Although the causal relationships among the genetic and environmental variables examined here are unknown, we note that early findings from genetically-informed randomized prevention studies suggest that efforts aimed at reducing environmental risk factors for adolescent alcohol use and related behavior problems may be particularly effective for those who are genetically predisposed toward developing such problems. For example, adolescents with either the short/short or short/long genotype of SCL6A4(5-HTT) who took part in a family-based prevention-intervention program aimed at increasing family cohesion were less likely to initiate risk behaviors (alcohol use, marijuana use, and sex) across a 29-month period compared to their counterparts in the control condition [49]. Examining whether efforts to bolster parental knowledge or reduce peer deviance attenuate polygenic risk for alcohol problems is an important direction for future research.
