I too have an Addictive personality, since I was about 16 I have really noticed it in day to day life (I'm 22 now). I tend to go through phases with my addictions, (or maybe some of them are habits). I still smoke cigarettes, i quit once for 3 months though. I smoked lots of weed for about 3 days, every day for a while, but once a started to get bad anxiety attacks, I managed to stop that and have only had the odd puff every couple of months. Alcohol only gets to feel like an addiction for me when I get into the habit of opening a cold beer as soon as I get home from work everyday, then It turns into 6 beers. Hell, I'm even addicted to the Internet. And some foods. The worst addiction for me has been ecstacy and LSD, if it's not readily available to me I'm fine without it. But once I come into contact with a source for these drugs I have to have them, and I can see it affecting my life badly!
The one thing that helps me with all this is a complete change of habits, like moving to a new town, with a new job, new house and new people. This way you can develop new habits, new routines, and hopefully get dampen down some of your addictive personality traits. Doing this hasnt magically "fixed" anything for me, but it has made it a little easier to slow down and eventually cut something out of my life. Hope that helps, and remember you're not the only one!