The Insanity Defense Reform Act of 1984, signed into law on October 12, 1984, was the first comprehensive Federal legislation governing the insanity defense and the disposition of individuals suffering from a mental disease or defect who are involved in the criminal justice system. The more significant provisions:
- significantly modified the standard for insanity previously applied in the Federal courts;
- placed the burden of proof on the defendant to establish the defense by clear and convincing evidence;
- limited the scope of expert testimony on ultimate legal issues;
- eliminated the defense of diminished capacity;
- created a special verdict of "not guilty only by reason of insanity," which triggers a commitment proceeding; and
- provided for Federal commitment of persons who become insane after having been found guilty or while serving a Federal prison sentence.