Insanity

• Insanity 


  • General defence- all crimes
  • Complete defence
• Common law 


  The M'Naghten Rules (1843)

  "Was 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 know it, that he did not know what he was doing was wrong"
• Defect of reason 


  Must be an internal factor (disease of the mind) that causes the defendant to be totally deprived of the power of reasoning.

  R v Clarke- must be totally deprive of the power of reasoning.
• From "disease of the mind"

  • General mental illness
  • R v Hennessey- hypoglycaemia caused by diabetes
  • R v Kemp- Restriction of blood to the brain
  • R v Sullivan- Epilepsy
  • R v Quick- despite having diabetes, his actions were due to drugs instead so defence not allowed.
• "Not know the "nature and quality" of his act"

  D must be totally unaware of his actions- unconsciousness or blackout or state of consciousness that they have no realisation what is going on

  R v Windle- Had a history of mental health issues and murdered his wife, however he said "i shall be hung for this"- so understood that his actions were wrong

  R v Johnson- D knew his actions were legally wrong but not morally wrong, Court of Appeal said that the test where to determine if D knew their actions were legally wrong
• However,

  If this defence is successful, it may not mean that D is set free but instead sent to a mental hospital (Mental Health Act 1983)