In conclusion, the findings presented here help elucidate the mechanism of transmission from the 5-HTTLPR S allele to a variety of alcohol-related outcomes. That is, adolescents with the S allele may be at greater physiological risk to engage in detrimental substance use behaviors by way of lower sensitivity to the effects of consuming alcohol. However, our findings also demonstrate that this risk is not deterministic, and that adaptive social supports, such as parental monitoring, may minimize effects of these innate risk factors. Alternatively, under the view of differential susceptibility, those with the S allele, which leads to lower sensitivity to alcohol, may be especially vulnerable to environmental influences (e.g., parental monitoring), both for the better and for the worse. Intervention programs that emphasize increasing parental monitoring and knowledge of their child’s whereabouts and affiliations are likely to have a profound impact on youth at high risk for alcohol problems based on genetic and physiological factors.
