupation which prevents intact experience of reality. An example would be 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.
Thought disorder
Thought disorderThought disorder
In psychiatry, thought disorder or formal thought disorder is a term used to describe incomprehensible language, either speech or writing, that is presumed to reflect thinking. There are different types...
describes an underlying disturbance to conscious thought and is classified largely by its effects on speech and writing. Affected persons show loosening of associations, that is, a disconnection and disorganization of the semantic content of speech and writing. In the severe form speech becomes incomprehensible and it is known as "word-salad".
Causes
Causes of symptoms of mental illness were customarily classified as "organic" or "functional." Organic disorders were those held to be caused by physical illness affecting the brain (that is, psychiatric disorders secondary to other conditions), while functional disorders were considered to be disorders of the functioning of the mind in the absence of physical disorders (that is, primary psychological or psychiatric disorders). The materialisticMaterialism
In philosophy, the theory of materialism holds that the only thing that exists is matter; that all things are composed of material and all phenomena are the result of material interactions. In other words, matter is the only substance...
view of the mind-body problem holds that mental disorders arise from physical processes; in this view, the distinction between brain and mind, and therefore between organic and functional disease, is an artificial one. Subtle physical abnormalities have been found in illnesses traditionally considered functional, such as schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
. 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.
Psychiatric disorders
Primary psychiatric causes of psychosis include the following:- schizophreniaSchizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
and schizophreniform disorderSchizophreniform disorderSchizophreniform disorder is a mental disorder diagnosed when symptoms of schizophrenia are present for a significant portion of the time within a one-month period, but signs of disruption are not present for the full six months required for the diagnosis of schizophrenia.The symptoms of both... - affective (mood) disorders, including severe depression, and severe depression or mania in bipolar disorderBipolar disorderBipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
(manic depression). 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. - schizoaffective disorderSchizoaffective disorderSchizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of elevated or depressed mood, or of simultaneously elevated and depressed mood, that alternate with, or occur together with, distortions in perception.Schizoaffective disorder...
, involving symptoms of both schizophrenia and mood disorders - brief psychotic disorderBrief psychotic disorderBrief psychotic disorder is a period of psychosis whose duration is generally shorter, non re-occurring, and not better accounted for by another condition....
, or acute/transient psychotic disorder - delusional disorderDelusional disorderDelusional disorder is an uncommon psychiatric condition in which patients present with circumscribed symptoms of non-bizarre delusions, but with the absence of prominent hallucinations and no thought disorder, mood disorder, or significant flattening of affect...
(persistent delusional disorder) - chronic hallucinatory psychosisChronic hallucinatory psychosisChronic hallucinatory psychosis is a psychosis subtype, classified under "Other nonorganic psychosis" by the ICD-10 Chapter V: Mental and behavioural disorders. Other abnormal mental symptoms in the early stages are, as a rule, absent...
Psychotic symptoms may also be seen in
- schizotypal disorder
- certain personality disorders at times of stress (including paranoid personality disorderParanoid personality disorderParanoid personality disorder is a psychiatric diagnosis characterized by paranoia and a pervasive, long-standing suspiciousness and generalized mistrust of others....
, schizoid personality disorderSchizoid personality disorderSchizoid personality disorder is a personality disorder characterized by a lack of interest in social relationships, a tendency towards a solitary lifestyle, secretiveness, emotional coldness, and sometimes apathy, with a simultaneous rich, elaborate, and exclusively internal fantasy world...
, and borderline personality disorderBorderline personality disorderBorderline personality disorder is a personality disorder described as a prolonged disturbance of personality function in a person , characterized by depth and variability of moods.The disorder typically involves unusual levels of instability in mood; black and white thinking, or splitting; the...
) - major depressive disorder in its severe form although it is possible and more likely to have severe depression without psychosis
- bipolar disorderBipolar disorderBipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
in severe mania and/or severe depression although it is possible to have severe mania and/or severe depression without psychosis as well, in fact that is more commonly the case - post-traumatic stress disorderPost-traumatic stress disorderPosttraumaticstress disorder is a severe anxiety disorder that can develop after exposure to any event that results in psychological trauma. This event may involve the threat of death to oneself or to someone else, or to one's own or someone else's physical, sexual, or psychological integrity,...
