It's an interesting question, and my response to it will be mixed:
When it comes to certain substances like amphetamines and stimulants, my control has greatly, greatly increased, but it's only by learning from my mistakes, misusing those substances, in other words, that I learned this control. I wish that I could say, "yeah, well, I never really misused those substances to begin with, and I just sort of gained greater control over them with time..." but the truth is that, well, I was hooked and now, now I can take those substances once every so often and I know when enough is enough. But, part of that is that I don't feel the same euphoria either.
I often wonder... if those substances gave me the same euphoria today, would I still be hooked? And I think that yes, yes I probably would still be hooked. But now my jaw clenches, and I get all wired, and I don't feel the same level of confidence or see that same boost in performance.
When it comes to opiates, I think that my control has decreased, and I'm not at all ashamed to say that. (I don't think that anyone here should be ashamed anyway, but you know what I mean.) It's just that physical dependence bit, and I know that once I overcome that piece, I can stay "clean" or "not use" for however long as, for me and in my experience, the "mental cravings" just aren't very overpowering, not when it comes to opiates. But it's hard to not use when you get sick and such... know what I mean?