Dopaminergic Genetic Variation in Young Adolescents: Associations with Sensation-Seeking.

Deficient reward functioning, including reward-related personality, is implicated in depression's etiology. A dopaminergic genetic multilocus genetic profile score (MGPS) has previously been associated with neural reward responsivity but, despite theoretical basis, has not been studied with reward-related personality. Such research is needed to elucidate associations between genetic variation and reward-related personality in a developmentally sensitive population. In the present study, we examined associations between dopaminergic MGPS's and self-report reward-related personality in two young adolescent samples aged 10-15 years old (Sample 1: N = 100 girls, 82% White, 18% Other; Sample 2: N = 141, 65 girls, 76 boys, 89.36% White, 10.64% Other) using an established MGPS and an augmented MGPS. A "mini" meta-analysis synthesized results across samples. In Sample 1, an exploratory mediation analysis intended to gauge effect size for future work tested a path between the MGPS and depression through significant reward traits. In each independent sample, both MGPS's showed significant associations with sensation-seeking but not social drive, a pattern that persisted following correction. Effect sizes of novel variants were at least as robust as established variants, suggesting their added utility. Additionally, the exploratory mediation analysis suggested no noteworthy indirect effect, but a small (R2 = 0.022), statistically non-significant direct effect of the MGPS predicting prospective depressive symptoms. Results suggest that dopaminergic genetic variation is associated with the reward-related personality trait of sensation seeking but not social drive. Additional work is needed to probe whether sensation seeking may be a path through which this genetic variation confers depression risk.