I'm moving this dispute out of the comment box because it's not germane to the original topic. In my post on the aggressively eccentric Martin Sheen, I said "the 'root cause' of most poverty is bad morals: infidelity leading to divorce, illegitimacy, drug and alcohol addictions, etc."
Gordon Zaft strongly disagreed with my characterization of addictions, calling me a "fool." (Join the club! "Gordon Zaft" might be a pseudonym for one of my former teachers, or perhaps an ex-girlfriend.) Gordon elaborates in a subsequent comment:
Drug and alcohol addictions are most certainly NOT merely "bad morals" and it is, pardon me for saying so, unChristian to suggest that it is. It also does not square with a great deal of real research which shows real causes for addictive personalities. To deny them is, in fact, foolish.
If by "real" you mean that certain people are genetically predisposed to addictions, then you're right. The idea that certain weaknesses can be passed along to children is an insight that predates modern medicine by more than 2,000 years. Further, it wouldn't surprise me if the same studies confirmed that the level of predisposition varies from individual to individual.
The Catechism leaves no room for doubt that abusing drugs or alcohol is intrinsically sinful:
2290 The virtue of temperance disposes us to avoid every kind of excess: the abuse of food, alcohol, tobacco, or medicine....2291 The use of drugs inflicts very grave damage on human health and life. Their use, except on strictly therapeutic grounds, is a grave offense....
So there is a physical, genetic component to addictions, and a moral component. In some individuals, the physical component can be overwhelming, and the moral component minimal. In others, the opposite can be true. As addictions progress, the addict's will tends to become weaker and weaker, until the choice to take another drink or reach for the syringe is barely a choice at all.
I'm not a moral theologian. I don't even play one on the Web. But I can't really see how "bad morals" is an incorrect way to describe drug and alcohol abuse. I am not saying that addiction is exclusively a moral matter in every case, but unless someone is clinically insane and not responsible for his actions, then the addict must confront his own sinfulness and repent. It doesn't do him any good to explain away the addiction as merely genetic.
Gordon, maybe you could elaborate a little more about your objection. Perhaps I'm not understanding your point. Anyone else who wants to throw in their two cents (or if you're from Canada, two pesetas), please do so.