Stressful life events and adolescent drug use: Moderating influences of the MAOA gene

Purpose: Though stressful life events appear to impact the likelihood and frequency of substance use among adolescents, these effects are often varied and inconsistent. We suggest that the polymorphic MAOA gene may be partially responsible for variable susceptibility to environmental pressures and substance use. More specifically, we hypothesize that adolescents possessing low activity alleles for the MAOA genotype are more likely to respond to stressful life experiences by initiating substance use. Methods: The genetic subsample of the National Longitudinal Study of Adolescent Health was analyzed (2,574 adolescents) using logistic regression models for each gender. Respondents' self-reports of eight key stressors were used to create a composite life stress scale which was allowed to interact with a variable that represented the number of low activity MAOA alleles. Results: For males, a significant interaction emerged between stressful life experiences and the MAOA gene for alcohol (p = .029) and marijuana (p = .039) initiation. For females, the interaction was not significant in each model. Conclusions: MAOA interacts with life stress to increase the likelihood of substance use initiation for males. Those with a low activity MAOA allele are more likely to initiate substance use than those with a high activity allele when exposed to stressful experiences. (C) 2013 Elsevier Ltd. All rights reserved.