He has an ongoing heroine problem (as these things often are) that he's trying very hard to deal with and overcome. He may slip back several times before he kicks the habit, if he manages to kick it at all.
If that means he's a smack head, then yes, you're correct, but using the term to describe people in his situation isn't really helpful to anyone.
Hate to say this but I think he's done remarkably well out of his addiction-how many of us can see we'd heard of him before all these drug related stories came out? I know I hadn't!
I personally think it's disgusting that he's somehow more famous because of this- same goes for his girlfriend too. Whilst I'm not disputing that she's not the only model (probably) to take class A drugs, she's one that got caught.....so why is she still able to 'work'.?......not a good example to the yoooooooooooff of today!