Yahoo! News - Gene Found for Obsessive-Compulsive Disorder
"They interviewed relatives of the patients and found 6 of the 7 people with the mutation had an obsessive-compulsive disorder, and some also had anorexia, Asperger's syndrome, which is a form of autism, social phobia or were abusers of alcohol."

I believe that alcoholism/addiction is going to be eventually categorized in the "obsessive-compulsive" family of mental disorders. (if it isn't already)