Severe forms of the mental illness characterized by a loss of reality testing, such as hallucinations and delusions.

Those mental diagnoses that indicate lack of mental function pertaining to either or both a psychiatrically diagnosed and legally recognized inability to fully and normally function and usually indicating the presence of one or a combination of the three functional psychoses: schizophrenia (symptoms: delusions or hallucinations, disorganized speech, grossly disorganized behavior); manic-depressive psychosis (symptoms: episodes of abnormally and persistently elevated moods or euphoria that may shift rapidly to anger or depression); paranoia or paranoid personality disorder (symptoms: general distrust and suspiciousness of others and their motives marked by delusional or hallucinatory episodes; preoccupation with unjustified doubts; interpersonal aloofness and combativeness).

Plural for psychosis.