Is greenspace in the eye of the beholder? Exploring perceived and objective greenspace exposure effects on mental health

Abstract

Background: This study explores the relationship between greenspace and perceived stress, anxiety, and depression, and specifically how perceived and objective greenspace exposure relate to these outcomes. It also explores whether race and socioeconomic status (SES) influence perceived and objective greenspace exposure. Methods: We used structural equation models (SEMs) to assess the combined impacts of perceived greenspace (a latent construct that included greenspace abundance, visibility, access, usage, quality) and objective greenspace (NDVI within a 300-m buffer of residence) exposures on mental health outcomes (perceived stress, anxiety, and depression), adjusted for SES (using a latent variable that combined income, education, employment), race, ethnicity, age, and cohabiting status from a cross-sectional survey on greenspace and mental health in Denver, CO that ran from November 2019 to April 2021. We compared the strength of pathways between perceived and objective greenspace measures and mental health outcomes, as well as those between SES/race/ethnicity and greenspace measures. Results: Perceived greenspace exposure was directly associated with reduced anxiety; objective greenspace was only indirectly associated with reduced anxiety, through perceived greenspace. Perceived-but not objective-greenspace exposure was associated with lower depression with borderline statistical significance. SES was statistically significantly associated with higher objective greenspace (a direct impact) and perceived greenspace (direct impact and indirect impact mediated by objective greenspace), which suggests that some, but not all, of differential perceptions of greenspace exposure by SES are due to differential levels of objective greenspace exposure by SES. Conclusion: Our study shows that perceived greenspace exposure may be an integral part of how objective greenspace exposure confers mental health benefits, particularly anxiety. SES may also play a role not just in influencing objective greenspace exposure, but also in shaping peoples' perceptions of greenspace, which are unmeasured in most objective greenspace exposure measures.