Insanity Knowledge Summary

• Definition:

  M'Naghten -a person is legally insane if they suffer a defect a reason caused by a disease of the mind so that they do not know the nature and quality of their act or that it was wrong in law.
• 1. A defect of reason - d's ability to make sensible and logical choices (their powers of reasoning) is impaired (limited).

  • R v Clarke - there must be some actual deprivation of the powers of reasoning, not just absent mindedness, confusion or simply failing to use their powers of reasoning.
• 2. A disease of the mind - in R v Bratty, Lord Denning defined a disease of the mind as 'any mental disorder which has manifested itself in violence and is prone to recur.'

  • A disease of the mind is a legal rather than a medical definition and means a malfunctioning of the mind (must have an effect on the brain) arising from an internal cause.
  • Physical (Kemp; arteriosclerosis) or mental conditions can amount to a disease of the mind and it can be permanent, temporary (transient), curable or incurable.
• • Sleep-walking: R v Burgess, epilepsy R v Sullivan
  • Diabetes: internal cause if hyperglycemia (high blood sugar); R v Hennessey who did not take his insulin. External cause if hypoglycemia (low blood sugar); R v Quick
• 3. The defect or a reason must be such that the

  • D did not know the nature and quality of what he was doing in terms of understanding the act he has done (R v Codere/R v Oye)
  • D did not know the act was wrong in law, R v Windle (killed his wife and said 'i supposed they will hang me for this')
• 4. Outcome: If the defence of insanity is established, the Special Verdict of Not Guilty by reason of insanity is given.

  • The Criminal Procedure (insanity & Unfitness to Plead) Act 1991 introduces various sentencing options:

  1. Hospital Treatment Order
  2. Supervision Order
  3. Absolute Discharge
  4. Murder = an indefinite hospital order must be imposed.

  1,2,3 - available to all offences but murder