I'm of the opinion that it doesn't really matter so much. I am an alcoholic, and the solution is the same no matter how I got here.
I am the only alcoholic in my entire family, none of my parents, grandparents or uncles/aunts nor my siblings are or were. I was also raised in what would likely be considered a "textbook" nuclear family. So I would seemingly have neither the hereditary nor environmental factors that would make me more likely to be an alcholic - yet I definitely am.