Results from MiXeR44 indicated that addiction risk was influenced by 16 202 (SE = 1833) SNPs and externalizing was influenced by 11 050 (SE = 159) SNPs. Externalizing shared approximately 81% of its influential variants with addiction risk whereas addiction risk shared 56% of its influential variants with externalizing (Figure 6). Within this shared component, the variants that influence both addiction risk and externalizing had high concordance of direction of effects (95%, SE = 0.05). The estimated genetic correlation between the two traits was 0.66 (SE = 0.01). Finally, model fit statistics supported a model in which addiction risk and externalizing modeled as distinct traits that share substantial polygenic overlap, rather than models in which there was complete or no polygenic overlap (Table S10).
