If memory serves, the definition of extreme intoxication is found in subsection 33.1(4). The solution is not complicated: in this provision, extreme intoxication should be defined as intoxication akin to automatism or insanity. This would cover all manifestations of extreme drug intoxication. In fact, it would simply repeat the language used by the Supreme Court in Daviault, which referred to extreme intoxication at the threshold of automatism or insanity. The concept of extreme intoxication at the threshold of insanity could simply be added to the definition in subsection 33.1(4). This would cover all facets of extreme intoxication, even the rarest of cases, such as the one in Brown, where the person falls into a state of automatism and becomes like a robot. In that case, the person went into a state of delirium as a result of substance-induced intoxication, which is very rare indeed. I have only seen two cases like this in my entire career. I've talked to psychiatrists, and they say exactly the same thing.
This addition to the definition would also cover cases of psychosis. After using drugs, some people develop delusions of persecution or hallucinations. The cases Ms. Jules mentioned earlier are cases of psychosis.
If one were to speak of extreme intoxication akin to automatism or insanity, one would cover all facets of extreme intoxication. Then there would be no problem; that's certain.