Mediating Role of Internet Use in Cognitive-Depressive Pathways: A Random Intercept Cross-Lagged Panel Modeling Approach

Objectives: Prior work has identified an inverse relationship between depression and cognition in older adults, but the mechanisms underlying this association remain unclear. This study investigated whether internet use mediates this relationship in middle-aged and older adults. Methods: Data were drawn from the China Health and Retirement Longitudinal Study (CHARLS) from 2015 to 2020 (n = 9,610). The Random Intercept Cross-Lagged Panel Model (RI-CLPM) with mediation analysis was used; subgroup analyses were conducted for middle-aged (45–64) and older (65+) adults. Results: At the between-person level, a significant negative correlation was found between cognitive function and depressive symptoms. Within-person analysis revealed a bidirectional relationship: poorer cognitive function predicted increased depressive symptoms (β* = −0.080, p < 0.001), and conversely, increased depressive symptoms predicted poorer cognitive function (β* = −0.019, p < 0.05). Internet use partially mediated this relationship, accounting for 8.58% and 9.69% of the total effects, respectively. This mediating effect was stronger in middle-aged adults than in older adults. Conclusion: These results emphasize the continued importance of exploring multidisciplinary interventions to mitigate depressive symptoms and delay cognitive decline in middle-aged and older adult populations.