The term "double insanity" is often used to describe a level of extreme madness, irrationality or craziness that is doubled or intensified. Some common synonyms for "double insanity" include "twin madness", "dual lunacy", "doubled delirium", "twofold insanity", "dual psychosis", "double derangement" and "duplicated mania". These terms are often used interchangeably to describe a state of great mental disturbance or instability. Whether we use "double insanity" or any of the synonyms mentioned, it is safe to say that it describes a level of madness that is beyond the normal range of human behavior and requires professional attention and care.