Hm. I'm not expressing myself clearly here, but are there legal precendents/frameworks for that sort of thing? Where a majority of people would prefer to have not been offered a certain choice after making it, so in some ways the democratic/maximum-freedom thing to do would be for the government to remove that choice?
As far as I'm aware, there's no precedent for that sort of thing, or at the absolute least none that have managed to stand up to challenge. (Un)fortunately, "you're probably going to friggin' regret this and it makes it much more likely you're going to die" generally isn't sufficient for legal enforcement on its own.
Most things, so long as whatever smear you leave behind isn't on someone else or their property, it's sketchy as hell to build a legal framework from that angle that's not riddled with problems as great or greater than whatever you're trying to stop. Direct/short term suicide (gun to the head as opposed to binge eating and never exercising, ferex) has better luck, but most legal systems I'm aware of aren't going to do much to stop stuff where you have years to change your behavior.
... now, if you still want to legally minimize, there's plenty of ways, mind you. No public usage, strict regulation on product quality, vice taxes, public programs educating people on the subject, so on. Increased medical cost burden, etc. Make it a pain in the ass to support the addiction and supply its material... you generally don't want to be/can't get away with directly criminalizing use (you want an example of how that fucks up, just look at the USA's war on
suffrage drugs or the whole roaming vigilante death squad thing the occasional country indulges in, and so on.), but you often can for related stuff.
Part of it's kicking an addict while they're down, but it's stuff you can do.