Criminal Defence: Insanity

What test was the defence of insanity outlined under and what as?

The McNaughten Rules 1843 - ‘All defendants are presumed to be sane, until the defence proves otherwise. If insanity is proven the D will recieve a special verdict of ‘not guilty by reason of insanity’.’’

What 3 steps are needed to prove the defence of insanity?

1. Defect of Reason

2. Due to a disease of the mind

3. Which meant that the D did not understand the nature and quality of his act, or if he did he did not know what he was doing was wrong.

1. Defect of reason

D’s power to reason is impaired. If the D is capable to reason, the defence fails.

Clarke - D stole mincemeat from the shop because of depression. Defence failed as a moment of absent mindedness is not equal to a defect of reason.

2. Disease of the mind

D must prove he was suffering from a disease of the mind at the time of the actus reus of the offence. A disease of the mind is ‘‘any illness which affects memory, reasoning or understanding caused by an internal source’’ Kemp - D beat wife with a hammer due to an artery issue which prevented oxygen reaching the brain.

Epilepsy

Sullivan - D injured 80 year old man during a seizure. Defence would have succeeded however he chose to plead guilty instead of using the defence.

Sleepwalking

Burgess - D was charged with s.18 wounding and held that sleepwalking could lead to a defence of insanity

Dissociation

T - D took part in a robbery and was also charged with ABH. D claimed she was in a dissociative state caused by PTSD from rape.

Courts instead held that PTSD was an external factor so the D recieved automatism instead

Diabetes

Hyperglycemia (no insulin taken) = Insanity

Henessy - D did not take insulin for 3 days so cause of defect of reason was internal. Defence of insanity succeeded.

Hypoglycemia (too much insulin taken) - Automatism (low=hypo=auto)

Quick - D took insulin but ate very little. Cause of episode was external so the defence was automatism.

Voluntary intoxication

If the D voluntarily takes an intoxicating substance which causes a psychotic episode, D cannot use the defence of insanity as the intoxicating substance is external.

3. D did not understand:

1. The nature or quality of his act (Oye - D was found drinking water from a toilet after punching a police officer)

2. or if he did, he did not know that what he was doing was legally wrong. Windle - D poisoned his wife and after being arrested said ‘I suppose they will hang me for this’ implying he knew it was legally wrong so the defence failed.

The special verdict

If insanity succeeds D will be found not guilty by reason of insanity. This is known as the special verdict.

Since the Criminal Procedure Act 1991, hospitalisation is now only mandatory for murder and discretionary for other crimes.