Mental Health, Schooling Attainment and Polygenic Scores: Are There Significant Gene-Environment Associations?

We estimate associations between a polygenic score (PGS) for depressive symptoms, schooling attainment and genetic-environmental (GxE) associations with depressive symptoms and depression for 29 years old in the National Longitudinal Study of Adolescent Health (Add Health) and 53 years old in the Wisconsin Longitudinal Study (WLS). We find some suggestive evidence that the association of the PGS with mental health is lower for more-schooled older individuals in the WLS, but no evidence in Add Health. Quantile regression estimates also show that in the WLS the GxE associations are statistically significant only in the upper parts of the conditional depressive symptoms score distribution. We assess the robustness of the OLS results to possible omitted variable bias by estimating sibling fixed-effect regressions. The sibling fixed-effect results must be qualified, in part due to low statistical power. However, they show that college education is associated with fewer depressive symptoms in both datasets.