Comparison of surf and hike therapy for active duty service members with major depressive disorder: Study protocol for a randomized controlled trial of novel interventions in a naturalistic setting.

Many active duty service members suffer from major depressive disorder (MDD). Although traditional treatments exist, alternative approaches may also be effective in treating depressive symptoms. Previous research has shown that physical activity has significant positive effects on depression symptoms in individuals with MDD, and that these benefits may be enhanced when physical activity occurs in a natural environment. Even though physical activity (i.e., hiking, walking) in natural environments has been shown to reduce depressive symptoms, water-based activity occurring in a natural environment (e.g., surfing) may produce even greater improvements in depressive symptoms. We detail an ongoing randomized controlled trial (RCT) comparing the efficacy of surf therapy and hike therapy with respect to immediate and longer-term psychological, physical, and functional outcomes in active duty service members with MDD. We describe the methodological development of this RCT evaluating novel treatment approaches and discuss considerations for evaluating physical activity interventions in a naturalistic setting.