"insanity [L. insanitas, insanity]. A severe mental disorder such as a psychosis. A general term for mental disorder or psychosis, now obsolete except as a legal term. In legal medicine, the state or mental condition characterized by inability to distinguish between right and wrong, possession of delusions or hallucinations that prevent individuals from looking after their own affairs with ordinary prudence or that render them a menace to others, or actions resulting from impulses of such intensity that they cannot be resisted.

During lucid intervals, an insane person may enter into a legal contract, marriage, business, or buying and selling, providing all the time he or she is capabale of entering into such matters with an understanding of all that is implied. The mental capacity at the time determines the validity of such acts and not the condidtion before or after. SEE: neurosis, psychosis."

Taber's Cyclopedic Medical Dictionary, Edition 16, copyright 1940-1989 by F.A. Davis Company