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Insanity Notes

Law Notes > LAWS201 Criminal Law Notes

This is an extract of our Insanity document, which we sell as part of our LAWS201 Criminal Law Notes collection written by the top tier of Univerity Of Otago students.

The following is a more accessble plain text extract of the PDF sample above, taken from our LAWS201 Criminal Law Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Insanity Can the defendant show on the balance of probabilities that he was labouring under natural imbecility/a disease of the mind?

Two steps:



Did the defendant for this reason not

Know subjectively that the act was morally wrong (on his own subjective moral standard Dixon, MacMillan

Understand the nature and quality of the act No

No insanity defence

Yes, insanity defence

Section 23 Insanity (1) Everyone shall be presumed to be sane at the time of doing or omitting any act until the contrary is proved (2) No person shall be convicted of an offence by reason of an act done or omitted by him when labouring under natural imbecility or disease of the mind to such an extent as to render him incapable (a) Of understanding the nature and quality of the act or omission; or (b) Of knowing that the act or omission was morally wrong, having regard to the commonly accepted standards of right and wrong (3) Insanity before or after the time when he did or omitted the act, and insane delusions, though only partial, may be evidence that the offender was, at the time when he did or omitted the act, in such a condition of mind as to render him irresponsible for the act or omission (4) The fact that by virtue of this section any person has not been or is not liable to be convicted of an offence shall not affect the question whether any other person who is alleged to be a party to that offence is guilty of that offence.

Based on M'Naghten Rules M was a normal guy, became associated with radical left wing politics, formed the view that the Tories were out to get him. To make himself safe, he decided to kill the Tory PM. Bought two pistols, got close to PM, but killed a civil servant (Drummond) by mistake. (1) "labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing, or if he did, that he did not know he was doing what was wrong." - Lord CJ someone (2) "Where one labour under partial delusions only and is not in other respects insane, and commits an offence due to that fact, he must be considered in the same situation as to responsibility as if the facts with respect to which the delusion exists were real." Strict liability Insanity is an excuse that goes to the mens rea of a defence, so could be used in NZ as a defence to a strict liability offence, as it would discharge the presumption of mens rea. Useful in NZ, not England, where there is no strict liability: just absolute - Director of Public Prosecutions v H.

Natural Imbecility "Subnormality" or "mental retardation". Needn't be permanent, must be durable. May be congenital or develop later in life. Imperfect condition from congenital defect or natural decay, not disease. - R v Cooper (Canadian Constitutional Court) Test is legal, not medical.
* R v Mrzljak (2004)
# Mildly intellectually impaired, spoke little English, accused of raping another intellectually impaired woman
# Felt that the degree of his impairment was such as to make it more difficult for him to pick up cues from women that there was no consent.

Disease of the Mind Medical witnesses are permitted to give their opinions, but medical classification is not final: this is a legal test. Mental derangement in the widest sense (Cottle) but more than a common psychological disturbance (e.g. Anger) - Porter. A condition may be a disease of the mind without damaging the brain or any physical organ, as long as it affects mental facul ties. May be permanent or temporary - Kemp.

Personality disorders
* Simester & Brookbanks: "it is ultimately for the courts to determine whether it qualifies as mental disease...
* Adams: 'there would seem to be no reason in principle to conclude that a diagnosed severe personality disorder could never constitute or contribute to a "disease of the mind" for the purposes of s 23, where its effect was to render the accused incapable of knowing what he or she was doing, or that the act was morally wrong.'
# But if the actor knew what they were doing was wrong, but just didn't care, no defence. Lack of empathy isn't insanity. Dissociative identity disorder (DID) Disease of mind - R v Hamblyn. But alter egos were not insane (did understand morality, nature and quality of acts), and to find otherwise would give a complete defence in these

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