One pooled analysisfound a significant negative association between 30% increase of green space in the neighborhood and depression (OR = 0.94), and a significant association between grade of urbanization (mean number of addresses per km2 within a radius of 1 km) and depression (OR = 1.05).

The other meta-analysis found a significant effect size (SMD = 0.30) for reduction of depressive mood after short-term exposure to natural environments.