You asked what the legal standard is for acquitting a defendant of criminal charges based on mental illness.

Under Connecticut law, criminal insanity is an affirmative defense. The defendant must prove that it is more likely than not that, at the time he committed the act, he lacked substantial capacity as a result of a mental disease or defect to appreciate the wrongfulness of his conduct or control it within the requirements of the law (CGS § 53a-13(a)). The insanity defense cannot be used by people whose criminal activity resulted from voluntary use of unprescribed intoxicants or compulsive gambling, or when an abnormality is demonstrated only by repeated criminal or antisocial conduct (CGS §§ 53a-13(b) and (c)).

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