Effects of shinrin-yoku (forest bathing) and nature therapy on mental health: A systematic review and meta-analysis

Abstract

Shinrin-yoku (forest-bathing), immersing oneself in nature using one's senses, has been receiving increased attention internationally. While most of the existing studies have focused on physical health, this systematic review and meta-analysis examined the mental health benefits of shinrin-yoku (i.e., depression, anxiety, anger), using the PRISMA guidelines (PROSPERO registery: BLINDED). Articles in English were retrieved on research databases including PubMed/MEDLINE, PsycINFO, Science Direct, and Google Scholar. Of 481 articles retrieved, twenty met the inclusion criteria (eight non-randomised and twelve randomised controlled trials). All studies were conducted in Asia and Europe and used a variety of different bathing approaches (e.g., breathing, walking, yoga). While noting a need for more rigorous research and more extensive follow-up assessments, the findings indicate that shinrin-yoku can be effective in reducing negative mental health symptoms in the short-term (large effects, g> .80); particularly, the effects on anxiety were largest. Overall, forest bathing improved depression, anxiety and anger in the short-term but there were a number of moderators of the effects. More careful examination of shinrin-yoku practices are needed; longer follow-up with participants from a range of countries along with greater examination of potential mechanisms of action are needed for shinrin-yoku to be accepted into mainstream interventions.