I just read a post in the twelve step forum about how after a certain point the A is powerless to stop. I can see that, I mean if you feel like crap all the time, no one wants to be around you, etc., if you could choose to stop wouldn't you?
Just my thought on the matter but I think if everyone I cared about started treating me like a train wreck because of something I was doing then I would stop doing it if I had the choice to.