The interplay between polygenic susceptibility and discrimination on depressive symptoms: a prospective cohort study.

OBJECTIVES

This study investigated the interplay between perceived discrimination and polygenic propensity on depressive symptoms cross-sectionally and longitudinally.

METHOD: Data were from the English Longitudinal Study of Ageing (N = 4950). Perceived discrimination (2010-11) and depressive symptoms (CES-D, 2010-17) were assessed. Depressive symptoms polygenic scores (PGS) were calculated using summary statistics from the Social Science Genetic Association Consortium. Linear-mixed models were used to investigate associations.

RESULTS

Discrimination was perceived by 1869 (37.75%) participants. It was associated with greater baseline depressive symptoms (B = 0.631, 95% confidence interval(CI) 0.529,0.732, p < 0.001) though this difference decreased over time (B=-0.061, 95% CI -0.100,-0.022, p = 0.002). Those with higher depressive symptoms PGS had greater depressive symptomology at baseline (B = 0.136, 95% CI 0.089,0.184, p < 0.001) but this did not influence symptom trajectories (B=-0.003, 95% CI -0.021,0.015, p = 0.778). No significant interactions between discrimination and PGS were observed for baseline or later depressive symptoms, suggesting that the relationship between perceived discrimination and depressive symptoms was not moderated by genetic risk.

CONCLUSION

Perceived discrimination and depressive symptoms PGS were related to depressive symptomology. However, there was no interaction between these variables on depressive symptoms at baseline or longitudinally. This suggests that perceived discrimination and genetic risk operate independently to influence depressive symptomology.