- induced delusional disorder
- Sometimes in obsessive-compulsive disorderObsessive-compulsive disorderObsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...
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
Brief reactive psychosis
Brief reactive psychosis - referred to in the DSM IV-TR as "brief psychotic disorder with marked stressor" - is the psychiatric term for psychosis which can be triggered by an extremely stressful event in the life of a patient....
, 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.
Normal states
Brief hallucinations are not uncommon in those without any psychiatric disease. Causes or triggers include- falling asleep and waking: hypnagogic and hypnopompicHypnopompicA hypnopompic state is the state of consciousness leading out of sleep, a term coined by the psychical researcher Frederic Myers. Its twin is the hypnagogic state at sleep onset; though often conflated, the two states are not identical...
hallucinations, which are entirely normal - bereavement, in which hallucinations of a deceased loved one are common
- severe sleep deprivationSleep deprivationSleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
- sensory deprivationSensory deprivationSensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch,...
and sensory impairment - Caffeine Intoxication
Medical conditions
A very large number of medical conditions can cause psychosis, sometimes called secondary psychosis. Examples include:- disorders causing deliriumDeliriumDelirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
(toxic psychosis), in which consciousness is disturbed - neurodevelopmental disorders and chromosomal abnormalities, including velocardiofacial syndrome
- neurodegenerative disorders, such as Alzheimer's diseaseAlzheimer's diseaseAlzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
, dementia with Lewy bodiesDementia with Lewy bodiesDementia with Lewy bodies , also known under a variety of other names including Lewy body dementia, diffuse Lewy body disease, cortical Lewy body disease, and senile dementia of Lewy type, is a type of dementia closely allied to both Alzheimers and Parkinson's Diseases...
, and Parkinson's diseaseParkinson's diseaseParkinson's disease is a degenerative disorder of the central nervous system... - focal neurological disease, such as strokeStrokeA stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, brain tumorBrain tumorA brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...
s, multiple sclerosisMultiple sclerosisMultiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
, and some forms of epilepsyEpilepsyEpilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases... - malignancy (typically via masses in the brain, paraneoplastic syndromes, or drugs used to treat cancer)
- infectious and postinfectious syndromes, including infections causing deliriumDeliriumDelirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
, viral encephalitisViral encephalitisViral encephalitis refers to a type of Encephalitis caused by a virus.Encephalitis may be caused by a variety of afflictions.Types include:*Arbovirus encephalitis**La Crosse encephalitis**California encephalitis virus**Japanese Encephalitis**St...
, HIVHIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
, malariaMalariaMalaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
, Lyme diseaseLyme diseaseLyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
, syphilisSyphilisSyphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis... - endocrine disease, such as hypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, hyperthyroidismHyperthyroidismHyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
, adrenal failure, Cushing's syndromeCushing's syndromeCushing's syndrome is a hormone disorder caused by high levels of cortisol in the blood. This can be caused by taking glucocorticoid drugs, or by tumors that produce cortisol or adrenocorticotropic hormone or CRH...
, hypoparathyroidismHypoparathyroidismHypoparathyroidism is decreased function of the parathyroid glands with under production of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany , and several other symptoms...
and hyperparathyroidismHyperparathyroidismHyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone . The parathyroid hormone regulates calcium and phosphate levels and helps to maintain these levels...
; sex hormones also affect psychotic symptoms and sometimes childbirth can provoke psychosis, termed puerperal psychosis - inborn errors of metabolism, such as porphyriaPorphyriaPorphyrias are a group of inherited or acquired disorders of certain enzymes in the heme bio-synthetic pathway . They are broadly classified as acute porphyrias and cutaneous porphyrias, based on the site of the overproduction and accumulation of the porphyrins...
and metachromatic leukodystrophyMetachromatic leukodystrophyMetachromatic leukodystrophy is a lysosomal storage disease which is commonly listed in the family of leukodystrophies. Leukodystrophies affect the growth and/or development of myelin, the fatty covering which acts as an insulator around nerve fibers throughout the central and peripheral nervous... - nutritional deficiency, such as vitamin B12 deficiencyVitamin B12 deficiencyVitamin B12 deficiency or hypocobalaminemia is a low blood level of vitamin B12, it can cause permanent damage to nervous tissue as a long term effect. Vitamin B12 was discovered from its relationship to the disease pernicious anemia, which is an autoimmune disease that destroys parietal cells in...
