Insanity

Establishing Insanity

Insanity is a defence which has three elements: M’Naghten [1843] UKHL J16

At the time of the commission of the offence, the defendant was suffering from a ‘defect of reason’;
This defect of reason was due to a disease of the mind; and
The defect rendered the defendant unaware of act’s nature and quality or made him unaware the act was ‘wrong’.

A ‘Disease of the Mind’

Diseases of the mind do not necessarily line up with what medical professionals would call mental illness. It covers any internal medical condition which produces defects of reason, including from physical illnesses: R v Sullivan [1984] AC 156; R v Kemp [1957] 1 QB 399. External causes, by contrast, are excluded and may only be subject to the defence of automatism.

Diabetes: Note that hypoglycemia (too little sugar from an insulin overdose) is an external cause. Hyperglycemia (too much sugar from taking insufficient insulin) is an internal cause. Contrast R v Hennessy [1989] 1 WLR 287 with R v Quick [1973] 3 WLR 26.

Nature and Quality of the Act

This limb of the third requirement of the insanity defence applies where the defect of reason leads the defendant to not realise what he is physically doing: R v Sullivan [1984] AC 156. For example, if the defendant hits the victim thinking he is knocking a vase over, this limb would apply.

Appreciating Wrongs

This limb of the third requirement of the insanity defence applies only where the defendant believed he was acting legally: R v Johnson [2007] EWCA Crim 1978. This includes cases where the defendant falsely believed he had a defence (e.g. self-defence) because of a delusion: M’Naghten [1843] UKHL J16. If the defendant knew his acts were illegal, however, his appreciation of morality is irrelevant. This is true even if he was acting in accordance with an ‘irresistible impulse’: R v Kopsch (1925) 19 Cr App R 50.

Insanity, Negligence and Strict Liability

The defence of insanity is available even if the offence is one of negligence or strict liability: Loake v CPS [2017] EWHC 2855.

The Effect of Establishing Insanity

If the defence of insanity is established, the defendant is found not guilty by reason of insanity. While they are considered not guilty, they may still be subjected to incarceration under a hospital order: R v Birch [1990] 11 Cr App R (S) 202.

Criminal Defences Quiz

Test yourself on the principles governing when a defendant has a defence to a criminal charge.

1 / 31

People are under a duty to retreat rather than use force in self-defence is they are able. True or false?

2 / 31

Josephine commits a crime involuntarily because of a hyperglycemic episode. Which defence would you advise her to rely on?

Diminished responsibility

Insanity

Automatism

3 / 31

Josephine commits a crime involuntarily because of a hypoglycemic episode. Which defence would you advise her to rely on?

Automatism

Insanity

Diminished responsibility

4 / 31

What is the age of criminal responsibility in England and Wales?

5 / 31

Leo is trying to escape a burning building. The only way out is up a ladder, but that ladder is being blocked by Gareth. Gareth is frozen in fear and cannot move out of the way to let Leo pass, nor can he move up the ladder. Because they will both die if Leo does nothing, Leo pulls Gareth off the ladder, causing him to fall to his death. He is later charged with Gareth's murder. Is the defence of necessity available to him?

6 / 31

Celestine owes her drug dealer, Mia, a lot of money. On Sunday night, Mia tells her that if Celestine does not pay her back by Monday morning she will kill her daughter. Celestine tells her she does not have the money, so Mia tells her to mug Richard as he carries a lot of money on him at all times. Celestine tries to get help from the police, but they tell her they do not believe her. Celestine robs Richard, but is caught soon after and arrested. Can Mia rely on the defence of duress?

7 / 31

What are the three elements of the defence of duress?

The defendant was threatened with the death or serious injury of himself or another

The defendant was threatened with death or injury

The defendant’s actions were necessary to avert an irreparable and inevitable evil

The defendant was threatened with the death or serious injury of himself or a person they were responsible for

The threat was so great that it would overbear normal human resistance

The defendant was ordered or under pressure to commit crime

The defendant was ordered or under pressure to commit a specific crime

The defendant's actions were not disproportionate to the threat

The threat was enough to overbear the defendant's will

8 / 31

Is duress a defence to murder?

Yes, in all cases

Yes, but not where the defendant is threatened by another person

Yes, but not where the duress stems from circumstances

9 / 31

Atticus gets extremely drunk at a party, and commits an offence as a result. He claims the alcohol made him act involuntarily, and advances the defence of automatism. Will his defence succeed?

10 / 31

Celestine owes a loan shark, Mia, a lot of money. On Sunday night, Mia tells her that if Celestine does not pay her back by Monday morning she will kill her daughter. Celestine tries to get help from the police, but they tell her they do not believe her. Celestine then robs a local corner store to get the money to pay back Mia, but is caught soon after and arrested. Can Mia rely on the defence of duress?

11 / 31

Celestine is driving when she feels the onset of a hypoglycemic episode. She is not able to pull over in time before the episode starts. She is barely in control of her body, but is able to move the steering wheel a little and as a result is able to avoid hitting pedestrians. She eventually collides with a tree. Can Celestine rely on the defence of automatism in relation to any criminal offence she is charged with?

Yes, because her actions were substantially involuntary and had an external cause

No, because she maintained some control over her actions

No, because her actions did not have an external cause

12 / 31

What three elements must be shown to establish the defence of necessity?

The defendant did no more than he thought necessary

The crime was necessary to stop serious and unfixable harm

The defendant's actions were not grossly disproportionate

The defendants actions were proportionate

The crime was necessary to stop a certain and unfixable harm

The defendant did no more than reasonably necessary

The crime was necessary to stop likely serious harm

13 / 31

Can the defence of self-defence be relied on if the defendant provoked the victim to attack?

