the behavioral disinhibition dimension. Second, in studies that have found significant SNP associations with smoking, the sample size has been substantially larger than the size of the sample in this study. For example, the ENGAGE consortium includes more than 30,000 genotyped participants for each of their smoking phenotypes (Thorgeirsson et al., 2010). While we were unable here to detect the effect of individual SNP associations, we are able to detect the aggregate effect of multiple SNPs. Specifically, in a previous analysis with a subset of the sample used here, we found a significant association of smoking (in current smokers) with an aggregated score based on 92 SNPs identified in a previous meta-analysis of smoking (Vrieze, McGue, & Iacono, 2012).
