Just my tuppence worth, I've a family member that was an addict.
For years he managed to hide it, even holding down a job for the whole time. He's now a family man with his own business, nice house, nice car, doesn't touch anything that might cause him to lapse, even alcohol.
He also does a bit of work with helping addicts come away from drugs, counselling etc.

If he can come through the other side then so can anyone.