For centuries, the insanity defense has been one of the most hotly debated issues in
criminal law. Nonetheless, scientific research shows the insanity defense is rarely used
and rarely successful. Furthermore, few defendants who plead insanity have been
charged with murder, and defendants found insane pose less of a danger to society than
defendants found guilty. Legislatures and courts have created five modern tests of
insanity, several variants of these tests, and enacted several other reforms to improve
insanity verdicts. However, scientific research shows different insanity tests do not affect
insanity verdicts, and the other insanity reforms are also ineffective. Instead of improving
insanity law, legislative and judicial reforms have created an irrational, illogical, unjust,
and immoral insanity law that is not in the best interest of society or defendants with
psychological disorders. This Article uses scientific research to explain why the public,
legislators, and judges generally have erroneous attitudes and beliefs about the insanity
defense and people with psychological disorders. It also uses scientific research to
explain why insanity law is irrational, illogical, unjust, and immoral. Lastly, the Article
delineates what legislatures, courts, and mental health organizations need to do to
improve insanity law.