- other acquired metabolic disorders, including electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
disturbances such as hypocalcemia, hypernatremiaHypernatremiaHypernatremia or hypernatraemia is an electrolyte disturbance that is defined by an elevated sodium level in the blood. Hypernatremia is generally not caused by an excess of sodium, but rather by a relative deficit of free water in the body...
, hyponatremiaHyponatremiaHyponatremia is an electrolyte disturbance in which the sodium concentration in the serum is lower than normal. In the vast majority of cases, hyponatremia occurs as a result of excess body water diluting the serum sodium and is not due to sodium deficiency. Sodium is the dominant extracellular...
, hypokalemiaHypokalemiaHypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...
, hypomagnesemiaHypomagnesemiaHypomagnesemia is an electrolyte disturbance in which there is an abnormally low level of magnesium in the blood. Usually a serum level less than 0.7 mmol/L is used as reference. The prefix hypo- means low . The middle 'magnes' refers to magnesium...
, hypermagnesemiaHypermagnesemiaHypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood. Usually this results in excess of magnesium in the body....
, hypercalcemia, and hypophosphatemiaHypophosphatemiaHypophosphatemia is an electrolyte disturbance in which there is an abnormally low level of phosphate in the blood. The condition has many causes, but is most commonly seen when malnourished patients are given large amounts of carbohydrates, which creates a high phosphorus demand by cells,...
, but also hypoglycemiaHypoglycemiaHypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
, hypoxiaHypoxia (medical)Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
, and failure of the liverLiverThe liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
or kidneys - autoimmune and related disorders, such as systemic lupus erythematosusSystemic lupus erythematosusSystemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...
(lupus, SLE), sarcoidosisSarcoidosisSarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...
, Hashimoto's encephalopathyHashimoto's encephalopathyHashimoto's Encephalopathy is a very rare condition associated with Hashimoto's thyroiditis. It was first described in 1966. It is classified as a neuroendocrine disorder....
, and anti-NMDA-receptor encephalitis - poisoning, by therapeutic drugs (see below), recreational drugs (see below), and a range of plants, fungi, metals, organic compounds, and a few animal toxins
- some sleep disorders, including hallucinations in narcolepsyNarcolepsyNarcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...
(in which REM sleep intrudes into wakefulness)
Psychosis can even be caused by familiar ailments such as flu or mumps
Mumps
Mumps is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide...
.
Recreational drugs
Various psychoactive substances (both legal and illegal) have been implicated in causing, exacerbating, and/or precipitating psychotic states and/or disorders in users. This may be upon intoxication, for a more prolonged period after use, or upon withdrawal. Drugs that can induce psychotic symptoms include amphetamineAmphetamine
Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...
, caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
(which can worsen psychotic symptoms in schizophrenia and produce olfactory hallucinations at very high doses in normal volunteers), cannabis
Cannabis
Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
, cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
, desoxypipradrol
Desoxypipradrol
Desoxypipradrol, also known as 2-diphenylmethylpiperidine , acts as a norepinephrine-dopamine reuptake inhibitor developed by Ciba in the 1950s...
, dimethyltryptamine
Dimethyltryptamine
N,N-Dimethyltryptamine is a naturally occurring psychedelic compound of the tryptamine family. DMT is found in several plants, and also in trace amounts in humans and other mammals, where it is originally derived from the essential amino acid tryptophan, and ultimately produced by the enzyme INMT...
, alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
(ethanol), inhalants, gammahydroxybutyric acid (and its precursors gammabutyrolactone and 1,4-butanediol
1,4-Butanediol
1,4-Butanediol is the organic compound with the formula HOCH2CH2CH2CH2OH. This colorless viscous liquid is derived from butane by placement of alcohol groups at each end of the chain. It is one of four stable isomers of butanediol.-Synthesis:...
), ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
, LSD
LSD
Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synaesthesia, an...
, mephedrone and methcathinone
Methcathinone
Methcathinone , is a psychoactive stimulant, sometimes used as a recreational drug and considered addictive. It is usually snorted, but can be smoked, injected, or taken orally...
, mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....
and other phenethylamine hallucinogens, methamphetamine
Methamphetamine
Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...
, MDMA (very rarely), opiates such as heroin, phencyclidine
Phencyclidine
Phencyclidine , commonly initialized as PCP and known colloquially as angel dust, is a recreational dissociative drug...
, piperazine
Piperazine
Piperazine is an organic compound that consists of a six-membered ring containing two opposing nitrogen atoms. Piperazine exists as small alkaline deliquescent crystals with a saline taste....
-based drugs, psilocybin
Psilocybin
Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...
, and anabolic steroids at high doses.
Frequent users of cannabis
Cannabis
Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
have twice the likelihood of developing both psychosis and schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
. Older studies indicate that certain strains containing large proportions of tetrahydrocannabinol and low proportions of cannabidiol merely lowers the threshold for psychosis, and thus helps to trigger full-blown psychosis in some people. On the other hand, cannabis use has increased dramatically over the past few decades but declined in the last decade, whereas the rate of psychosis has not increased. This suggests cannabis generally only hastens the onset of psychosis in those who would otherwise only become psychotic at a later date.
Medication
Administration, or sometimes withdrawal, of a large number of medications may provoke psychotic symptoms. Drugs that can induce psychosis experimentally and/or in a significant proportion of patients include amphetamineAmphetamine
Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...
and other sympathomimetics, dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
agonists, ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
, corticosteroids (often with mood changes in addition), and some anticonvulsants such as vigabatrin
Vigabatrin
Vigabatrin is an antiepileptic drug that inhibits the catabolism of gamma-aminobutyric acid by irreversibly inhibiting GABA transaminase. It is an analog of GABA, but it is not a receptor agonist...
.
Pathophysiology
The first brain image of an individual with psychosis was completed as far back as 1935 using a technique called pneumoencephalographyPneumoencephalography
Pneumoencephalography is a medical procedure in which most of the cerebrospinal fluid is drained from around the brain and replaced with air, oxygen, or helium to allow the structure of the brain to show up more clearly on an X-ray image...
(a painful and now obsolete procedure where cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
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
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
picture).
The purpose of the brain is to collect information from the body (pain, hunger, etc.), and from the outside world, interpret it to a coherent world view, and produce a meaningful response. The information from the senses enter the brain in the primary sensory areas
Primary sensory areas
The primary sensory areas are the main cerebral areas that receive sensory information from thalamic nerve projections.Though some areas of the human brain that receive primary sensory information remain poorly defined, each of the five sensory modalities has been recognized to relate to specific...
. They process the information and send it to the secondary areas where the information is interpreted. Spontaneous activity in the primary sensory areas may produce hallucinations which are misinterpreted by the secondary areas as information from the real world.
For example, a PET
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
or fMRI scan of a person who claims to be hearing voices may show activation in the primary auditory cortex, or parts of the brain involved in the perception and understanding of speech.
Tertiary brain cortex collects the interpretations from the secondary cortexes and creates a coherent world view of it. A study investigating structural changes in the brains of people with psychosis showed there was significant grey matter
Grey matter
Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil , glial cells and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts...
reduction in the right medial temporal, lateral temporal
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
, and inferior frontal gyrus
Inferior frontal gyrus
The inferior frontal gyrus is a gyrus of the frontal lobe . It is labelled gyrus frontalis inferior, its Latin name...
