If modern medicine, psychiatry, and psychology have taught us anything it is that addiction DOES change people physiologically and mentally.
To assume that all the rants of an acute alcoholic or drug addict truly refelect their rational thoughts is absurd. I have personally known some people before, during, and after such addictions. To even suggest that they, in their most depraved state, are revealing their true nature and true hidden thoughts is wrong. This can be verified from human experience.
They reflect his thoughts, rational or otherwise. He is responsible for what he says, does and thinks, drugged or sober.