To me, it looks like any society with some form of inequality will inevitably need a way for the lower classes to escape their daily struggles. In some countries it's hardcore religion; in some it's drugs; in some it's alcohol; in some it's mindless gambling... Affinity for one or the other depends on a number of factors, but eventually we have to accept at least one of them if we want to keep society stable in the long run.

Then people can get the help they need and be treated as a disease if they are addicted. Stealing etc and all the other crime that comes from addicts are still crimes.

You're kidding yourself if you think Japan doesn't have drugs and crime related to it. I've met many a Japanese who loves a good smoke. It's really hard for them to get good smoke in Japan with all that anti drug control. Does it mean it's stops them wanting it? No?

From what I understand you can just buy flutoprazepam and some other fairly hardcore sedatives, so people abuse those.