I think the most likely explanation is that some sociopaths may also become alcoholics, but, judging from my own experience, not all alcoholics are sociopaths.
My AW has OCD, and displays some weird obsessive behaviors... like buying men's cologne by the case and hiding it in the closet. She has lied to cover up her drinking, but is selfish only in the fact that she's not willing to give up the alcohol, despite what it's doing to the family. Otherwise, she's generous to a fault.
She has been irresponsible with money, but never abusive or prone to rage.
I suppose it's possible that prolonged alcoholism could drive certain people toward sociopathic behaviors, but it seems likely that it would vary with each individual.