I think it's worse than that. I think some of them take illicit drugs because they hate being that way and are trying to control it in the absence of a proper diagnosis and proper intervention. And then they get vilified as "addicts" for self medicating to keep themselves chilled out.

Edit: And of course there will always be the assholes with an excuse for their intentionally malicious behavior, which complicates the hell out of finding good solutions.