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n. in a criminal prosecution, a defense by the accused that he/she was briefly insane at the time the crime was committed and therefore was incapable of knowing the nature of his/her alleged criminal act. Temporary insanity is claimed as a defense whether or not the accused is mentally stable at the time of trial. One difficulty with a temporary insanity defense is the problem of proof, since any examination by psychiatrists had to be after the fact, so the only evidence must be the conduct of the accused immediately before or after the crime. It is similar to the defenses of "diminished capacity" to understand one's own actions, the so-called "twinky defense," the "abuse excuse," "heat of passion," and other claims of mental disturbance which raise the issue of criminal intent based on modern psychiatry and/or sociology. However, mental derangement at the time of an abrupt crime, such as a sudden attack or crime of passion, can be a valid defense, or at least show lack of premeditation to reduce the degree of the crime. (See: crime, insanity, intent, defense, diminished capacity)