I don't think I've told this story here before. TLDR: I lived in Japan, just outside of Tokyo, for a brief time and the amount of prostitution there was eye opening. But I never saw drug use.
I lived in Japan for about 18 months. A few years out of college my wife and I (then fiance) decided we hated our jobs. She is not Japanese but grew up there: her parents are UK expat educators (they're from Wales but of Puerto Rican ancestry and for reasons I forget both had close ties to Japan - worldly people obviously) who moved there when she was yet unborn. She also has two sisters who still reside there - completely integrated. She came to the US for college and that's where we met.
Anyways. So we decided to quit our jobs, put our stuff into storage, and visit her homeland for a few months as we decided on what to do next. Long story short, the company of one her sisters hired her because they needed someone who had her niche expertise and was also fluent in various languages to deal with both domestic companies and those staffed by largely European expats. She speaks English, German, Japanese, and Spanish. I ended up getting a decent remote work IT contract job. So we kind of settled for a while.
I was never able to integrate. Japan is a weird place and it always felt like I was an outsider, being a pale-skinned 6' + tall guy who didn't know a lick of Japanese. But I ended making friends with several guys and a woman who were in various corporate jobs there but who grew up abroad so they spoke English. These guys, and even the woman, would have wild prostitute sex parties. Like all the time. A few each month, at least, sometimes more. I went to one not knowing what I was getting in to, and I did not partake. I left as things really started going down.
I later found out that it was pretty common amongst the high paid so called "salary man / women" in Tokyo. Not for me, but yea, that shit does indeed go down, and there's quite often a lot of foreigners involved. Especially from Eastern Europe.
*Edited for clarity