Sec. 53a-13
The lack of capacity due to mental disease or defect as affirmative defense.
(a) In any prosecution for an offense, it shall be an affirmative defense that the defendant, at the time he committed the proscribed act or acts, lacked substantial capacity, as a result of mental disease or defect, either to appreciate the wrongfulness of his conduct or to control his conduct within the requirements of the law .
(b) It shall not be a defense under this section if such mental disease or defect was approximately caused by the voluntary ingestion, inhalation or injection of intoxicating liquor or any drug was prescribed for the defendant by a prescreening practitioner, as defined in subdivision (22) of section 20-571, and was used in accordance with the directions of such prescription.
(c) As used in this section, the terms mental disease or defect do not include, (1) abnormality manifested only by repeated criminal or otherwise antisocial conduct or (2) pathological or compulsive gambling.
“The Supreme Court in Connecticut instructed the jury to consider “wrongfulness” as a test of insanity in the case State v. Wilson, 242 Conn. 605 (1997). The defendant must prove that at the time he/she committed the offense he misperceived reality due to a mental disease or defect and, in acting on the basis of the miss understanding, he did not have the substantial capacity to appreciate that his actions were contrary to societal morality, even though he may have been aware that the conduct in question was criminal. . The defendant must hold a sincere belief that society would condone his actions under the circumstances as he honestly perceived them. The court state that a defendant should not be adjudged legally insane simply because he elected to follow his own personal moral code as a result of mental disease.” (Reinhart)
“The court rejected a personal test for “wrongfulness” because such a test would excuse someone from criminal responsibility solely because in his own conscience his act was not morally wrong. The court state that its test balances societal morality and the concepts of moral justification.” (Reinhart)