insanity

• full defence - not guilty by reason of insanity
• burden of proof on defence to prove defendant was suffering from insanity based on the balance of probabilities
• rules of insanity set out in (mcnaghten)
• 1. must be a defect of reason
• d's powers of reasoning must be impaired
• must be more than absentmindedness (clarke)
• it can be permanent or temporary (sullivan)
• 2. caused by disease of the mind
• legal term not a medical term
• can be a physical or mental disease
• includes sleepwalking (burgess)
• hardening of arteries (kemp)
• epilepsy (sullivan)
• diabetes caused by internal factor due to not taking insulin (hennessy)
• 3. d must not know nature and quality of their act (oye)
• if they did, must know it is legally wrong (windle)
• if suffering from delusions but know nature and quality of act defence will fail (johnson)
• if d is voluntary intoxicated it is an external factor, cannot rely on defence (coley)