Folks here, and I imagine a considerable number not here, have misinterpreted/overinterpreted the ruling. Deliberate self-induced intoxication is still not considered to be a non compos mentis defense. As I understand it, in none of the 3 cases that the appeal was based on, was alcohol involved, or indeed any other substance the individual ingested/self-administered increasingly larger amounts of. The rationale of the appeal was that there can be some instances where an individual is rendered non compos mentis by a drug whose dosage was uncalibrated, whose effects were unpredicted or unknown, and completely interfered with the individual's judgment. The law, as it existed before the ruling was that a non compos mentis defense could only be used if there was unambiguous evidence of inability to assess right and wrong, or the consequences of one's actions, due to compromised mental state. Drug-induced states were not to be considered part of that defence. The argument presented by the appelant, and accepted by the court, was that this is to be differentiated within the law from someone who gets deliberately and progressively more wasted and then commits a felony of some kind with intent. In one of the 3 cases, the defendant had taken "magic mushroom" at a party (and I wouldn't waste my breath asking the guy if he knew how much he had taken), and was wandering around the streets naked, in the middle of winter, before entering a home and attacking the woman there. Was he in any state to know he was committing a crime? No. Could he have known in advance that his indulgence at the party would have turned him into that sort of idiot? No.
If someone goes to a party, gets progressively more drunk as the night goes on, snuggles up beside some sweet young thing sleeping off her own binge, and then undoes both their pants and starts to take advantage of that,he's still on the hook for sexual assault and cannot use "But I was drunk, your honor" as a defence. The distinction upheld by the court is between causes/degrees of intoxication that can make it functionally equivalent to non compos mentis, and those causes/degrees which do not. There is no free-for-all in the works. The original changes to the criminal code were intended to prevent any free-for-all, but as the successful appeal indicated (and persuaded) there can be circumstances, and drug states, where the individual/perp is quite literally out of their mind, and should be treated as not criminally responsible.
Having said that, I can't see this as case-closed, and expect there to be future cases wherethe defense tries o make the case that non compos mentis applies but the prosecution and court argue it doesn't in this instance for this and that reason. The law wasn't designed to differentiate between different sorts of drugs and drug states with surgical precision. It's something that will be worked out along the way.
