Implementation Fidelity and Mechanisms of Change in a Nonspecialist-Led Mental Health Intervention for Female Caregivers of Young Children in Rural China: A Qualitative Process Evaluation

Background
The Thinking Healthy Extended Program (THEP) is a nonspecialist-delivered mental health intervention targeting female caregivers (mothers and grandmothers) of children aged 6-36 months in rural China. It consists of 24 fortnightly group sessions, supplemented by individual home visits for caregivers who miss group sessions, and integrates cognitive reframing techniques, behavioral engagement, childrearing skills, and peer support. Embedded within a large-scale randomized controlled trial, this study aims to evaluate implementation fidelity of THEP, examine hypothesized mechanisms of change, and identify contextual factors, including enablers and barriers, that influenced intervention implementation.
 

Methods
In-depth interviews were conducted at 3 months and 10 months into the intervention implementation with 50 caregivers and 10 facilitators. The interview guides were developed based on the UK Medical Research Council’s process evaluation framework, with the facilitator interview guide focused on implementation fidelity, the caregiver interview guide focused on mechanisms of change, and contextual factors explored in both guides. All interviews were audio-recorded, transcribed, and analyzed using thematic analysis.
 

Results
THEP facilitators demonstrated competence in coordinating schedules, delivering sessions, and engaging caregivers. Caregivers reported improvements in peer support and childrearing skills, along with some uptake of behavioral engagement. However, both facilitators and caregivers demonstrated limited understanding of cognitive reframing techniques. Grandmothers (who accounted for 43% of the sample in the current study) experienced greater challenges than mothers with respect to applying the four program mechanisms of change. Several contextual factors, including a child-focused orientation, distractions related to the presence of children at sessions, and intergenerational differences between mother and grandmothers, influenced THEP implementation.
 

Conclusions
THEP was feasible to deliver through nonspecialist facilitators, but implementation quality was constrained by limited understanding of cognitive reframing strategies and variation in caregiver engagement. Future adaptation and scale-up should prioritize facilitator capacity and intervention approaches that are more feasible for nonspecialist providers and more accessible to diverse caregivers.