The Quest of Candidate Gene in Alcohol Dependence: The Dopamine D2 Receptor (DRD2) Gene

The cause of alcoholism has been hypothesized as a highly heterogeneous genetic load. Family, twin, and adoption studies suggest a strong genetic component in alcohol dependence. The role of the dopamine D2 receptor (DRD2) gene in the development of alcohol dependence is controversial. The controversy is due in part to the definitions of subtypes in alcohol dependence. Since 1960, many reports have used biopsychosocial approaches to subtype alcoholism; however, no subtypes have been genetically validated. Four subtypes of alcoholism using comorbidity of alcoholism have been reported: pure alcoholism, anxiety/depression alcoholism, antisocial alcoholism, and bipolar disorder with alcoholism. This chapter reviews recent studies of association of the DRD2 gene with alcoholism subtypes in order to enlighten the inconsistent results of the DRD2 gene with unsubtyped alcoholism.