parallel literature has also linked relative hypoactivity of the VS to drug-seeking behaviors, which has often been theorized to reflect compensation for blunted reactivity to reward71,75. Thus, it is plausible that blunted VS reward response associated with rs75168521 may confer susceptibility to extreme and generalized forms of drug dependence. On the other hand, the finding for rs1890881 might typify individuals at high neurobiological susceptibility for substance use engagement, particularly with alcohol which is easily accessible and socially accepted. Given the heterogeneity of substance use-related phenotypes, it is plausible that different genetic risk markers may impact disease risk through distinct mechanisms, and that these seemingly divergent theoretical models (e.g., impulsivity vs reward deficiency) may not be mutually exclusive.
