Serious mental derangement characterized by defective or lost contact with reality.
The primary psychoses are schizophrenia and the delusional disorders (e.g., megalomania), but extreme cases of depression and bipolar disorder , substance-induced delirium , and certain varieties of dementia are also understood to share important features with the psychoses. The major symptoms, aside from delusions and hallucination s, are disorganized speech and behaviour and, often, mood disturbances. Treatment usually consists of medication and counseling in an institutional setting. Compare neurosis .