Unit 3 defences: Insanity (2) A disease of the mind (Hennessy: D is…
Unit 3 defences: Insanity
Insanity is a general defence, available to all crimes requiring mens rea. The burden of proof is on the defence.
There must be evidence from 2 medical professionals
Verdict: Not guilty by reason of insanity
The rules on insanity are based on the
M'Naghten rules 1843
which state that there must be...
2) Which is a result of a disease of the mind
3) Causing D not to know the nature and quality of their actions, or not to know what they were doing was legally wrong.
1) A defect of reason
1) A defect of reason
D's power of reasoning are impaired, making the incapable.
If D is capable of reasoning but choses not to, they will not get the defence.
D walked out of a supermarket with items in bag. she claimed it was absentmindedness due to depression. defect of reason does not cover confusion or absent-mindedness
2) A disease of the mind
This can be a
mental or physical
disease as long as it affects the mind
It is a legal term, not a medical disease
D suffered epilepsy, known t have fits and show aggression to hose who help him during a fit. he injured and 80 year old man during a fit. Epilepsy still affected the mind so it is covered even though its physical.
: D is diabetic. forgot to take insulin for three days. Then seen getting in to a stolen car. D said he had no recollection. This type of diabetes affects the mind and the disease be can any part of the body
- gets the defence
- doesn't get it
: D had taken insulin but forgot to eat to correct his sugar level. in this time he assaulted v. Could not get the defence as the attack was not caused by a disease of the mind but an external factor of not eating.
Sleep walking can get the defence as it is an internal factor and natural condition that comes from the mind.
: Voluntary intoxication can not get the defence as the alcohol/drug is an external factor.
: Voluntary intoxication and alcohol abuse created a disease of the mind. such as hallucinations which is internal.
3) Does not know the nature and quality of their actions
This refers to the physical character of the act.
D must not know that there act is legally wrong, not a question of morals
Codere: D cut his wife's throat thinking it was a loaf of bread. did not know his actions were legally wrong so can have the defence.
: Threw cutlery at the police station. medical evidence showed he was suffering a psychotic episode. had no idea what he was doing was wrong.
: Knew his actions were legally wrong when he gave his wife 100 aspirin. Said he would hang for this, indicating knowledge
: Heard voices from god to run over a holiday camp. Although he thought it was morally right he knew it was legally wrong.
Criminal Procedure ( Insanity and Unfitness to plead) Act 1991 imposes actions judges can take.
Hospital order - With or without restrictions
If D commits murder they must receive a hospital order