A person who knows he meets the D.S.M.-IV criteria for chemical abuse, and that abuse is often the precursor to dependency, and still continues to use drugs, is making a choice, and thus bears responsibility for it.
Basically he's saying what I think all of us here already know. Like with adult onset diabetes, the individual might be responsible for the initial unhealthy behaviors, but they most undoubtedly change the brains chemistry and then the disease takes over.
There's another aspect of responsibility not talked about here which is the responsibility the individual has to seek treatment. Just like with the diabetic, he must continue to avoid sweets if he wishes to avoid the downfalls of his disease, and as with the addict.
I wouldn't really say I learned anything new here, though.
And MattM, just curious why you "don't respect" philosophy. I mean, do you mean all of philosophy? Or just one area?