While I abused many substances back in the day, alcohol was always my drug of choice (easy to get & socially acceptable - in moderation, that is. ). My family tree is full of alcoholics, which makes me think that, in my case, it's an illness/disease. There's a pretty sound theory that suggests alcoholics' livers metabolize alcohol differently than those of normal drinkers. Thus, IMO, heredity has a lot to do with my disease of alcoholism. That said, UpDownAround's contention that it's a predisposition probably holds true for many people, too.