Define: Not Guilty By Reason Of Insanity

“Not guilty by reason of insanity” is a legal defence that can be used in criminal cases where the defendant argues that they should not be held criminally responsible for their actions because they were mentally ill or legally insane at the time of the offence. This defence asserts that the defendant lacked the mental capacity to understand the nature or consequences of their actions, or to conform their behaviour to the requirements of the law. If successful, the defendant is found not guilty by reason of insanity (NGRI), and instead of being convicted and punished, they may be committed to a psychiatric facility for treatment until they are deemed no longer a danger to themselves or others. The standards and procedures for the NGRI defence vary by jurisdiction, and it is typically subject to rigorous scrutiny by the court, involving expert testimony and evaluations of the defendant’s mental state at the time of the offence. The NGRI defence is relatively rare and is invoked in cases where there is substantial evidence of severe mental illness or impairment affecting the defendant’s ability to form criminal intent.

This site contains general legal information but does not constitute professional legal advice for your particular situation. Persuing this glossary does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

This glossary post was last updated: 29th March 2024.