, and in the cingulate cortex
Cingulate cortex
The cingulate cortex is a part of the brain situated in the medial aspect of the cortex. It includes the cortex of the cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus...
bilaterally of people before and after they became psychotic. Findings such as these have led to debate about whether psychosis itself causes excitotoxic brain damage
Excitotoxicity
Excitotoxicity is the pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters such as glutamate and similar substances. This occurs when receptors for the excitatory neurotransmitter glutamate such as the NMDA receptor and AMPA receptor are...
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.
Studies with sensory deprivation
Sensory deprivation
Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch,...
have shown that the brain is dependent on signals from the outer world to function properly. If the spontaneous activity in the brain is not counterbalanced with information from the senses, loss from reality and psychosis may occur after some hours. A similar phenomenon is paranoia
Paranoia
Paranoia [] is a thought process believed to be heavily influenced by anxiety or fear, often to the point of irrationality and delusion. Paranoid thinking typically includes persecutory beliefs, or beliefs of conspiracy concerning a perceived threat towards oneself...
in the elderly when poor eyesight, hearing and memory causes the person to be abnormally suspicious of the environment.
On the other hand, loss from reality may also occur if the spontaneous cortical activity is increased so that it is no longer counterbalanced with information from the senses. The 5-HT2A receptor
5-HT2A receptor
The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...
seems to be important for this, since psychedelic drugs which activate them produce hallucinations.
However, the main feature of psychosis is not hallucinations, but the inability to distinguish between internal and external stimuli. Close relatives to psychotic patients may hear voices, but since they are aware that they are unreal they can ignore them, so that the hallucinations do not affect their reality perception. Hence they are not considered to be psychotic.
Psychosis has been traditionally linked to the neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
. 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
Mesolimbic pathway
The mesolimbic pathway is one of the dopaminergic pathways in the brain. The pathway begins in the ventral tegmental area of the midbrain and connects to the limbic system via the nucleus accumbens, the amygdala, and the hippocampus as well as to the medial prefrontal cortex...
. The two major sources of evidence given to support this theory are that dopamine receptor D2
Dopamine receptor D2
Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene.- Function :This gene encodes the D2 subtype of the dopamine receptor. This G protein-coupled receptor inhibits adenylyl cyclase activity...
blocking drugs (i.e., antipsychotic
Antipsychotic
An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...
s) tend to reduce the intensity of psychotic symptoms, and that drugs which boost dopamine activity (such as amphetamines and cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
) can trigger psychosis in some people (see amphetamine psychosis
Amphetamine psychosis
Stimulant psychosis is a psychotic disorder that appears in some people who use stimulant drugs. Most commonly, stimulant psychosis occurs in drug abusers who take very large doses but, in rare cases, it can also present in patients taking therapeutic doses under medical supervision...
). 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
NMDA receptor
The NMDA receptor , a glutamate receptor, is the predominant molecular device for controlling synaptic plasticity and memory function....
. This theory is reinforced by the fact that dissociative NMDA receptor antagonists such as ketamine
Ketamine
Ketamine is a drug used in human and veterinary medicine. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist...
, PCP
Phencyclidine
Phencyclidine , commonly initialized as PCP and known colloquially as angel dust, is a recreational dissociative drug...
and dextromethorphan
Dextromethorphan
Dextromethorphan is an antitussive drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, and others, including generic labels. Dextromethorphan has also found other uses in medicine, ranging...
/dextrorphan
Dextrorphan
Dextrorphan is a psychoactive drug of the morphinan chemical class which acts as an antitussive or cough suppressant and dissociative hallucinogen. It is the dextro-stereoisomer of racemorphan, the levo-half being levorphanol. Dextrorphan is produced by O-demethylation of dextromethorphan by CYP2D6...
(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, including negative psychotic symptoms, more closely 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
Sleep deprivation
Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
, which can independently produce psychosis. New antipsychotic drugs which act on glutamate and its receptors are currently undergoing clinical trials.
