Forest therapy is more effective in preventing or treating depression than alternative interventions

Rosa, C. D., Larson, L. R., Collado, S. ., & Profice, C. C. (2021). Forest therapy can prevent and treat depression: Evidence from meta-analyses. Urban Forestry &Amp; Urban Greening, 57. https://doi.org/http://dx.doi.org/10.1016/j.ufug.2020.126943

Research on the benefits of nature for humans suggests that forest-based activities may be especially helpful in producing positive health outcomes. While this body of research has focused on both physical and mental health, only a few studies have explored direct links between forest therapy and depression. To address this gap, researchers conducted an overview of systematic reviews (SRs) and meta-analyses to discern if forest therapy could be effective in preventing and treating depression.

For purposes of this study, forest therapy was defined as a combination of activities in a forest to improve one's health or wellbeing. Not included in this definition were forest exposure, forest exercise, and forest walking. From a search of the current literature, only four systematic reviews (SRs) focusing on the link between forest therapy and depression were identified. The research team analyzed all eligible primary studies (N=13) included in the four SRs. All 13 studies were conducted in the Republic of Korea, only one of which included children. A meta-analysis of the data involving 649 study participants focused on the forest therapy's capacity to reduce depressive symptoms as compared to no intervention/usual care and four alternative interventions (similar activities in a hospital, similar activities in an urban area, diet plus forest-based exercise, and walking in a forest).

Most of the interventions included in the studies ranged from a few days to a few weeks. No intervention lasted more than 11 weeks. The studies included seven different measures of depression. For this study, outcomes of interest included depressive symptoms, temporary recovery from depression, response to treatment, adherence to treatment, and adverse effects. Results showed that people experiencing forest therapy had a higher reduction in depressive symptoms than people experiencing no intervention or other forms of intervention. These results indicate that forest therapy is more effective in treating and/or preventing depression than participating in similar therapeutic activities in a hospital or in an urban (non-forested) area. ). Results also showed that when compared to no intervention/usual care, participants in the forest therapy group were 17 times as likely to experience remission and three times as likely to have at least a 50% reduction on depressive symptoms. The combined studies reported only one adverse effect -- a rash caused by an insect bite in the forest.

This research indicates that the effect of forest therapy on depression is greater than the effect of any alternative intervention. The findings suggest “that exposure to a forest environment may provide additional benefits beyond the therapeutic activities themselves.” Due to the fact that only one study involved young people, it remains unclear if forest therapy would be more or less effective in preventing or treating depression in children, adolescents, and young adults.

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