To illustrate the influence of all significantly associated SNPs on the total sensation seeking score, we calculated a “genetic risk score” (Evans, Visscher, & Wray, in press; Purcell et al., 2009; Wray, Goddard, & Visscher, 2007), defined for each individual as the sum of the number of minor alleles at each associated SNP multiplied by that SNPs regression weight from the aggregate SNP model. That is: (2)(SNP1 minor alleles,i.e.0/1/2*B1)+(SNP2 minor alleles*B2)+…+(SNP12 minor alleles*B12) Figure 1 illustrates the correlation (r = 0.20; p < 2 × 10−8) between this genetic risk score and the residualized total sensation seeking score1 (after accounting for age, sex, and ancestry; both the genetic risk score and the residual sensation seeking score were standardized to a mean of zero and a standard deviation of one to increase interpretability). With the caveat that calculating the genetic risk score in the same sample used to identify significant SNPs may represent an optimistic population effect size estimate, this correlation represents a non-trivial effect in the behavioral sciences (e.g. Cohen, 1992) and is notable in the context of the effect