The connection between dopamine and psychosis is generally believed to be complex. While dopamine receptor D2 suppresses adenylate cyclase
Adenylate cyclase
Adenylate cyclase is part of the G protein signalling cascade, which transmits chemical signals from outside the cell across the membrane to the inside of the cell ....
activity, the D1
Dopamine receptor D1
Dopamine receptor D1, also known as DRD1, is a protein that in humans is encoded by the DRD1 gene.- Function :This gene encodes the D1 subtype of the dopamine receptor. The D1 subtype is the most abundant dopamine receptor in the central nervous system. This G-protein-coupled receptor stimulates...
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, a process 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. 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
Ondansetron
Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic , often following chemotherapy. Its effects are thought to be on both peripheral and central nerves...
, a 5-HT3 receptor antagonist, in the treatment of levodopa
Levodopa
L-DOPA is a chemical that is made and used as part of the normal biology of some animals and plants. Some animals including humans make it via biosynthesis from the amino acid L-tyrosine. L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine , and epinephrine collectively...
psychosis in Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
patients.
Psychiatrist David Healy
David Healy (psychiatrist)
David Healy is an Irish psychiatrist who is currently a professor in Psychological Medicine at Cardiff University School of Medicine, Wales. He is also the director of North Wales School of Psychological Medicine. He became the centre of controversy concerning the influence of the pharmaceutical...
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.
It has been suggested that persons with bipolar disorder
Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
may have increased activity of the left hemisphere compared to the right hemisphere of the brain, while persons with schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
have increased activity in the right hemisphere.
Increased level of right hemisphere activation has also been found in people who have high levels of paranormal
Paranormal
Paranormal is a general term that designates experiences that lie outside "the range of normal experience or scientific explanation" or that indicates phenomena understood to be outside of science's current ability to explain or measure...
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 and others distressing.
Diagnosis
Diagnosing the presence and/or extent of psychosis may be distinguished from diagnosing the cause of psychosis.The presence of psychosis is typically diagnosed by clinical interview, incorporating mental state examination. Its extent may be established by formal rating scales. The Brief Psychiatric Rating Scale
Brief Psychiatric Rating Scale
The Brief Psychiatric Rating Scale is rating scale which a clinician or researcher may use to measure psychiatric symptoms such as depression, anxiety, hallucinations and unusual behaviour...
(BPRS) assesses the level of 18 symptom constructs of psychosis such as hostility
Hostility
Hostility is a form of angry internal rejection or denial in psychology. It is a part of personal construct psychology, developed by George Kelly...
, suspicion
Suspicion (emotion)
Suspicion is a cognition of mistrust in which a person doubts the honesty of another person or believes another person to be guilty of some type of wrongdoing or crime, but without sure proof. Suspicion can also be aroused in response to objects that negatively differ from an expected idea...
, hallucination
Hallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
, and grandiosity
Grandiosity
Grandiosity is chiefly associated with narcissistic personality disorder, but also commonly features in manic or hypomanic episodes of bipolar disorder....
. 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 provide 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).
Establishing the cause of psychosis requires clinical examination, and sometimes special investigations, to diagnose or exclude secondary causes of psychosis; if these are excluded, a primary psychiatric diagnosis can be established.
Treatment
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 antipsychoticAntipsychotic
An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...
medication (oral or intramuscular injection), and sometimes hospitalization
Inpatient care
Inpatient care is the care of patients whose condition requires admission to a hospital. Progress in modern medicine and the advent of comprehensive out-patient clinics ensure that patients are only admitted to a hospital when they are extremely ill or are have severe physical...
is needed. There is growing evidence that cognitive behavior therapy and family therapy
Family therapy
Family therapy, also referred to as couple and family therapy, family systems therapy, and family counseling, is a branch of psychotherapy that works with families and couples in intimate relationships to nurture change and development. It tends to view change in terms of the systems of...
can be effective in managing psychotic symptoms. When other treatments for psychosis are ineffective, electroconvulsive therapy
Electroconvulsive therapy
Electroconvulsive therapy , formerly known as electroshock, is a psychiatric treatment in which seizures are electrically induced in anesthetized patients for therapeutic effect. Its mode of action is unknown...
or ECT (also known as shock treatment) is sometimes applied to relieve the underlying symptoms of psychosis due to depression. There is also increasing research suggesting that animal-assisted therapy
Animal-Assisted Therapy
Animal-assisted therapy is a relatively new field of study, although the human-animal bond has existed for thousands of years. AAT is a type of therapy that involves animals as a form of treatment. The goal of AAT is to improve a patient’s social, emotional, or cognitive functioning...
can contribute to the improvement in general well-being of people with schizophrenia.
