Insanity
Insanity, in law, a general term for mental unsoundness and incompetence. Insanity in legal language signifies that a person is unable to manage himself or his affairs, or is in need of care or control, or is not to be held legally responsible for his actions. In law, insanity includes both idiocy (the state of one who has been without reason since birth) and lunacy (the state of one who formerly had reason but has lost it). The legal concepts and terms differ from those used in psychology and medicine.
Insanity becomes an issue in three kinds of cases. (1) A person may be unable to control himself or manage his own affairs; (2) he may be dangerous to himself or society; (3) he may enter a plea of insanity in answer to a criminal charge.
In Civil CasesIn civil insanity a court may appoint a guardian to manage the affairs of a mentally incompetent person. If a person is unable to control himself or if he is criminally insane (dangerous to himself or to others) a court may commit him to an institution on the request of close relatives or public authorities.
In Criminal CasesIn criminal law the traditional mark of insanity is a person's inability to distinguish between right and wrong and act accordingly. In many states, the accused is examined before trial and, if found insane, committed to a mental hospital for treatment. In trials in some states, a person can be found “not guilty by reason of insanity.” Such a verdict usually results in commitment to a mental hospital, from which release may be gained if the person is later declared sane. Some states allow a verdict of “guilty but insane”; the person is given a prison sentence, but first receives treatment in a mental hospital.
Sometimes in criminal trials the defense attorney tries to show “temporary insanity.” He admits his client is normally sane but for some reason was really insane at the time of the alleged crime. A similar plea is “irresistible impulse,” which contends that at the time of the act the defendant had lost all power to refrain.