Dopamine D2 (DAD2) and dopamine D3 (DAD3) receptor gene polymorphisms and treatment outcome in alcohol dependence

The dopaminergic system is critically involved in reward mechanisms mediating the reinforcing effects of alcohol. The intention of this study was to investigate the genotypic frequencies of the -141C Ins/Del polymorphism of the DAD2 receptor gene as well as the Bal I polymorphism of the DAD3 receptor and their potential association with treatment outcome in alcoholism. Therefore, individuals suffering from primary alcohol dependence were clinically and genetically characterized and followed prospectively over a period of one year after inpatient treatment. No association was found between DAD2 or DAD3 receptor gene variants and treatment outcome as reflected by abstinence/relapse after one year. Taking into account potential stratification effects, such as family history, gender, age of onset, or severity of the disease an association with DAD2 or DAD3 gene variants could neither be found. In conclusion, we found no evidence that the DAD2 or DAD3 gene variants investigated have a major influence on treatment outcome in primary alcohol dependence.