Thus for SUD, which is so clearly influenced by social phenomena, two pathways exist from genes to trait. First is the traditional ‘inside the skin’ pathway typically considered by molecular biology (whereby gene variants influence how the drug is absorbed and interacts with receptors and second messengers, as well as hedonic and motivational pathways). Second is an ‘outside the skin’ pathway, as we illustrated for peer deviance, whereby genetically mediated personality traits affect the degree to which the individual selects themselves into drug-predisposing or protective social environments.
