Abstract
BACKGROUND: The association between internet use and the mental health of older adults presents a complex research issue with inconsistent findings. While potential mechanisms have been explored, the integrated examination of socio-cognitive and health-behavioral pathways, particularly the chained mediation effect, remains understudied. METHODS: Utilizing cross-sectional data from the 2023 China General Social Survey (CGSS), this study analyzed a sample of 3,206 adults aged 60 and above. Mental health was operationalized using a single-item measure of the frequency of depressive moods. A structural equation model (SEM) was employed to explore the parallel and chained mediating roles of perceived social justice and physical activity in the relationship between internet use and mental health. It should be acknowledged that these mediation analyses are statistical and exploratory in nature, and do not establish temporal or causal ordering. Robustness checks were conducted using propensity score matching (PSM). RESULTS: Internet use was significantly and directly associated with better mental health (β = 0.098, p < 0.001). Parallel mediation analysis revealed two significant but opposing indirect paths: a negative indirect effect through reduced perceived social justice (β = -0.017, p < 0.001) and a positive indirect effect through increased physical activity (β = 0.027, p < 0.001). Crucially, a significant chained mediation pathway was identified: internet use → lower perceived social justice → reduced physical activity → poorer mental health (β = -0.018, p < 0.001). Multi-group analysis confirmed significant gender differences in these mediating pathways. CONCLUSION: Internet use is associated with older adults' mental health through a complex mechanism involving both a direct positive association and indirect pathways via perceived social justice and physical activity. The verified chained mediation effect suggests a potential "cognition-behavior" transmission pathway. A key limitation of this study is its cross-sectional design, which precludes causal inference. These findings highlight the dual-edged nature of internet use, suggesting that public health initiatives aimed at promoting digital inclusion for aging populations could concurrently foster a positive online information environment, enhance digital literacy, and encourage physical activity to maximize benefits and mitigate risks.