JMIR Publications

ABSTRACT

Background:

In the digital era, mobile internet integration into daily routines presents a paradoxical relationship with mental health outcomes. While prior cross-sectional studies report inconsistent associations between mobile internet use (MIU) and depressive symptoms, the longitudinal mechanisms involving social support remain underexplored.

Objective:

This study aims to clarify the longitudinal relationships among mobile internet use (MIU), social support, and depressive symptoms in rural Chinese residents. Findings aim to inform digital health strategies that leverage online interactions to enhance mental well-being in underserved communities.

Methods:

A two-wave longitudinal cohort study (4-year interval) was conducted among rural residents in Taierzhuang District, China (N=489 retained). Multidimensional assessments included: 1) Demographic characteristics and MIU patterns via customized survey, 2) PSS using the PerceivedSocial Support Scale, and 3) Depression severity via CES-D. Advanced analytical strategies were implemented: LASSO regression for high-dimensional variable selection, complemented by cross-lagged panel modeling (CLPM) to disentangle temporal dependencies.

Results:

Our analysis found that the increase in mobile Internet use at baseline indicates the improvement of social support at follow-up (ρ=0.101, 95%Cl=0.092, 7.135). There is a bidirectional cross lagged relationship between social support and depression. An increase in baseline social support indicates a reduction in later depression (ρ=-0.096, 95%Cl=-0.142, -0.008). An increase in baseline depression indicates a decrease in later social support (ρ=-0.112, 95%Cl=-0.306 -0.011). And baseline social support has a significant impact on later depression. There was no direct effect between the two stages of mobile Internet use and depression.

Conclusions:

This study used longitudinal data and developed cross-lagged models to improve the reliability of causal inferences, and applied Lasso regression to improve the explanatory power and predictive accuracy of the models. The study reveals the complex impact of mobile internet use on mental health and emphasizes the importance of promoting healthy online social interactions. It is recommended that tools be developed to enhance real-life social connections and that individuals' online behavior patterns be considered in mental health interventions.