image:The Rake's Progress 8.jpg Traditionally, insanity or madness is the behaviour whereby a person flouts societal norms and may become a danger to himself and others. Greek tragedies and Shakespeare often refer to madness in this sense. Psychologically, it is a general, popular and legal term defining behaviour influenced by mental instability. In modern usage, it is most commonly encountered as an informal, unscientific term, or in the narrow legal context of the insanity defense. In the medical profession the term is now avoided in favour of more specific diagnoses of mental illness such as schizophrenia and other psychotic disorders. When discussing mental illness in general terms, "psychopathology" is also considered a preferred descriptor.An interview with Dr. Joseph Merlino, David Shankbone, Wikinews, October 5, 2007.

Linguistic roots

In English, the word "sane" derives from the Latin adjective sanus meaning healthy. The phrase "mens sana in corpore sano" is often translated to mean a "healthy mind in a healthy body". From this perspective, insanity can be considered as poor health of the mind, not necessarily of the brain as an organ (although that can affect mental health), but rather refers to defective function of mental processes such as reasoning. A Latin phrase for "sane" is "compos mentis" (lit. "of composed mind"), and a euphemistic term for insanity is "non compos mentis". In law, mens rea means having had criminal intent, or a guilty mind, when the act (actus reus) was committed.

In medicine

Insanity is no longer considered a medical diagnosis but is a legal term in the United States, stemming from its original use in common law. The disorders formerly encompassed by the term covered a wide range of mental disorders now diagnosed as organic brain syndromes, schizophrenia, bipolar disorder and other psychotic disorders.

Historical treatment

During the 18th century, the French and English introduced humane treatment of the clinically insane, though the criteria for diagnosis and placement in an asylum were considerably looser than today, often including such conditions as speech impediments and epilepsy.

Europe's oldest asylum is The Bethlem Royal Hospital of London, also known as Bedlam, which began admitting the mentally ill in 1403. The first American asylum was built in Williamsburg, Virginia, circa 1773. Before the 19th century these hospitals were used to isolate the mentally ill or the socially ostracized from society rather than cure them or maintain their health. Pictures from this era portrayed patients bound with rope or chains, often to beds or walls, or restrained in straitjackets.