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M'Naghten Rules

Definition

The 1843 English House of Lords formulation providing that a defendant is not criminally responsible if, at the time of the offence, by reason of disease of the mind, they did not know the nature and quality of their act, or did not know that it was wrong.

Related terms

Appreciation vs Knowledge
The MPC and Canadian Criminal Code use 'appreciate' rather than 'know,' requiring a deeper, emotionally integrated understanding of the nature or wrongfulness...
BNS § 22
India's insanity defence provision in the Bharatiya Nyaya Sanhita 2023, replacing IPC § 84: an act is not an offence if done...
Durham Rule
The 1954 US Court of Appeals (DC Circuit) product test: an accused is not criminally responsible if the unlawful act was the...
Guilty but Mentally Ill (GBMI)
A US verdict alternative introduced in some states from 1975: the defendant is found guilty (and sentenced) but is entitled to psychiatric...
Hari Singh Gond (2008)
Indian Supreme Court ruling setting out the four elements for establishing the IPC § 84 (now BNS § 22) defence: mental illness...
IDRA 1984
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MPC § 4.01 Substantial-Capacity Test
The American Law Institute's 1962 insanity formulation: a person lacks criminal responsibility if, as a result of mental disease or defect, they...

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