Beyond access: usage variety, instrumental support, and later-life depression in a prospective study of Chinese older adults

Abstract

Introduction The digital divide is treated as a social determinant of later-life mental health, yet most evidence is cross-sectional and cannot separate its prospective effect from contemporaneous confounding. We examined which facets prospectively predict depression in older adults, and through what pathway. Methods We analyzed three waves (2018, 2020, 2023) of the China Longitudinal Aging Social Survey. Four 2020 divide indicators (access, proficiency, usage variety, outcomes) predicted 2023 CES-D-9 symptoms, adjusting for baseline symptoms and covariates; the 2018–2020 interval provided an earlier-window replication. Half-longitudinal (Cole-Maxwell) mediation tested four social-connection mediators, moderated by hukou, living arrangement, and gender. Results After adjustment for baseline depression, only the usage-variety divide—a narrower range of online activity—predicted higher subsequent depressive symptoms (b = 0.069, 95% CI 0.008–0.131). Of four mediators, only instrumental support mediated this association (indirect 0.019, bootstrap 95% CI 0.010–0.033), replicating in the 2018–2020 window (indirect 0.014, bias-corrected 95% CI 0.005–0.028). The pathway was stronger among urban and co-resident adults, with baseline instrumental support far higher in urban than rural areas (difference 0.82, p < 0.001), consistent with resource multiplication rather than substitution. Discussion Conditioning on baseline depression, only the usage-variety divide—not access, proficiency, or outcomes—is prospectively associated with later depressive symptoms (chiefly as a stable between-person difference); this association was statistically mediated by lower instrumental support. Because the mediated association was stronger in resource-rich subgroups, the pattern is more consistent with resource multiplication than with substitution. Translating digital inclusion into mental-health gains may require broadening use while strengthening instrumental-support infrastructure, especially in rural settings.