Living close to an urban greening program improved mental health in low-income city dwellers, according to results from a randomized trial, in which the greening intervention consisted of removing trash from vacant lots, grading the land, planting new grass and trees, installing wooden fences, and performing maintenance.
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Options for depression treatment are limited, and this has led researchers to consider environmental factors that might contribute to the condition. Vacant or dilapidated neighborhood spaces are a known factor for depression.
The researchers performed a citywide cluster randomized trial in Philadelphia, which included 541 vacant lots in 110 clusters. A total of 37 clusters were assigned to the greening intervention, 36 to the trash cleanup intervention, and 37 clusters were left alone. The researchers interviewed local residents near each cluster, using the short-form Kessler-6 Psychological Distress Scale to assess mental health outcomes, wrote Dr. South, of the University of Pennsylvania, Philadelphia.
The researchers interviewed 442 participants (mean age 44.6 years, 59.7% female) in the preintervention period, and 342 (77.4%) during the postintervention period. The researchers conducted a neighborhood poverty subset analysis that included 139 participants.
Intention-to-treat analyses showed that, compared with no intervention, those in the greening intervention experienced a significant decrease in reporting feeling depressed (–41.5%; 95% confidence interval, –63.6 to –5.9; P = .03) and feeling worthless (–50.9%; 95% CI, –74.7 to –4.7; P = .04). The investigators also found a trend toward a reduction in participants who self-reported being in poor mental health (–62.8%; 95% CI, –86.5 to –27.5; P = .051).
When the analysis was restricted to neighborhoods below the poverty line, the greening intervention led to a significant decrease in participants feeling depressed (–68.7%; 95% CI, –86.5 to –27.5; P =.007), but no statistically significant difference was found in participants with self-reported poor mental health.
The trash cleanup intervention had no significant associations with changes in mental health outcomes, compared with no intervention.
Dr. South reported having no disclosures. The study was funded by the National Institutes of Health, and the Centers for Disease Control and Prevention.
SOURCE: South EC et al. JAMA Network Open. 2018 Jul 20. doi: 10.1001/jamanetworkopen.2018.0298.