Implementation outcomes and strategies for depression interventions in low- and middle-income countries: a systematic review

BACKGROUND: We systematically reviewed implementation research targeting depression interventions in low- and middle-income countries (LMICs) to assess gaps in methodological coverage. METHODS: PubMed, CINAHL, PsycINFO, and EMBASE were searched for evaluations of depression interventions in LMICs reporting at least one implementation outcome published through March 2019. RESULTS: A total of 8714 studies were screened, 759 were assessed for eligibility, and 79 studies met inclusion criteria. Common implementation outcomes reported were acceptability (n = 50; 63.3%), feasibility (n = 28; 35.4%), and fidelity (n = 18; 22.8%). Only four studies (5.1%) reported adoption or penetration, and three (3.8%) reported sustainability. The Sub-Saharan Africa region (n = 29; 36.7%) had the most studies. The majority of studies (n = 59; 74.7%) reported outcomes for a depression intervention implemented in pilot researcher-controlled settings. Studies commonly focused on Hybrid Type-1 effectiveness-implementation designs (n = 53; 67.1), followed by Hybrid Type-3 (n = 16; 20.3%). Only 21 studies (26.6%) tested an implementation strategy, with the most common being revising professional roles (n = 10; 47.6%). The most common intervention modality was individual psychotherapy (n = 30; 38.0%). Common study designs were mixed methods (n = 27; 34.2%), quasi-experimental uncontrolled pre-post (n = 17; 21.5%), and individual randomized trials (n = 16; 20.3). CONCLUSIONS: Existing research has focused on early-stage implementation outcomes. Most studies have utilized Hybrid Type-1 designs, with the primary aim to test intervention effectiveness delivered in researcher-controlled settings. Future research should focus on testing and optimizing implementation strategies to promote scale-up of evidence-based depression interventions in routine care. These studies should use high-quality pragmatic designs and focus on later-stage implementation outcomes such as cost, penetration, and sustainability.