Early intervention
Early intervention in psychosisEarly intervention in psychosis
Early intervention in psychosis is a clinical approach to those experiencing symptoms of psychosis for the first time. It forms part of a new prevention paradigm for psychiatry and is leading to reform of mental health services, especially in the United Kingdom....
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
Critical period
This article is about a critical period in an organism's or person's development. See also America's Critical Period.In general, a critical period is a limited time in which an event can occur, usually to result in some kind of transformation...
, 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
Prodrome
In medicine, a prodrome is an early symptom that might indicate the start of a disease before specific symptoms occur. It is derived from the Greek word prodromos or precursor...
" or "at risk mental state
At risk mental state
At risk mental state is the term used to describe the clinical presentation of those considered at risk of developing psychosis or schizophrenia...
") suggests that such input can prevent or delay the onset of psychosis.
History
The word psychosis was first used by Ernst von Feuchtersleben in 1845 as an alternative to insanityInsanity
Insanity, craziness or madness is a spectrum of behaviors characterized by certain abnormal mental or behavioral patterns. Insanity may manifest as violations of societal norms, including becoming a danger to themselves and others, though not all such acts are considered insanity...
and mania
Mania
Mania, the presence of which is a criterion for certain psychiatric diagnoses, is a state of abnormally elevated or irritable mood, arousal, and/ or energy levels. In a sense, it is the opposite of depression...
and stems from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
ψύχωσις (psychosis), "a giving soul or life to, animating, quickening" and that from ψυχή (psyche), "soul" and the suffix -ωσις (-osis), in this case "abnormal condition".
The word was used to distinguish disorders which were thought to be disorders of the mind, as opposed to "neurosis
Neurosis
Neurosis is a class of functional mental disorders involving distress but neither delusions nor hallucinations, whereby behavior is not outside socially acceptable norms. It is also known as psychoneurosis or neurotic disorder, and thus those suffering from it are said to be neurotic...
", which was thought to stem from a disorder of the nervous system. The psychoses thus became the modern equivalent of the old notion of madness
Insanity
Insanity, craziness or madness is a spectrum of behaviors characterized by certain abnormal mental or behavioral patterns. Insanity may manifest as violations of societal norms, including becoming a danger to themselves and others, though not all such acts are considered insanity...
, and hence there was much debate on whether there was only one (unitary)
Unitary psychosis
Unitary psychosis refers to the 19th-century belief prevalent in German psychiatry until the era of Emil Kraepelin that all forms of psychosis were surface variations of a single underlying disease process...
or many forms of the new disease.
The division of the major psychoses into manic depressive illness (now called bipolar disorder
Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
) and dementia praecox (now called schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
) was made by Emil Kraepelin
Emil Kraepelin
Emil Kraepelin was a German psychiatrist. H.J. Eysenck's Encyclopedia of Psychology identifies him as the founder of modern scientific psychiatry, as well as of psychopharmacology and psychiatric genetics. Kraepelin believed the chief origin of psychiatric disease to be biological and genetic...
, who attempted to create a synthesis of the various mental disorders identified by 19th century psychiatrists
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...
, by grouping diseases together based on classification of common symptoms. Kraepelin used the term 'manic depressive insanity' to describe the whole spectrum of mood disorder
Mood disorder
Mood disorder is the term designating a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
s, in a far wider sense than it is usually used today. In Kraepelin's classification this would include 'unipolar' clinical depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
, as well as bipolar disorder and other mood disorders such as cyclothymia
Cyclothymia
Cyclothymia is a mood and mental disorder in the bipolar spectrum that causes both hypomanic and depressive episodes. It is defined medically within the bipolar spectrum and consists of recurrent disturbances between sudden hypomania and dysthymic episodes. The diagnosis of cyclothymic disorder is...
