Surf therapy for people with mental health disorders: a systematic review of randomized and non-randomized controlled trials

Background: Surf therapy is gaining popularity for improving mental health. However, there is limited research evidence to substantiate these claims. Therefore, this systematic review aimed to assess randomized or non-randomized studies analyzing the efficacy of surf therapy in improving symptoms of mental illness compared to non-exercising controls and/or alternative intervention, and to identify evidential gaps to inform future research. Methods: PRISMA 2020 reporting guidelines were followed. Eligibility criteria included participants of any age and sex, explicitly diagnosed with any mental health disorder, while exposed to surf therapy and compared to non-exercising controls and/or alternative interventions. The primary outcome consisted of changes in symptoms of mental illness scored from baseline to post-intervention. Any randomized or non-randomized trial design was considered. We searched Cochrane Library, CINAHL, EMBASE, PubMed, Scopus, SPORTDiscus and Web of Science databases (December 7, 2023), without language or publication date restrictions and without filters. Risk of bias was assessed using RoB 2. A meta-analysis could not be conducted due to heterogeneity of the studies; therefore, a narrative synthesis of individual study results was performed. Results: Of 5,666 records, three randomized controlled studies were included in the review. Overall, the findings of the three studies suggest no robust consistent evidence of improvement in mental health symptoms when comparing surf therapy to wait-list control groups or other nature-based exercise interventions (hike therapy). Certainty of evidence should be considered very low, as it is based on three randomized controlled trials. Conclusion: Although we believe that surf therapy provides an interesting approach, robust evidence is scarce. Routes for future well-designed, controlled studies are discussed. Other: No funding to report. Registration: PROSPERO CRD42021277060.