Genetic factors in substance abuse based on studies of Tourette syndrome and ADHD probands and relatives. II. Alcohol abuse.

Prior studies have suggested childhood attention deficit hyperactivity disorder (ADHD) as a risk factor for alcohol abuse in adults. Gilles de la Tourette Syndrome, a hereditary tic and impulse disorder, is clinically and genetically similar to ADHD. To examine the hypothesis that individuals carrying the Gts gene are at increased risk to develop alcohol use problems, the same TS (Tourette Syndrome) and ADHD probands, relatives and controls used in the prior study of drug abuse were also studied using a structured questionnaire based on the Diagnostic Interview Schedule and the MAST test. The frequency of a positive response to any of 16 different questions concerning alcohol abuse showed a highly significant increase with increased genetic loading for Gts and ADHD genes. The percentage of more than one positive response in TS probands was markedly influenced by the presence of comorbid ADHD, discipline, obsessive-compulsive or drug abuse problems. Comorbid drug abuse problems were the best predictor of alcohol abuse problems. These results suggest that the genes responsible for TS and ADHD play an important role in alcohol abuse/dependence as well as drug abuse/dependence. One of the elements common to all of these disorders may be mutant genes affecting serotonin metabolism.