I didn't downvote, but others may have downvoted because you didn't give any sources, and you don't expand on your statement. Yes, there are fewer drug users in Singapore and Japan, but they are historically and culturally extremely different to the USA.

I'm not convinced on Indonesia[1] and Hong Kong[2]; I've visited both myself several times, and drugs were easily available.

[1] http://jakartaglobe.beritasatu.com/news/bnn-says-33-die-of-d... [2] http://www.scmp.com/magazines/post-magazine/article/1826366/...