A mental illness involving emotional disturbances that prevent realistic adjustment to environment. Neurasthenia, hysteria, compulsion phenomena, hypochondria, melancholia, psychopathic inferiority are forms of psychosis. A psychosis is more severe than a neurosis that permits at least some adjustment to reality. Symptoms of psychosis may include hallucinations, severe deviations of mood, absent or inappropriate emotional response, and severe distortion of judgment. Organic psychoses are caused by structural damage of the brain; functional psychoses show no observable organic damage.
Moral imputability is reduced or removed to the extent that psychopathic ideas and fancies so take possession of a person's mind that he or she cannot at all or only with great difficulty give attention to other considerations. Consequently, depending on the degree of mental illness, freedom of choice is either altogether impeded or at least gravely impaired. In individual cases it is very difficult to determine to what extent freedom of choice and hence responsibility are nullified. In most instances this must be left to the judgment of God. (Etym. Greek psyche, soul + osis, process, abnormal condition.)