The effect of self-induced intoxication upon the mental element of an offence is set out in Pt 11A Crimes Act 1900. In effect, Pt 11A divides offences committed after 16 August 1996 into two types: (a) offences of specific intent, and (b) other offences.
Offences of specific intent are set out in s 428B of the Act and are offences “of which an intention to cause a specific result is an element”. Generally, intoxication (however caused) is relevant to whether the accused had the necessary specific intention at the time when the act was committed giving rise to the offence: s 428C. It does not extend to the basic or general element to commit the act: Harkins v R  NSWCCA 263 at , . Although offences involving recklessness are not included in s 428B (even where recklessness is proved by intent), reckless murder is an offence of specific intent: R v Grant (2002) 55 NSWLR 80.
For other offences, self-induced intoxication cannot be taken into account when determining whether the person had the mens rea of the offence: s 428D.
Where evidence of intoxication results in the accused being acquitted of murder, self-induced intoxication cannot be taken into account in determining whether the person has the requisite mens rea for manslaughter: s 428E. As to intoxication and Substantial impairment because of mental health impairment and cognitive impairment see [6-550]; Self-defence see [6-470]ff; Indecent assault see [5-600]; Sexual intercourse without consent (for offences alleged before 1 January 2008 see [5-800] and offences alleged thereafter see [5-820]).
Where a reasonable person test is applicable, the reasonable person is one who is not intoxicated: s 428F. Self-induced intoxication cannot be taken into account on the issue of voluntariness: s 428G.
The application of Pt 11A gives rise to some apparent anomalies that may complicate a summing-up. For example, the offence of robbery is not an offence of specific intention (it is a stealing accompanied by threats or violence) but an assault with intent to rob is an offence of specific intent. Yet often the assault offence will be an alternative to the completed offence.
As to intoxication see generally Criminal Practice and Procedure NSW at [8-s 428B.1] and Criminal Law (NSW) at [CLP.1180].
[3-255] Suggested intoxication direction — offence of specific intent
It is erroneous to direct the jury in terms of whether the accused had the capacity to form the relevant intent and a direction in those terms may give rise to a miscarriage of justice: Bellchambers v R  NSWCCA 235. The issue is whether the accused formed the specific intent referred to in the charge notwithstanding his or her intoxication.
It may be disputed on the evidence whether a defendant was intoxicated and whether any intoxication was so extensive as to affect the formation of the relevant intent. There must be sufficient evidence so that it is fit to be considered by a jury, but it is not a demanding standard and can still include substantial, and even reasonable, doubts on those issues: Cliff v R  NSWCCA 15 at .
It is suggested that the jury would be assisted by written directions in a case where intoxication is relevant to some counts but not others.
In considering the question of whether the Crown has proved that [the accused] had the intention to [specify the required intent] one matter that you need to consider is the effect upon [the accused] of the [alcohol/drugs] which [he/she] says [he/she] consumed. Whether [the accused] was affected by [alcohol/drugs] at the relevant time and the degree of that intoxication are issues for you to consider. But as a matter of law, intoxication by alcohol or drugs is a relevant matter to be taken into account in determining whether an accused person had formed the intent to commit the offence charged. When I am speaking of intention at this time, I am not referring to the intention to commit the acts relied upon by the Crown that give rise to the offence alleged [specify acts relied upon if necessary]. I am referring to the specific intention that is stated in the charge, which is [identify the specific intention alleged]. [In murder it will be the state of mind relied upon by the Crown including reckless indifference.] [The accused’s] intoxication is only relevant to that issue.
It is for the Crown to satisfy you beyond reasonable doubt that [the accused] had the intent to [specify the intention] in spite of the evidence of [his /her] consuming [alcohol/drugs] before the alleged conduct giving rise to the charge. If the Crown fails to satisfy you beyond reasonable doubt on that issue [the accused] must be acquitted of [the offence of specific intent].
In some circumstances, an intoxicated person may act without forming any particular intention at all. On the other hand, a person may be considerably affected by alcohol and/or drugs and yet still commit an act with a specific purpose in mind. The fact that the person may have no recollection of the incident afterwards does not necessarily mean that he or she was not acting with a specific intention at the time of the incident. The fact that his or her judgement was affected so that the person acts in a way different to how he or she would have acted if sober does not necessarily mean that the person was not acting with a specific intention. For example, if a person in a drunken fury picks up a hammer and hits another over the head with it, there may be little doubt that the person intended to cause the other really serious harm, even though the judgement of the person using the hammer was affected by alcohol.
[Set out the evidence and arguments by the accused relied upon for asserting that he or she did not have the specific intention required to prove the offence and the Crown’s response.]
Having considered the evidence and arguments on this issue the question for you is whether, having regard to the evidence of [the accused’s] intoxication, you find the Crown has proved beyond reasonable doubt that [he/she] acted with the intention to [specify the specific intention]. Keep in mind that there is no obligation on [the accused] to prove either that [he/she] could not or did not act with that intention. It is an essential fact that the Crown must prove before you can find [the accused] guilty of the offence charged.
[Where there is an alternative charge add
If the Crown fails to satisfy you that, for whatever reason, [the accused] did intend to [specify the specific intention stated in the charge], you would find [the accused] not guilty of the first count on the indictment. If you came to that decision then you would consider the alternative charge of [specify the alternative charge relied upon by the Crown].]