If you fall into depression and go on the way of drugs, those drugs that create dependence, then it's out of your control at that point. You're going to LIVE for the drug itself. The only thing you will really care about is how to take your next dose.
Are you doing yourself a huge disservice getting your first dose? Yes. But from that point on you become another kind of person/animal and you can't really be held responsible since your whole physiology changes, behavior etc.
