Alcohol makes people clumsy, easily irritated and more likely to overestimate their abilities, and that is already pretty close to the worst of the bunch. The worst behaviour in people I’ve seen is with cocain plus alcohol (plus loud parties) — but people who become unbearable in that state are also not my friends when they’re sober. Most other drugs don’t make people more destructive or aggressive. They might see funny stuff, or fall asleep, try to hug everyone, or some other weird things. Those things may also not be incredibly convenient for their environment, and may be dangerous to themselves, but it does not invert anyone’s moral compass or such. Any problematic consequences can be further reduced if the people who take a substance and those in their environment know what to expect and prepare accordingly.

That goes for alcohol as much as nicotine or any other drug. Assuming the GA world follows the principle that “bigger” spells require more concentration and ability, it’d be hard to imagine anyone accidentally summoning a world-ending elder god unless they wanted to, could already easily do it when sober but couldn’t find the courage without a drink or five. Or if they were so amazingly OP that summoning that elder god is something they could do by accident. But any universe that contains such people would either also contain people who could banish that god again, or it wouldn’t live long because someone would (either accidentally or on purpose) summon an elder god sooner or later anyway. If the existence of your plane depends on nobody ever dialing the wrong number, alcohol should be the least of your worries.

The only exception to this are of course secondary crimes committed to obtain drugs, which are a direct result of them being illegal to obtain. Which in turn means that removing those substances from the world in order to prevent magic users from using and doing dangerous stuff by accident, might trigger those same people to do things, intentionally, that might cause a lot more harm.

Anyway, I wish I was a teetotaller. People should probably *try* alcohol to better understand it, and a lot of people seem content to drink in moderation, but I have a problem. I’m just glad it doesn’t make me act evil or anything, mostly just cringe.

I’m of the opinion that your sobriety has little to do with the decisions you make, either before or after consuming alcoholic inebriants, save for how well-informed those decisions are and the degree of aptitude you can muster in executing them. They don’t seem to otherwise interfere with an individual’s motive structure, in my admittedly limited experience. Matters of law regarding inebriants are easily reduced to superstitious, pseudoscientific, or otherwise flawed understandings of the effect they have on a person, or a willingness to propagandize and thus spread such beliefs for dubious reasons – coupled with public outrage in some circumstances to maximize receptiveness to such messaging.

To be equally fair, though, there are plenty of other kinds of inebriants, some that actually possess the qualities that appear to be mistakenly attributed to alcohol, and I’d expect at least a few magical ones in the case where sufficiently sophisticated magic is available. So I’m willing to imagine the scenario you’ve presented, entirely decoupled from its original proposed cause, as that kind of world-ending stupidity hardly needs *some* individuals to be “under the influence” for it to occur.

Now imagine being able to conjure fireballs and arcane storms and portals to who-the-flying-heck-knows-where.

I’d conjure alcohol out of existence from the whole society myself for fear of risking someone summoning a world-ending elder god because he was drunk and wanted a Double Decker from Tak’o B-Ell at 4AM.