Cumulative Ecological Risk and Depressive Symptoms Among Chinese Junior high School Students: The Mediating Role of Defeat and the Moderating Role of OXTR Gene Rs2254298 Polymorphism

Objectives: Early adolescent depressive symptoms are closely related to their ecological environment. However, there is limited research examining the influence of multiple environmental factors on adolescent depressive symptoms and their psychological mechanisms. In addition, Adolescent depressive symptoms development is not only influenced by postnatal environmental factors but also by genetic factors. Thus it can be seen that the combination of environmental factors and genetic factors is helpful to further explain the internal mechanism of adolescent depressive symptoms.Methods: Based on the ecological systems theory, this study employed a gene-environment (G × E) research design using questionnaire surveys and DNA genotyping techniques, with 749 junior high school students as participants (Mage = 13.02, SD = 0.44). Multiple environmental variables were introduced to construct cumulative ecological risk, and an important gene locus (OXTR gene rs2254298) was included. A moderated mediation model was constructed to investigate the mechanism of adolescent depressive symptoms. Results: The results revealed that: (1) cumulative ecological risk significantly positively predicted adolescent depressive symptoms; (2) defeat mediated the influence of cumulative ecological risk on adolescent depressive symptoms; (3) the interaction between OXTR gene rs2254298 polymorphism and cumulative ecological risk significantly predicted defeat, and this interaction pattern conformed to the differential susceptibility model. Furthermore, carriers of the A allele were more sensitive to external ecological risks as compared to those carrying G/G homozygotes.Conclusions: This study provides a theoretical basis for the occurrence and intervention of adolescent depressive symptoms, and also verifies that the influence of gene and environment interaction on individual mental health conforms to different susceptibility models.