The impact of digital infrastructure construction on the depressive symptoms among middle-aged and older adults: evidence from China

The “Broadband China” strategy has enhanced digital infrastructure through urban fiber upgrades, rural broadband expansion, and improved network performance. This research employs the multi-period difference-in-differences (DID) model using 2011–2020 CHARLS data to explore underlying mechanisms. Findings indicate digital infrastructure reduces depression, mediated primarily by strengthened old-age services and social well-being. Heterogeneity analysis reveals stronger effects among urban residents, individuals aged 45–60, and those with higher cognitive abilities. By demonstrating the mental health benefits of digital infrastructure through the “Broadband China” case, this study provides empirical evidence for developing nations to leverage technological investments for public health objectives, particularly in aging populations. The results underscore the importance of integrating digital development with social support systems to maximize health outcomes.