A set of rules, established in English law in Regina v. McNaghten (1843) and followed in many jurisdictions throughout the world, according to which legal proof of insanity, and thus lack of criminal responsibility, requires evidence that the accused either did not know what he or she was doing or was incapable of understanding that what he or she was doing was wrong. Also spelt McNaughten rules or M'Naghten rules. See also mens rea. [Established by the House of Lords following the case of R v. McNaghten (1843) in which the defendant, Daniel McNaghten, shot and killed the private secretary of the British Prime Minister Sir Robert Peel but was found to have been of unsound mind at the time]
Subjects: Law — Psychology.