Adolescent depressive symptoms and memory performance in young adulthood: Testing critical period, accumulation, and pathway models using a sibling comparison design

Rationale: Despite the existing literature connecting depressive symptoms with cognitive function in adulthood, there is limited knowledge about the longitudinal association between depressive symptoms in adolescence and memory function in adulthood, as well as the mechanisms underlying this relationship. Objectives: This study aims to determine whether depressive symptoms in adolescence are associated with memory function in young adulthood. To explore the underlying mechanisms of this association, it employs a life course approach, testing the critical period, accumulation, and pathway models. Methods: Utilizing data from the sibling sample of the National Longitudinal Study of Adolescent to Adult Health (Add Health), this study employed sibling fixed effects models to control for unobserved heterogeneity at the family level. To test various life course models, the analysis incorporated adult depressive symptoms, as well as an array of behavioral, psychosocial, and educational mechanism variables. Results: Sibling fixed effects estimates indicated a longitudinal association between depressive symptoms in adolescence and memory function in young adulthood (b = -0.084, p < 0.01). Depressive symptoms in adulthood neither explained nor intensified this association. Mediation analysis revealed that educational attainment modestly accounted for about 11% of the relationship between adolescent depressive symptoms and adult memory function. Combined, these findings lend support to the life course approach, with a specific focus on the critical period model. Conclusions: This study's findings suggest that depressive symptoms in adolescence are an independent risk factor for memory function in adulthood. The empirical support for the critical period model underscores the importance of implementing early intervention programs and targeted strategies to support adolescents experiencing depressive symptoms.