Generally, intoxication does not excuse a criminal act where the accused has the requisite intent. As it were a "drunken intent is nonetheless an intent."
The law recognizes three degrees of intoxication:
- Mild Intoxication: alcohol-induced relaxation of inhibitions and acceptable behaviour. This does not affect the mens rea of an offence
- Advanced Intoxication: intoxication to the point of the accused lacking any specific intent to an offence. There is a impairment of the accused's foresight of the consequences of his acts, raising a reasonable doubt on the requisite mens rea. This will only apply to specific intent offences.
- Extreme Intoxication: intoxication to the point of automatism-like state. This degree of intoxication negates the voluntariness of the accused's actions. It is a rare defence that only applies to non-violent offences (as per s. 33.1)
Offences of Violence
When defence not available
33.1 (1) It is not a defence to an offence referred to in subsection (3) that the accused, by reason of self-induced intoxication, lacked the general intent or the voluntariness required to commit the offence, where the accused departed markedly from the standard of care as described in subsection (2).
Criminal fault by reason of intoxication
(2) For the purposes of this section, a person departs markedly from the standard of reasonable care generally recognized in Canadian society and is thereby criminally at fault where the person, while in a state of self-induced intoxication that renders the person unaware of, or incapable of consciously controlling, their behaviour, voluntarily or involuntarily interferes or threatens to interfere with the bodily integrity of another person.
(3) This section applies in respect of an offence under this Act or any other Act of Parliament that includes as an element an assault or any other interference or threat of interference by a person with the bodily integrity of another person.
1995, c. 32, s. 1.
Section 33.1 will exclude intoxication as a defence for general intent offences or involuntariness due to intoxication where the following conditions are met:
- the accused was intoxicated at the time of the offence;
- the intoxication was self-induced; and
- the accused departed from the standard of reasonable care generally recognized in Canadian society by interfering or threatening to interfere with the bodily integrity of another person
This section applies to any mental condition that arises directly from a state of intoxication, including toxic psychosis.
- R v Bouchard-Lebrun, 2011 SCC 58 (CanLII),  3 SCR 575
A determination of intoxication must be made "in light of all the circumstances".
Simply establish evidence of consumption of alcohol is not sufficient to rely on intoxication as a defence.
- R v Holland, 2013 NBCA 69 (CanLII), at para 20
- Holland, at para 20