Urban green space alone is not enough: A landscape analysis linking the spatial distribution of urban green space to mental health in the city of Chicago

Research on the association between urban green space and mental health has largely focused on the presence or quantity of green space, rather than on the spatial distribution of green spaces within the urban landscape. We therefore investigated the relationship between the amount, composition, and spatial distribution of urban green space and the level of psychological distress reported by residents of a large metropolitan city (Chicago, Illinois, USA). We used mental health data collected from 6405 residents in 61 communities by the Chicago Department of Public Health as part of their Healthy Chicago Survey, and quantified landscape metrics related to the amount and configuration of green space within these community 'landscapes'. Using generalized linear mixed models that controlled for socio-economic confounds, we found that residents reported less psychological distress within urban landscapes that had small-sized water bodies and greater distances between forested areas, which tend to characterize the distribution of large forest parks throughout Chicago. In terms of total green space, however, psychological distress levels were lower in landscapes having a disaggregated distribution of urban green spaces (i.e., many small green spaces) relative to a single (or a few) large green spaces. Our study thus highlights that the configuration of urban green space may be as important as the amount of green space to the mental health of urban residents.