Neighborhood green space and psychological distress: a longitudinal study of socioeconomic disparities in mental health outcomes.

Evidence suggests that neighborhood green space is associated with improvements in mental health. However, few studies have simultaneously considered both the risky and protective dimensions of green space in relation to psychological distress. Moreover, whether these spaces contribute to narrowing gaps in mental health problems across different social groups remains insufficiently understood. We aimed to examine the longitudinal association between neighborhood green space and psychological distress in adults, taking into account socioeconomic disparities. We used data from the Millennium Cohort Study (25,442 adult participants from the UK, 2003 to 2016) and applied mixed-effects models to assess the average longitudinal association between neighborhood green space exposure (measured as relative green space cover in deciles, comparing the highest and lowest deciles to the eight middle deciles) and psychological distress, adjusting for socioeconomic variables (poverty, education, ethnicity) and other potential confounders (age, sex, urbanicity, physical health, air pollution). Low green space exposure was associated with higher psychological distress. High green space exposure was consistently associated with lower psychological distress among socioeconomically disadvantaged individuals, with more robust and pronounced effects compared to wealthier groups. Overall, the lack of neighborhood green space may be more influential on psychological distress than its abundance, except for the most disadvantaged adults, for whom a high level of green space could be particularly beneficial. Fostering access to neighborhood green space may serve as a valuable strategy to reduce both environmental and mental health disparities.