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A2 Criminal Law Defences Insanity

Resource summary

1 The rules on insanity are based on the M'Naghten Rules.
1.1 M'NAGHTEN - D thought he was being prosecuted by the Tories and tried to kill a member of the Government. Because of his mental state he was found not guilty of murder.
1.1.1 This lead to the House of Lords creating the definition of insanity. DEFINITION: "D must have such a defect of reason, from a disease of the mind which impairs his ability to understand the nature and quality of the act he was doing or not know what he was doing was wrong.
2 There are 3 elements that need to be proved.
2.1 1. Defect of reason.
2.1.1 D's power of reasoning must be impaired. If D is capable of reasoning but fails to use his powers, then this is not a defect of reason.
2.1.2 CLARKE - D took coffee and other items from the supermarket and put them in her bag. She claimed she forgot she had taken them from the shelves. It was held that absent mindedness is not a defect of reason and that insanity cannot be used as a defence.
2.2 2. Disease of the mind.
2.2.1 The defect of reason must be due to a disease of the mind. This is a legal term not a medical one. Disease of the mind can be mental or physical. KEMP - D had hardened arteries which caused problems with the blood supply in the brain causing temporary loss of consciousness. D attacked his wife during an unconscious episode, with a hammer. He was found not guilty by reason of insanity. SULLIVAN - House of Lords looked at whether epilepsy came within the rules of insanity. D was allowed the defence as it was held that it did not matter if the impairment was permanent or transient as long as it existed at the time of the act. HENNESSY - D a diabetic didn't take his insulin and had high blood sugar levels. During this time he stole a car while being disqualified from driving. D was allowed the defence of insanity as high blood sugar levels due to the diabetes was affecting his mind . BURGESS - In this case it was held that in some instances sleep-walking was within the legal definition of insanity. D attacked his girlfriend in his sleep and there was no evidence of any external cause for the sleep-walking. D was found not guilty by reason of insanity. External factors - if D is in a state where he is unaware of his conduct due to an external cause the defence of insanity is not available. QUICK - D was a diabetic who had taken his insulin but not eaten enough causing low blood sugar levels, which affects the brain. D assaulted a person but it was held that this condition did not come within the definition of insanity and it was caused by an external matter (the insulin).
2.3 3. Causing D to be unaware of the nature and quality of his act.
2.3.1 There are two ways in which D may not know the nature and quality of the act; because he is in a state of unconsciousness or if he is conscious, but due to his mental condition, does not know what he is doing is legally wrong. WINDLE - D's wife spoke of suicide so D killed her by giving her 100 aspirins. He gave himself up to the police and said "I suppose they will hang me for this." He was suffering from a mental illness but his words showed he was aware that what he had does was legally wrong so could not use the defence of insanity and was convicted of murder. JOHNSON - D, a schizophrenic, stabbed his neighbour. The courts followed the case of WINDLE and held that it didn't matter if D didn't know what he was doing was morally wrong because he was aware it was legally wrong. Therefore, D couldn't use the defence of insanity.
3 The burden of proof of insanity is on the defence, on a balance of probabilities.
3.1 If the defendant can use the defence of insanity the verdict will be "not guilty by reason of insanity."
3.1.1 Insanity is not a defence to strict liabilities but to all offences where mens rea is required. Up until 1991 the judge had to send the defendant to a mental hospital if found not guilty by reason of insanity. This was clearly not suitable for all cases such as cases of diabetes, epilepsy, etc. Therefore, the judge can now impose a hospital order, supervision order or an absolute discharge.
4 A02
4.1 The definition of insanity is outdated as it was set out by the M'Naghten Rules in 1843. Knowledge at this time was limited on mental disorders so a modern definition should be used.
4.1.1 A wider range of options has stopped injustice for diabetics and epileptics, as previously the judge had to send the defendant to a mental hospital. Judges can now give them a supervision order or even an absolute discharge.
4.2 The definition of insanity is a legal, not medical one, which is causing issues. People suffering from mental disorders cannot use the defence if they know their act is legally wrong but may have irresistible impulses, like in BYRNE. Even though they cannot prevent themselves from acting and have a recognised mental disorder they cannot use the defence of insanity.
4.3 Social stigma comes with the word 'insanity' so is it fair to be deeming those with physical disorders like epilepsy and diabetes insane? This has led to defendants pleading guilty to avoid the social stigma.
4.4 The burden of proof that D is insane is on him. It could be argued this is a breach of the European Convention of Human Rights which states the defendant is innocent until proven guilty.
4.5 The jury have to decide whether the defendant is insane or not but is this appropriate? Shouldn't a medical expert deal with matters where medical evidence is used as it can be technical?
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