The reality is, a lot of people self-medicate for their own anxiety/depression/PTSD/various other mental issues with legal (and/or illegal) drugs, and another lot of people use them for "fun", and that's not going to change regardless of legislation, period. People who are mentally ill are too desperate, and people who're willing to try anything to get high are too careless for laws to make a difference. If anything, experiments like the legalization of drugs in Portugal show that making drugs legal actually improves things, if nothing else because people are more likely to seek help when they find things are getting out of control (instead of avoiding it for fear of being imprisoned for using illegal drugs). Not to mention that legalization eliminates incentives for things like drug trafficking, with its associated brutal drug cartels, etc. I always find it curious how people are very horrified by the things ISIS does, while ignoring the equally (or more) brutal things that drug cartels in various countries do.

If we were to address this issue rationally (not that people care), we would look at the science literature (and perhaps conduct more studies) to find what recreational or potentially recreational drugs are least harmful, and then we'd make that information available to the public, and let them use whatever they want. Either that or we'd create Soma (the Huxley Soma, not the lingerie Soma). But all of these things are antithetical to governments that are (1) owned by corporations, e.g. pharmaceutical industries, and/or (2) subject to replacement by an electorate that sees drugs as an evil sin shunned by their favorite imaginary friend in the sky (even if they're using them anyway).

As with everything, the main two things standing in the way of progress are greed and religion. No surprises.