Polymorphisms in the DBH and DRD2 gene regions and smoking behavior.

The DRD2 TaqI A and DBH-1021 C/T polymorphisms were genotyped in smoking alcoholics (N = 100), non-alcoholic smokers (N = 120) and nonsmoking controls (N = 112). Alcoholic and non-alcoholic smokers presented a higher frequency of the DRD2 TaqI A1 allele (P = 0.04) than non-smoking controls. Individuals who had at least one DBH-1021 T allele smoked fewer cigarettes per day than CC homozygotes (P = 0.03). These results are coherent with the expected effects of these polymorphisms on dopaminergic function.