Defences Involving State of Mind Flashcards Preview

CIB 013 - Homicide Law and Defences > Defences Involving State of Mind > Flashcards

Flashcards in Defences Involving State of Mind Deck (12)
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(2) Definition

No person shall be convicted..........

S23(2) CA61

No person shall be convicted of an offence by reason of an act done or omitted by him when labouring under natural imbecility or disease of the mind to such an extent as to render him incapable—

(a) Of understanding the nature and quality of the act or omission; or
(b) Of knowing that the act or omission was morally wrong, having regard to the commonly accepted standards of right and wrong.

Of note

(1) Every one shall be presumed to be sane at the time of doing or omitting any act until the contrary is proved.

(3) Insanity before or after the time when he did or omitted the act, and insane delusions, though only partial, may be evidence that the offender was, at the time when he did or omitted the act, in such a condition of mind as to render him irresponsible for the act or omission.


R v Cottle

Burden of proof for insanity

R v Cottle

As to degree of proof, it is sufficient if the plea is established to the satisfaction of the jury on a preponderance of probabilities without necessarily excluding all reasonable doubt.

Of note

Thus, the defendant is not required to prove the defence of insanity beyond reasonable doubt, but to the satisfaction of the jury on the balance of probabilities.


R v Clark

The decision as to an accused’s insanity

R v Clark

The decision as to an accused’s insanity is always for the jury and a verdict inconsistent with medical evidence is not necessarily unreasonable. But where unchallenged medical evidence is supported by the surrounding facts a jury’s verdict must be founded on that evidence which in this case shows that the accused did not and had been unable to know that his act was morally wrong.


M’Naghten’s Rules

If a person is insane

It is based on the person’s ability to think rationally, so that if a person is insane

they were acting under such a defect of reason from a disease of the mind that they did not know:
• the nature and quality of their actions, or
• that what they were doing was wrong.


Disease of the mind

A term which defies precise definition.......

and Does not include.....

Of note only

A term which defies precise definition and which can comprehend mental derangement in the widest sense

Does not include a temporary mental disorder caused by some factor external to the defendant, such as a blow on the head, the absorption of drugs, alcohol, or an anaesthetic, or hypnotism.

Disease of the mind is not a medical question but a legal one.


R v Codere

Nature and quality

R v Codere

The nature and quality of the act means the physical character of the act. The phrase does not involve any consideration of the accused’s moral perception nor his knowledge of the moral quality of the act.

Thus a person who is so deluded that he cuts a woman’s throat believing that he is cutting a loaf of bread would not know the nature and quality of his act.




Automatism can best be described as:

A state of total blackout, during which a person is not conscious of their actions and not in control of them.


R v Cottle


Action without conscious volition

R v Cottle

Doing something without knowledge of it and without memory afterwards of having done it - a temporary eclipse of consciousness that nevertheless leaves the person so affected able to exercise bodily movements.

Of note

Another example of automatism is an act which is done by the muscles without any control by the mind - sleepwalking


Two types of automatism and example

Sane automatism - sleepwalking

Insane automatism - mental disease



The general rule has been that intoxication may be a defence to the commission of an offence:

• where the intoxication causes a Disease of the mind so as to bring Insanity into effect

• if Intent is required as an essential element of the offence and the drunkenness is such that the defence can plead a lack of intent to commit the offence

• where the intoxication causes a state of Automatism (complete acquittal).

Of note

Intoxication can be used as a defence in New Zealand to any crime that requires intent. Any offence that does not require an intent is called a strict liability offence and the only way a defendant can escape liability for such an offence is to prove a total absence of fault.

In cases of homicide and other crimes, evidence that a person formed an intent to commit a crime and then took drink or drugs as part of the method of committing the crime (gaining Dutch courage) will disqualify a defence of drunkenness or automatism.


Ignorance of law


The fact that an offender.......

S25 CA61

The fact that an offender is ignorant of the law is not an excuse for any offence committed by him.


What is the likely result of a trial where the defendant is found to have been in a state of automatism from intoxication?

Complete acquittal