Drug abuse is a major public health burden with profound personal and societal consequences. Abuse of drugs is both common and heritable, with approximately 50% of the variability in the population being attributable to genetic factors.(Agrawal et al., 2012) Although heritability estimates vary somewhat by specific drug,(Verweij et al., 2010) twin studies suggest that common genetic pathways are likely shared across multiple drug categories, without excluding the possibility that other genetic factors influence the risk of abusing specific drugs.(Kendler et al., 2003; Tsuang et al., 2001)
