Identifying the active ingredients of a behavioral activation-based digital single-session intervention

Digital single-session interventions (SSIs) have been shown to be effective in reducing myriad mental health conditions. However, it is unclear which components of SSIs drive their therapeutic effects. In this study, we divided a well-evaluated behavioral activation-based SSI into three candidate components—PSYCHOEDUCATION, TESTIMONIALS, and ACTION PLAN—each hypothesized to have independent therapeutic value. We conducted a 23 factorial experiment (N=889) to evaluate effects of the individual components on depressive symptoms. Our results showed that only the ACTION PLAN candidate component had a significant effect on depressive symptoms at 2-week (d=−0.18) and 8-week (d=−0.12) follow-ups. Additionally, user’s perceptions of the intervention’s credibility and their expectations of improvement were significantly associated with a reduction in depressive symptoms at both time points. Our findings offer a more nuanced understanding of which elements within digital SSIs may drive their therapeutic benefits.