In psychopathology, psychosis is a condition in which one is unable to distinguish, in one's experience of life, between what is and is not real. Examples of psychotic symptoms are delusions, hallucinations, and disorganized or incoherent thoughts or speech. Psychosis is a description of a person's state or symptoms, rather than a particular mental illness, and it is not related to psychopathy (a personality construct characterized by impaired empathy and remorse, along with bold, disinhibited, and egocentric traits).
Common causes of chronic (i.e. ongoing or repeating) psychosis include schizophrenia or schizoaffective disorder, bipolar disorder, and brain damage (usually as a result of alcoholism). Acute (temporary) psychosis can also be caused by severe distress, sleep deprivation, sensory deprivation, some medications, and drug use (including alcohol, cannabis, hallucinogens, and stimulants). Acute psychosis is termed primary if it results from a psychiatric condition and secondary if it is caused by another medical condition or drugs. The diagnosis of a mental-health condition requires excluding other potential causes. Tests can be done to check whether psychosis is caused by central nervous system diseases, toxins, or other health problems.