Do you feel as though you are easily addicted to things?
Mine is an odd case. I can get addicted to things such as smoking and drinking easily, but whenever it seems like it has become a problem then I will quit cold turkey without to much of a fuss. It goes in fazes like I smoke a shitload, but then I will be disgusted by it and drop it. Then I will try it again a month or so later and get REALLY hooked on it for a week or two before I quit again. I doubt I could ever become dependent on a substance though.