Longitudinal Mediating Mechanisms of Family Cohesion on Adolescent Internalizing and Externalizing Problems: The Differentiated Role of Parental Depression

INTRODUCTION: The present study systematically examined the dynamic relationships among family cohesion, parental depression, and adolescent internalizing/externalizing problems, with the aim of disentangling their interactive mechanisms and comparing heterogeneous family process patterns across problem types. METHODS: = 16.26 years) and their primary caregivers (60.20% mothers) from Liaoning Province. Data were collected across three waves (June 2024, December 2024, and June 2025) using validated measures. Bivariate and trivariate cross-lagged panel models were constructed, and indirect effects were tested using bootstrap confidence intervals. RESULTS: First, parental depression and adolescent internalizing problems exhibited symmetric bidirectional associations, whereas the relationship with externalizing problems was asymmetric, with child-driven effects significantly outweighing parent effects. Second, family cohesion demonstrated symmetric reciprocity with internalizing problems, but a family-effect-dominant asymmetry with externalizing problems. Third, parental depression mediated cohesion's protective effect on internalizing problems. Indirect effects were significant for depression (95% CI [-0.088, -0.008]) and anxiety (95% CI [-0.101, -0.005]), but not for externalizing problems (95% CI [-0.399, 0.063]). Additionally, adolescent problem behaviors eroded family cohesion by exacerbating parental depression, forming a vicious cycle. CONCLUSIONS: These findings underscore the type-specific nature of family dynamics and the conditional role of parental depression as a differentiated mediating channel. Parental depression selectively transmits cohesion's protective effects to internalizing problems only, while adolescent problem behaviors reciprocally erode cohesion by exacerbating parental depression. These findings advance understanding of family processes within collectivist systems.