Insanity

Insanity, craziness or madness is a spectrum of behaviors characterized by certain abnormal mental or behavioral patterns. Insanity may manifest as violations of societal norms, including a person becoming a danger to themselves or others, though not all such acts are considered insanity. In modern usage insanity is most commonly encountered as an informal unscientific term denoting mental instability, or in the narrow legal context of the insanity defense. In the medical profession the term is now avoided in favor of diagnoses of specific mental disorders; the presence of delusions or hallucinations is broadly referred to as psychosis. When discussing mental illness in general terms, "psychopathology" is considered a preferred descriptor.

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. Another Latin phrase related to our current concept of sanity 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.

A more informal use of the term insanity is to denote something considered highly unique, passionate or extreme, including in a positive sense. A notable example has been the use of the phrase 'insanely great' in the launch of the Apple Macintosh, subsequently also used to describe one of its developers. The term may also be used as an attempt to discredit or criticise particular ideas, beliefs, principals, desires, personal feelings, attitudes, or their proponents, such as in politics and religion.