1. A defendant is not criminally responsible by reason of insanity if, at the time of the criminal conduct, as a result of mental disease or defect, the defendant lacked substantial capacity to appreciate the wrongfulness of the criminal conduct.
[ 2005, c. 263, §5 (AMD) .]
2. As used in this section, "mental disease or defect" means only those severely abnormal mental conditions that grossly and demonstrably impair a person's perception or understanding of reality. An abnormality manifested only by repeated criminal conduct or excessive use of alcohol, drugs or similar substances, in and of itself, does not constitute a mental disease or defect.
[ 1985, c. 796, §5 (AMD) .]
3. Lack of criminal responsibility by reason of insanity is an affirmative defense.
[ 2005, c. 263, §6 (NEW) .]
1981, c. 324, §14 (NEW). 1985, c. 796, §5 (AMD). 2005, c. 263, §§5,6 (AMD).