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

Norm (sociology)

Social norms are the accepted behaviors within a society or group. This sociological and social psychological term has been defined as "the rules that a group uses for appropriate and inappropriate values, beliefs, attitudes and behaviors. These rules may be explicit or implicit...

, including becoming a danger to themselves and 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.