Initial Effect Size Estimation of a Smartwatch-based Intervention for Physical and Behavioral Activation in Depressed Patients

It is well known that physical activity interventions have a robust, if small-to-moderate effect on the amelioration of chronic diseases, including major depressive disorder (MDD) (Singh et al. 2023). At the same time, behavioral activation is one of the most effective components of digital cognitive-behavioral therapy for depression (Furakawa et al. 2021). Here we leveraged smartwatches to provide an interactive tool for delivering a mixed intervention of physical and behavioral activation, with the former addressing physical activity level and the latter pleasant activities including and beyond physical activity (e.g., social, relaxing activities). Moreover, given the relationship with physical activity level, we additionally incorporated digital insomnia exercises that have also shown promising effects in the amelioration of depression. Our primary aim was to estimate the effects of our digital smartwatch-based intervention in a small sample of depressed patients.