Genetic pre-determinants of concurrent alcohol and opioid dependence: a critical review

Concurrent alcohol dependence poses a significant burden to health and wellbeing of people with established opioid dependence. Although previous research indicates that both genetic and environmental risk factors contribute to the development of drug or alcohol dependence, the role of genetic determinants in development of concurrent alcohol and opioid dependence has not been scrutinised. To search for genetic pre-determinants of concurrent alcohol and opioid dependence, electronic literature searches were completed using MEDLINE (PubMed) and EBSCO (Academic Search Complete) databases. Reference lists of included studies were also searched. In this discussion paper, we provide an overview of the genes (n=33) which are associated with the opioid, serotonergic, dopaminergic, GABA-ergic, cannabinoid, and metabolic systems for each dependency (i.e., alcohol or opioid) separately. The current evidence base is inconclusive regarding an exclusively genetic pre-determinant of concurrent alcohol and opioid dependence. Further search strategies and original research are needed to determine the genetic basis for concurrent alcohol and opioid dependency.