. 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
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
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
Counterculture
Counterculture is a sociological term used to describe the values and norms of behavior of a cultural group, or subculture, that run counter to those of the social mainstream of the day, the cultural equivalent of political opposition. Counterculture can also be described as a group whose behavior...
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. Arthur J. Deikman
Arthur J. Deikman
Arthur J. Deikman is a clinical professor of psychiatry at the University of California, San Francisco, and a member of the editorial board of the Journal of Humanistic Psychology and Human Givens...
suggested use of the term "mystical psychosis
Mystical psychosis
Mystical psychosis is a term coined by Arthur J. Deikman in the early 1970’s to characterize first-person accounts of psychotic experiences that are strikingly similar to reports of mystical experiences...
" to characterize first-person accounts of psychotic experiences that are similar to reports of mystical experiences. Thomas Szasz
Thomas Szasz
Thomas Stephen Szasz is a psychiatrist and academic. Since 1990 he has been Professor Emeritus of Psychiatry at the State University of New York Health Science Center in Syracuse, New York. He is a well-known social critic of the moral and scientific foundations of psychiatry, and of the social...
focused on the social implications of labeling
Labeling theory
Labeling theory is closely related to interactionist and social construction theories. Labeling theory was developed by sociologists during the 1960's. Howard Saul Becker's book entitled Outsiders was extremely influential in the development of this theory and its rise to popularity...
people as psychotic, a label he argues unjustly medicalises different views of reality so such unorthodox people can be controlled by society. Psychoanalysis
Psychoanalysis
Psychoanalysis is a psychological theory developed in the late 19th and early 20th centuries by Austrian neurologist Sigmund Freud. Psychoanalysis has expanded, been criticized and developed in different directions, mostly by some of Freud's former students, such as Alfred Adler and Carl Gustav...
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
Recovery model
The Recovery Model as it applies to mental health is an approach to mental disorder or substance dependence that emphasizes and supports each individual's potential for 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.
See also
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.Philip K. DickPhilip Kindred Dick was an American novelist, short story writer and essayist whose published work is almost entirely in the science fiction genre. Dick explored sociological, political and metaphysical themes in novels dominated by monopolistic corporations, authoritarian governments and altered...
(1981) VALISVALISVALIS is a 1981 science fiction novel by Philip K. Dick. The title is an acronym for Vast Active Living Intelligence System, Dick's gnostic vision of one aspect of God....
. 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.Kay Redfield JamisonKay Redfield Jamison is an American clinical psychologist and writer whose work has centered on bipolar disorder which she has suffered from since her early adulthood...
(1995) An Unquiet Mind: A Memoir of Moods and Madness. London: Picador.
ISBN 0-679-76330-9 - Schreber, Daniel PaulDaniel Paul SchreberDaniel Paul Schreber was a German judge who suffered from what was then diagnosed as dementia praecox. He described his second mental illness , making also a brief reference to the first illness in his book Memoirs of My Nervous Illness...
(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 ExpressThe Eden ExpressThe Eden Express: A Memoir of Insanity is a 1975 book by Mark Vonnegut, son of American writer Kurt Vonnegut, about Mark's experiences in the late 1960s and his major psychotic breakdown and recovery...
by Mark VonnegutMark VonnegutMark Vonnegut is an American pediatrician and memoirist. He is the son of the late writer Kurt Vonnegut, Jr. and his first wife, Jane Cox. He is also the brother of Edith and Nanette Vonnegut. He described himself in the preface to his 1975 book as "a hippie, son of a counterculture hero, B.A... - James Tilly MatthewsJames Tilly MatthewsJames Tilly Matthews was a London tea broker, originally from Wales, who was committed to the Bethlem psychiatric hospital in 1797, and is considered to be the first fully documented case of paranoid schizophrenia....
- Saks, Elyn R. (2007) The Center Cannot Hold—My Journey Through Madness. New York: Hyperion. ISBN 978-1-4013-0138-5