It is exceedingly rare that someone in Western society will have gone through their life without this being presented as a question. In fact, it is one of the more often debated subjects in addiction. It is clear that as a country we the United States have not given the mental health field the dedicated studying it deserves, and our rate of mental health issues and addiction correspond to this fact.
The question is: How does the fall into addiction happen to some and not to others?
Predisposition to alcoholism has been a much researched topic in both psychological and medical fields, and seems to be correlated somewhat to how much stress someone experiences as baseline. Most of this research that involves intervention has been performed on non-human models. A study performed in 1990 using rhesus monkeys showed that more anxious monkeys were predisposed to increased alcohol consumption. However, when stress was induced in the monkeys by separation, they would increase their intake to the same levels as the naturally anxious monkeys.