Yes, in all cases

The law is unclear

Yes, but only if the victim escalates beyond what the defendant intended

14 / 31

When determining whether a sober and reasonable person would have succumbed to a duress, what characteristics of the defendant is the hypothetical person given?

Any characteristics which bear on the gravity of the threat

Age and gender only

Age, gender, pregnancy and serious physical/mental illnesses only

All characteristics relevant to the defendant's firmness

Age, gender, pregnancy, serious physical/mental illnesses and self-induced conditions such as drunkenness

15 / 31

What three elements must the defendant show to rely on the defence of automatism?

Their actions were triggered by a defect of reason

The cause of their actions was not induced by the defendant

The defendant induced the cause of their actions

The victim induced the cause of the defendant's actions

Their actions had an internal trigger

Their actions were at least partially involuntary

Their actions were totally involuntary

Their actions had an external trigger

16 / 31

Omar takes prescription medicine for depression. One day, he has a rare reaction to the medicine which causes him to involuntarily commit a criminal offence. The prosecution argue that he cannot rely on the defence of automatism, because he voluntarily took the medicine which caused the automatism. Will this argument succeed?

17 / 31

For the purposes of the defence of insanity, a disease of the mind may be caused by any internal or external trigger. True or false?

18 / 31

Can an adult be convicted of being an accessory to a crime committed by a child under the age of criminal responsibility?

19 / 31

Insanity is not a defence to an offence of negligence or strict liability. True or false?

20 / 31

Micah mistakenly believes that Joseph is threatening to kill her unless she robs a bank. Can she rely on her mistaken belief to establish the defence of duress?

Yes, but only if she honestly believes it

No, the threat must be real

Yes, but only if the belief is reasonable

21 / 31

For the purposes of the defence of insanity, a disease of the mind includes mental illnesses and not physical illnesses. True or false?

22 / 31

Moira, a teenager, joins a local gang to obtain protection against bullies at school. She knows that the gang have engaged in violent robberies in the past, but the gang leader promises her that they will not involve her in these as she is too young. The gang later threatens to cripple her mother if she does not hold onto a package of drugs for them. Can Moira rely on the defence of duress when charged with drug possession?

23 / 31

When establishing self-defence or defence of others, can the defendant rely on any mistaken beliefs as to the circumstances that are the result of his being voluntarily intoxicated?

24 / 31

Is the defence of necessity available to an offence of strict liability?

25 / 31

Micah is charged with stealing drugs from a pharmacist. They rely on the defence of duress, arguing that they were under the threat of serious injury or death as they were withdrawing heavily from medication at the time. Is the defence likely to succeed?

Yes, because the threat was serious and overbore Micah's will

No, because Micah was threatened by her circumstances and not another person

No, because the threat did not arise from an external source

Yes, because the threat was serious and would overbear a reasonable person's will

26 / 31

What are the two elements of the defence of persons defence?

A reasonable person with the defendant's factual beliefs would think that the level of force used was reasonable

The defendant honestly believed that the level of force used was reasonable

The defendant honestly believed that it was necessary to use force to defence a person

A reasonable person holding only reasonable beliefs would think it necessary to use force to defence a person

A reasonable person with the defendant's factual beliefs would think it necessary to use force to defence a person

The victim was not a police officer

A reasonable person holding only reasonable beliefs would think that the level of force used was reasonable

27 / 31

Lucy, Theo and Marius were trapped in a sinking ship. To buy time pending the arrival of a rescue vessel, Lucy threw Theo overboard. Theo drowned. Lucy has been charged with murdering Theo. She proves that if she did not kill Theo, the ship would have sunk and she and Marius would have died. Can she rely on the defence of necessity?

28 / 31

Can the defence of self-defence be relied on where the force is used pre-emptively?

Yes, but only if the defendant is under the threat of death or serious injury

Yes, but only if the victim has a weapon

Yes, but only if an attack is imminent

The law is not clear

29 / 31

What are the two elements of the defence of insanity?

The defect makes the defendant unaware of the nature and quality of his actions or subjected him to an irresistible impulse

The defect makes the defendant unaware of the nature and quality of his actions or rendered him unaware the act was morally wrong

That at the time of the offence, the defendant suffered a defect of reason stemming from a disease of the mind

The defect makes the defendant unaware of the nature and quality of his actions or rendered him unaware the act was illegal

That at the time of criminal charge, the defendant suffers a defect of reason stemming from a disease of the mind

That at the time of trial, the defendant suffers a defect of reason stemming from a disease of the mind

30 / 31

When establishing the defence of duress, what three elements must exist before the impact of the threat on the defendant is considered sufficient?

The defendant must reasonably believe in the circumstances constituting the threat

The defendant must have good reason to fear death or serious injury

The defendant must honestly fear death or serious injury

The defendant must honestly believe in the circumstances constituting the threat

A sober and reasonable person with the defendant's characteristics but ordinary firmness would have acted the same way

The defendant suffered some physical or mental illness which made them unusually susceptible to threats

A person with the same characteristics as the defendant would have acted the same way

31 / 31

Ellen is 17 years old but suffers from a developmental disorder which gives her the emotional maturity of a 7 year-old. Can she escape liability on the grounds that she lacks criminal responsibility?

No, because she is over the age of criminal responsibility

Possibly, because the prosecution is required to prove she understands right and wrong

Yes, if the defence shows that she did not understand right and wrong

Your score is

Criminal Law: Insanity

Insanity

Establishing Insanity

A ‘Disease of the Mind’

Nature and Quality of the Act

Appreciating Wrongs

Insanity, Negligence and Strict Liability

The Effect of Establishing Insanity

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Insanity

Establishing Insanity

A ‘Disease of the Mind’

Nature and Quality of the Act

Appreciating Wrongs

Insanity, Negligence and Strict Liability

The Effect of Establishing Insanity

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