Under section 33.1 as well as the traditional approach taken in Leary, an accused may be convicted of a general intent offence on the basis of the fault or recklessness of voluntarily becoming intoxicated. This raises the question of what should the courts do if the accused becomes involuntarily intoxicated through no fault of his or her own? If the accused is to be held at fault for a general intent offence for voluntarily becoming intoxicated, it is only fair that he or she not be convicted if the intoxication was not the accused’s fault.81
The Supreme Court has long recognized that involuntary intoxication raises special issues. In R. v. King,82the Court indicated that an accused who had been impaired by a drug given to him by his dentist should not be convicted of impaired driving if he "became impaired through no act of his own will and could not reasonably be expected to have known that his ability was impaired or might thereafter become impaired when he undertook to drive and drove his motor vehicle." It is also significant that the 1962 case of King seems to acknowledge that there could be a degree of intoxication that is inconsistent with the formation of the mens rea of a general intent offence such as impaired driving. King is consistent with Daviault in suggesting that involuntary intoxication can be a defence that may negate either the mens rea or the actus reus of a general intent offence. Evidence of either voluntary or involuntary intoxication could also be considered in determining whether the accused had the mens rea of a specific intent offence. At the same time, King places a restriction on the involuntary intoxication defence by requiring not simply that the accused not know that the substance might impair, but also that the accused could not reasonably know that the substance would impair.
King has been applied in a case in which the accused went into an automatic state and assaulted another person after overdosing on
prescription pills that contained no specific warnings83or was surreptitiously given vodka in his drink.84It has been distinguished in cases in which the accused were convicted of impaired driving caused by overdoses of cold medication;85and by a deliberate overdose of prescription pills in an attempt to commit suicide.86...