Defences+of+Intoxication+and+Mental+Impairment

**Intoxication**
The defendant bears the evidential burden of proving that they were intoxicated to such a degree that the jury could find that a reasonable doubt exists as to whether not the act was reasonable or whether they had formed the requisite mens rea.

**Actus Reus**

 * Intoxication is only relevant to the actus reuse insofar as the defendant may claim that their actions were involuntary.
 * However, the level of intoxication required to prove that the act was involuntary is very higher per __R v Cottle__. In other words, they must be so drunk that they are not conscious or aware of their actions. Clearly, there is a very fine line between this level of drunkeness and unconsciousness and hence the difficulty of proving that the act was involuntary.

**Mens Rea**

 * The defendant may argue that due to the intoxication that they did not intend or advert to the consequences that subsequently occurred. THe level of intoxication required to argue this is less than that required to refute the actus reuse element.
 * The mens tea is always assessed subjectively, so if the defendant sufficiently proves intoxication to fulfil their evidential burden then the judge must direct the jury to take intoxication into account when making their decision.
 * In R v O'Connor, the court rejected the UK decision in R v Majewski that intoxication is not a defence if the intoxicant was consumed voluntarily.
 * Thus, according to R v O'Connor, intoxication is a defence to mens tea offences, if it can be established that the defendant did not hold the requisite mental state necessary for the offence.

**Mental Impairment**
Under s20(2) of the Crimes (Mental Impairment and Unfit to be Tried) Act 1997 (Vic) mental impairment is established as a complete defence to all crimes and will result in an acquittal.

In order to establish mental impairment, the defence must establish that, on the balance of probabilities:
 * 1) They suffered from a disease of the mind; and
 * 2) The disease caused such a defect to their reasoning that the defendant was not aware of the nature of quality of their act, or alternatively, that the defendant was not aware that his or her acts were 'wrong' in the relevant sense.

__'Disease of the Mind'__ The term 'disease of the mind' is not limited to mental diseases or psychoses and includes any physical conditions (see Bratty v AG for Northern Ireland and Reg v Kemp) that affects the "workings or sounds of the mental faculties" per R v Falconer.

According to R v Falconer there are exempting qualifications on the term 'disease of the mind'. The disease must not be:
 * transient
 * caused by trauma, whether physical or psychological, which the mind of an ordinary person would be likely not to have withstood; and
 * not prone to occur