Understanding the behavioral determinants of intervention fidelity in school mental health
Mental disorders are a leading cause of morbidity among children and adolescents worldwide, with Chile showing particularly high levels of stress, anxiety, and depression in students. Multi-Tiered Systems of Support (MTSS) offer a structured framework for school-based mental health interventions, yet sustaining fidelity remains challenging. This cross-sectional study analyzed how the COM-B model dimensions (capability, opportunity, and motivation) relate to intervention fidelity in Chilean public schools. Data were collected via surveys from 359 education professionals across all 16 regions, using an adapted DIBQ-18 and a composite fidelity index. Partial least squares structural equation modeling revealed psychological capability and reflective motivation as direct predictors of fidelity, while physical and social opportunities and automatic motivation exerted indirect effects through psychological capability. The model explained 33.2% of fidelity variance. Findings highlight the central role of individual-level determinants, suggesting that capacity-building strategies should prioritize enhancing competencies to strengthen school-based mental health interventions.