I try not to think about it :-) I think you can find as many opinions as to the root causes of alcoholism as you can find behavioral scientists, physicians, therapists, counselours, etc. I try to avoid dwelling on the "nature vs. nurture" argument because subscribing to either side would allow me to justify my drinking. If I come to believe it's the way God made me, and "I was born this way," then there's no reason I shouldn't drink. If I come to believe that it's purely behavioral, then I should be able to quit any time I want.
I've found my relief in considering it a spiritual matter and dealing with it in those terms.