Insanity Defense

A criminal defendant who is found to have been legally insane when a crime was committed may be entitled to a not-guilty verdict, or may receive less severe punishment. Different definitions and tests for legal insanity exist, often depending on the type of crime and where (in what state) it was committed. Below you will find basic information and legal issues related to the insanity defense.

Background of the Insanity Defense

Legal Insanity: Current Trends

• Current Application of the Insanity Defense - Discusses how courts currently apply the insanity defense.
• Status of the Insanity Defense - Recent events have forced a reexamination of the insanity defense.

The Insanity Defense Among the States

Defining Legal Insanity as a Defense:

• The "M'Naghten Rule" - Describes the first standard for the insanity defense. The M'Naghten Rule is still used, in some form, by many U.S. jurisdictions.
• The "Irresistible Impulse" Test - This test was developed in response to criticisms of the M'Naughten Rule.
• The "Durham Rule" - This rule attempted to simplify the M'Naughten and Irresistible Impulse tests.
• The "Model Penal Code" Test for Legal Insanity - This broad rule incorporates aspects of all three of the preceding tests.