Genetic influences on addiction

Addictive disorders are prevalent in many populations, influenced by genetic and environmental factors, and moderately to highly heritable. Often, addictions to different substances co-occur, and evidence from twin studies suggests that this is due, at least in part, to a common underlying genetic etiology. Techniques for gene discovery include linkage analysis, association studies of candidate genes, and genome-wide association tests. These approaches have enabled the identification of genes influencing addiction to alcohol, nicotine, and illicit substances. This article reviews recent findings of genetic loci affecting susceptibility to substance addictions. Contributions to our understanding of liability and treatment from the field of pharmacogenetics are also considered. Finally, the clinical relevance of the current state of addiction genetics is discussed.