Honestly I've been all 3. Started off as a user, that lasted for a year or so. Then abuser for a good chunk of time, lets say 4 years or so. And there have been times in between the abuser periods where i've fallen into the addict category. but usually this happens once with a drug, i overcome it, and it never happens again. but this has happened with 4 different drugs, but now there really isn't any other drugs out there that i'll try "for the first time" and go into a heavy abuse --> addict stage. if that makes sense...
but hey, you never know.