Effects of polygenic risk score, childhood trauma and resilience on depressive symptoms in Chinese adolescents in a three-year cohort study

•Polygenic risk score (PRS) is a method of revealing multiple genes effects.•Childhood trauma, PRS and resilience were associated with adolescent depressive symptoms.•Resilience protectively mediates the relationship between emotional abuse, emotional neglect, physical neglect and depressive symptoms.•Resilience could moderate the associations between emotional abuse, physical neglect and depressive symptoms. Polygenic risk score (PRS) is a method of revealing multiple genes effect. The study of PRS and childhood trauma (CT) and resilience on adolescent depressive symptoms are fewer reported, especially the functional mechanism of resilience among them. 718 Chinese adolescents aged 10-14 years were surveyed including CT, resilience, depressive symptoms, and phenotype data in three years of the cohort study. PRS was calculated by the weighted accumulation effects of alleles on depressive symptoms. Their relationships were analyzed by the mediation and moderation models. PRS and CT were risk factors for depressive symptoms. Interaction (PRS × CT) on depressive symptoms had no statistical significance. Resilience acted as the protective mediator from CT (emotional abuse, emotional neglect, physical neglect) to depressive symptoms and moderator from CT (emotional abuse) to depressive symptoms. The sample size was a little small so that the inference were drawn prudently. Except gene data, other were collected by self-reported questionnaire instruments which inevitably brought recall bias. PRS and CT could have adverse impact on depressive symptoms, resilience could alleviate these risk effects as a moderator and a mediator. The findings have important implications for prevention and intervention in adolescent depressive symptoms.