With mounting evidence for involvement of GABRA2 and CHRM2 in alcohol problems and related externalizing disorders, we aimed to further explore the risk associated with these genes in a general, population-based sample. To that end, we genotyped associated markers across both genes in the Child Development Project (CDP), an intensively studied community-based cohort of more than 500 children, followed annually from kindergarten through their mid-twenties. In 2006 and 2007 we collected DNA from the participants via saliva sample and obtained DNA from 452 individuals, representing 93% of the target sample of regular CDP participants. Based on the twin literature indicating that childhood behavior problems and adult alcohol dependence overlap largely due to shared genetic factors (Slutske et al., 1998), and that alcohol dependence symptoms observed very early in adolescence have a very different etiology, being largely environmentally influenced (Rose et al., 2004), we hypothesized that genes originally associated with adult alcohol dependence would be associated with behavior problems at earlier stages of development. We also hypothesized that the association between the gene and behavior problems would be moderated by environmental
