Analysis of dopamine D2 receptor (DRD2) gene polymorphisms in cannabinoid addicts.

The gene encoding the dopamine D2 receptor (DRD2) has been suggested as a candidate gene for substance dependence. In this study, the possible association between Taq1A and Taq1B DRD2 polymorphisms and cannabinoid dependence was investigated. One hundred and twelve cannabinoid addicted and 130 healthy control subjects were included in this study. The Taq1A and Taq1B genotypes were determined in all subjects by polymerase chain reaction. For each polymorphism (A or B), the subjects were categorized into three groups according to their genotype, that is, the subjects with alleles A1/A1, A1/A2, A2/A2; B1/B1, B1/B2, and B2/B2. A significant association was found between Taq1A gene polymorphism and cannabinoid addicts compared to the control subjects. This finding suggests that polymorphism of the Taq1A, but not the Taq1B, may be associated with the susceptibility to cannabinoid dependence. Further clinical studies are required to be carried out for confirmation and evaluation of these findings.