The greening of vacant urban lots significantly reduced feelings of depression and worthlessness

South, E. ., Hohl, B. ., Kondo, M. ., MacDonald, J. ., & Branas, C. . (2018). Effect of greening vacant land on mental health of community-dwelling adults: A cluster randomized trial. JAMA Network Open, 1. https://doi.org/http://dx.doi.org/10.1001/jamanetworkopen.2018.0298

The idea that the physical conditions of a neighborhood can influence the mental health status of residents is well-supported by research. This study builds on that research by asking, “Does the greening of vacant urban land reduce self-reported poor mental health in community-dwelling adults?"

Researchers used city records to obtain a master list of all the vacant lots in Philadelphia, Pennsylvania. After excluding lots that were (a) “not sufficiently blighted,” (b) were paved parking lots, or (c) were larger than 5500 square feet, the researchers generated a second list as potential study lots. The blight status of lots was based on whether or not they had existing violations reflecting blight (illegal dumping, abandoned vehicles, and/or unmanaged vegetation) and were abandoned. From the list of potential study lots, 541 were grouped into 110 “clusters” within four sections of the city and randomly assigned to 1 of 3 study groups of adults living within the cluster areas. For one study group (the control group), no changes were made to the vacant lots.  Changes made for a second group (the “greened vacant lot” group) included removing trash, grading the land, planting grass and trees, installing a wooden fence, and performing regular maintenance. Changes for a third group (the “trash cleanup” group) involved removing trash, planting some grass, and performing regular maintenance. Data analyzed for this study included a self-report mental health assessment completed by 342 adults before changes were made to the vacant lots and 18 months after changes to the lots. This assessment was based on the short version of the Kessler-Psychological Distress Scale, which included items relating to feelings of nervousness, helplessness, restlessness, worthlessness, and depression.

Self-report mental health scores for the adults living near greened vacant lots showed a significant decrease in feelings of depression and worthlessness and a nonsignificant reduction in self-reported mental health.  Similar results were not reported by the other two groups.

Findings from this study - the first experimental study of vacant lot greening - show that adding greenspace to a neighborhood environment can improve the mental health status of residents.  These findings highlight the potential of vacant lot greening as an effective public health intervention for addressing mental health problems in low-income urban settings.

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