Overview of genetics and substance use disorders

A genetic component in etiology of substance dependence is very large, and the estimated hereditary rates by twin and family studies are 70% or more. Extensive classical linkage analyses for alcohol and substance dependence revealed numerous but weak susceptibility loci on every chromosomes. Genetic association studies including whole genome examination showed many shared genomic risks for substance dependence of diverse classes, e.g., alcohol, nicotine, opioids, cocaine, amphetamines and cannabinoids. In contrast, some specific genetic risks or protective factors for individual drug are also found. This paper reviews the current status of research into the genetics of substance dependence.