Alcohol consumption is associated with an interaction between DRD2 exon 8 A/A genotype and self-directedness in males.

Background: Both reduced postsynaptic dopamine D 2 receptor function and the character variable self-directedness (SDD) are related to the level of alcohol consumption. We examined for interactions between DRD2 exon 8 (rs6276), a polymorphism which has been associated with various alcohol-related phenotypes, SDD and alcohol consumption. Methods: A total of 144 male and 186 female probands with alcohol dependence or abuse diagnoses and without were included in the study. All subjects were assessed with the alcohol section of the Semi-Structured Assessment for the Genetics of Alcoholism and the Temperament and Character Inventory. Results: Male probands with A/A genotype reported significantly higher alcohol consumption in a typical week ( ANOVA; p = 0.024); those with A/A genotype and low SDD showed particularly high consumption levels (interaction DRD2 x SDD: p = 0.019). Alcohol dependence/abuse (DSM-IV) but not nicotine dependence was also relevant for higher alcohol consumption (trend: p = 0.052). In the female group, only alcohol disorders predicted alcohol consumption. Conclusions: Our findings support a role for a genepersonality interaction of DRD2 exon 8 x SDD in alcohol consumption in males. Copyright (c) 2007 S. Karger AG, Basel.