were coded as 0/1/2 to indicate the number of minor alleles present for a given individual. We did not control for alcohol dependence case status for our main analyses, because sensation seeking is substantially related to alcohol use behaviors (Zuckerman, 1994), and including it as a covariate may eliminate meaningful variance (Meehl, 1971). Nevertheless, post-hoc analyses revealed that our pattern of results and conclusions did not change if alcohol dependence was included as a covariate in the aggregated SNP tests (i.e. the p-value reported in Table 3 remained significant at p < 5 × 10−12).
