Insanity cases

R v Kemp

Any condition that affects the mind can be a disease of the mind (eg diabetes)

M'naghten case

Insanity requires proof of a defect of reason, disease of the mind and D must not know the nature and quality of their act or that the act was wrong

R v Clarke

Ability to reason must be defective, not merely unused

R v Burgess

Insanity caused by an internal factor can be prone to reoccur and transient (for a short time.)

R v Hennessy

Lack of insulin meant internal diabetes was cause of defect of reason - insane automatism

R v Quick

Lack of food after insulin meant external diabetes was the cause of defect of reason - sane automatism

R v Windle

Saying "they'll hang me for this" showed he knew his actions were legally wrong

Insanity Checklist

- Defect of reason

- Disease of the mind

- Did not know nature and quality of act or did not know act was wrong

What type of defence is insanity?

General defence with a special verdict - ‘not guilty by reason of insanity’