Exploring uncharted territory: Do urban greenspaces support mental health in low- and middle-income countries?

Exposure to urban greenspaces promotes an array of mental health benefits. Understanding these benefits is of paramount importance, particularly in low- and middle-income countries (LMICs), where cities are expanding at an unprecedented rate. However, the existing evidence-base for the health benefits of greenspaces has a strong bias towards high-income countries. Here we systematically assess the emerging evidence regarding the mental health benefits provided by urban greenspaces in LMICs. We carried out a scoping review to assess the extent, type and quality of evidence investigating the relationship between greenspaces and mental health in LMICs. We systematically searched the literature databases Web of Science, Medline, Embase and CAB Abstracts using key terms related to greenspaces and mental health in LMICs. We analysed the resulting studies using a narrative synthesis approach, taking into account study quality, to assess the overall effects on mental health. 36 studies met the inclusion criteria and were included in the narrative synthesis. Studies were heterogeneous in design, study population, greenspace and mental health assessment. While more than 90% of LMICs remain unstudied, we found that eight out of ten studies using validated mental health screening tools detected positive associations between greenspaces and one or more mental health outcomes. These studies mostly took place in upper-middle-income countries. However, there still is a lack of evidence from regions with the highest levels of urbanisation, and only four studies assessed lower-middle and low-income countries. Furthermore, the analysis of mediating and moderating factors indicates that the relationship between greenspaces and mental health in LMICs is context dependent and needs to be assessed in relation to locally relevant environmental and cultural settings. Based on the evidence reviewed here, exposure to urban greenspaces can support multiple mental health outcomes in upper-middle-income countries. However, we still know little about poorer, rapidly urbanising countries. Our findings highlight the need for high-quality, context specific research in those urban areas with the highest levels of urbanisation, and the need to address specific challenges regarding mediating and moderating factors. Future studies should combine robust ecological assessments of greenspaces with validated mental health screening tools.