Gene-environment interplay can also occur in the form of gene-environment interaction (GxE). That is, environmental factors may buffer or exacerbate the association between genetic factors and developmental outcomes (Plomin et al., 1977). There is evidence that social support moderate genetic influences on alcohol use outcome. For example, using a sample of young adults in the Finnish Twin Study, Barr et al. (2017) found that higher levels of social support were associated with increased genetic influence on alcohol misuse for females and reduced genetic influence for males. Support from parents was found to mitigate the genetic risk effect of the serotonin transporter gene (5-HTTLPR) on developmental trajectories of alcohol use from adolescence to young adulthood in a nationally representative sample (Su et al., 2019). Together, these studies indicate that social support buffers genetic risk in relation to alcohol use and also suggest the need to examine potential sex differences in the role of social support. Given that sensation seeking is a genetically influenced trait related to increased risk for alcohol use, it is also possible that social support also buffers the relation between sensation seeking and alcohol use; however, to our knowledge, no study has tested this hypothesis.
