Economic evaluation of an online single-session intervention for depression in Kenyan adolescents.

Abstract
Objective: To evaluate the costs and cost-effectiveness of Shamiri-Digital, an online single-session intervention (SSI) for depression among Kenyan adolescents. Method: Data were drawn from a randomized clinical trial with n = 103 Kenyan high school students (64% female, M-age = 15.5). All students were eligible to participate, regardless of baseline depression symptomatology. We estimated delivery costs in 2020 U.S. dollars from multiple perspectives. To account for uncertainty, we performed sensitivity analyses with different cost assumptions and definitions of effectiveness. Using number needed to treat (NNT) estimates, we also evaluated the cost required to achieve a clinically meaningful reduction in depressive symptoms. Results: In the base-case (the most realistic cost estimate), it costs U.S. $3.57 per student to deliver Shamiri-Digital. Depending on the definition of clinically meaningful improvement, 7.1-9.7 students needed to receive the intervention for one student to experience a clinically meaningful improvement, which translated to a cost of U.S. $25.35 to U.S. $34.62 per student. Under a worst-case scenario (i.e., assuming the highest treatment cost and the strictest effectiveness definition), the cost to achieve clinically meaningful improvement was U.S. $92.05 per student. Conclusions: Shamiri-Digital is a low-cost intervention for reducing depression symptomatology. The public health benefit of empirically supported SSIs is especially important in low-income countries, where funding for mental health care is most limited. Future research can compare the cost-effectiveness of online SSIs to higher-cost treatments and estimate the robustness of Shamiri-Digital's effects over a longer time horizon.