I think others have done an excellent job of explaining how this could and likely will go wrong, but I wanted to add:
Firstly, I am not an addict, though I do have a history of drug abuse as a teenager/young adult. Second, although I am not an addict, the psychiatrist I see primarily treats them. Every time I go in (funny enough, I have to today) I hear all about how she won't prescribe their -insert controlled substance here- because they're an addict. They have to do piss tests every time they go in and some are called for random drops, and many of those called for random drops don't have transportation. They are looked at as liars and generally disregarded. Plus you have to wait 2-4hrs to be seen, even if you have a scheduled appt time. The doctor doesn't come in until she decides to, which is usually around 11-11:30, but they schedule appts for her to see people starting at 10, when they open. It's an incredibly fucked up system and there's such a lack of options for help here, particularly for those on state insurance, that she's all there is. And she pushes brand new drugs onto people who then have to mostly rely on her sample packs. Drug reps are in and out of there all day. Everything about it is enraging. So yeah, -5/10 do not recommend, friend.