Also known as: NGRI · insanity defense · insanity plea
Written by attorneys · grounded in primary & secondary sources — see below
A criminal verdict or plea finding the defendant not guilty because a mental disease or defect prevented the defendant from knowing the wrongfulness of the conduct or from conforming the conduct to the requirements of law. The verdict typically leads to involuntary commitment to a mental institution rather than outright release.
Natalie Norris was charged with assault after stabbing a coworker. She received Miranda warnings and remained silent during questioning. At trial she raised an insanity defense supported by psychiatric testimony. The court found her not guilty by reason of insanity and the prosecutor was barred from using her post-warning silence to suggest the defense was fabricated.
Nolan Nunez was indicted for arson. His counsel intended to assert an insanity defense but filed the required written notice only after the pretrial motion deadline had passed. The government moved to preclude the defense. After the court allowed late notice for good cause, the jury returned a verdict of not guilty by reason of insanity.
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Nyah Ndlovu was charged with burglary after entering a neighbor's home and removing valuables. She had a documented history of schizophrenia with delusions that the neighbor was storing government surveillance devices inside the residence. Under the Durham test the jury found that the offense was the product of her mental disease and returned a verdict of not guilty by reason of insanity.
Nicholas Nunez faced misdemeanor charges and wished to plead guilty to avoid commitment. The court refused the plea after a psychiatric report indicated possible insanity at the time of the offense. Nunez was later tried, found not guilty by reason of insanity, and committed despite his preference for a criminal conviction.
Noah Nakamura was charged with murder and raised an insanity defense. He made a preliminary showing that his mental condition would be central to the defense but lacked funds to retain a psychiatrist. The court ordered the state to provide access to a psychiatric expert. With that assistance Nakamura was found not guilty by reason of insanity.
Noelle North was charged with homicide in a high-profile case. Extensive media coverage detailed the facts before trial. She entered a plea of not guilty by reason of insanity. The court considered the publicity when evaluating motions for change of venue but allowed the insanity defense to proceed, resulting in an NGRI verdict.
The defendant is typically committed to a mental institution rather than released. Commitment continues until the defendant is no longer dangerous or has recovered sufficiently to be released under applicable standards.
Yes. Under federal rules a defendant must file written notice of intent to assert an insanity defense within the time for pretrial motions or at a later time set by the court. Failure to provide timely notice bars reliance on the defense absent good cause.
No. The prosecution may not introduce evidence of post-Miranda silence to rebut or counter an insanity defense because such use violates the implicit assurance that silence carries no penalty.
No. While virtually every state recognizes some form of the insanity defense, the federal constitution probably does not require states to provide insanity as a complete defense to criminal liability.
…was ratified. Commonwealth v. York , 50 Mass. 93 (1845).[^maj-8] In 1895 the common-law view was abandoned with respect to the insanity defense in federal prosecutions. Davis v. United States , 160 U. S. 469 (1895). This ruling had wide impact on the practice in the federal courts with respect to the burden of proving various…