Nothing is actually addictive in it's own right. The effect it has on you is what is addictive. As KA said before many things are addictive even games. The addiction is the hormones and other shit it releases your body says it wants more of that feeling and your brains says CRACK because it only knows what you know, and that is, that crack gives you that feeling. Same applies to anything that triggers biochemical releases even a damn good game like FF7 or DC2. My body says, "Hmm I liked how I felt when I was playing FF7 I want that feeling again." so my brain in turn goes and convinces me that I can play FF7 to get that feeling back so I do.

I do beileve I mentioned to MJ before that anyone can let their body and mind control them and their actions. The real question is...can you control your body and mind? Even Sun Tzu agrees with me in fact he said that mastering yourself makes you fearless. This is because you know that you can say, "STFU YOU STUPID PIECE OF SHIT BODY!" and not cave in to it's demands.