Yeah, I'd go with "depends on the drug and the jurisdiction". Some offhand guesses for the major Pact World planets. . .
1. The Burning Archipelago: I doubt the Sarenites are especially puritanical, so only stuff that's especially addictive or harmful is outlawed. If you let your vice get out of control, though, expect to be dragged into rehab.
2. Aballon: The Insight Array probably has an elaborate code of fair but firm rules on drug legality, both conventional and electronic. Don't disrupt the peaceful and productive operation of society with your uncontrolled use of addictive practices.
3. Castrovel: The Formians probably ban anything harder than the equivalent of booze. The Elves likely permit anything. The Lashunta are diverse, varying by city-state, with a baseline probably of "Do what you want as long as it doesn't endanger others".
4. Absalom Station: The sheer disunified nature of governance and power probably means only the most severely addictive drugs are banned. If your drug isn't going to literally turn you into a violent killer, nobody has time to worry about whether some people decide to poison themselves.
5. Akiton: Some municipalities might conceivably ban some or all drugs, but I doubt anyone cares especially. Anything goes, much moreso than Absalom Station. In fact, this is probably one of the hotbeds for testing of new drugs.
6. Verces: Probably some of the tightest drug regulations in the system, due to the well developed, highly lawful, pro-social society. Doesn't mean no one alters their mind with chemicals, but its either within established social norms for such, or its pretty illegal. Needless to say, this goes out the door outside the Ring of Nations, though the harshness of survival mitigates against undue addiction.
7. The Diaspora: The Sarcesians likely ban all drugs which aren't socially approved, due to strict survival demands. Everyone else doesn't care, unless your addiction seems likely to get others killed. Then, you get booted off the asteroid ( or out an airlock ).
8. Triaxus: Varies by nation, though I can't imagine most of the chromatic dragons being opposed to their subjects drugging themselves into submission. Their opponents, meanwhile, probably view undue intoxication as "weaken us against those who would enslave us".
9. Liviara: The Dreamers don't care, though their wardens probably do keep an eye out for intoxicated visitors doing dumb stuff. Otherwise, varies by locale/moon.
10. Bretheda: I can't see the Barathu caring about drugs at all, not when radical self-alteration of physiology and neurology is a universal racial trait. Insofar as they regulate drugs at all, its probably purely in terms of harmful behavior on the part of non-Barathu. Otherwise, varies by moon.
11. Apostae: The Drow don't care what drugs you want to snort. In fact, do you want to buy some, we have great prices!
12. Aucturn: On Aucturn, you will wish you could enjoy something so pleasant as methamphetamine withdrawal. . .
