Psychosis

Psychosis (from the Ancient Greek ψυχή "psyche", for mind/soul, and -ωσις "-osis", for abnormal condition or derangement) refers to an abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "alternative or unusual conception of what is referred to as 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.

The term psychosis is very broad and can mean anything from relatively normal aberrant experiences through to the complex and catatonic expressions of schizophrenia and bipolar type 1 disorder. Moreover a wide variety of central nervous system diseases, from both external poisons and internal physiologic illness, can produce symptoms of psychosis. This led many professionals to say that psychosis is not specific enough as a diagnostic term. Despite this, "psychosis" is generally given to noticeable deficits in normal behavior (negative signs) and more commonly to diverse types of hallucinations or delusional beliefs (positive signs).

An excess in dopaminergic, and a deficit in glutamate(specifically NMDA) signalling correspond to positive and negative symptoms respectively. The NMDA antagonist MK-801 is used in animal models of schizophrenia, while paranoid and persecutory delusions are typical of methamphetamine users. In those with an organic psychosis, a complex cluster of genetic and environmental factors are involved in the creation of the endogenous imbalance of neurotransmitters observed in those with psychosis.

People experiencing psychosis 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.