Although our genotypes contain useful information about our risk profile, genes influence behavior in complex ways. There are no genes “for” substance use disorder, depression, anxiety, or other complex behavioral outcomes. Our genetic codes impact the ways our brains are wired, contributing to differences in temperamental traits, the way we respond to risk and reward, our emotionality. These natural tendencies then impact our interactions with the world: the environments we seek out, the way we perceive our environments, the way the world responds to us (Scarr & McCartney, 1983). These processes are called gene-environment correlation, and they create feedback loops that accentuate genetic influence across time. Further, certain environments can constrain or exacerbate the influence of genetic predispositions, a phenomenon known as gene-environment interaction (Dick, 2011).
