Fidelity and feasibility of a pilot implementation of adapted WHO digital interventions to scale up mental health in Nigerian primary care: A mixed-methods process evaluation

To address challenges in the real-world implementation of digital health for mental healthcare in Nigeria, this study conducted a process evaluation of five World Health Organization-recommended digital tools within a state-wide primary health care program in Lagos. Employing a convergent mixed-methods design across five facilities, we measured implementation fidelity through observation and platform analytics, and assessed stakeholder perceptions via validated surveys and interviews. The findings revealed a sharp divergence in success. Administrative tools that streamlined workflows, such as drug stock notification and automated client reminders, achieved high fidelity (>90% adherence). In contrast, clinical tools that altered provider-patient interactions, including a decision support app and a client helpline, demonstrated low fidelity (