First implementation of a collaborative care model for common mental disorders in primary care in France: Fidelity of care manager intervention matters

Background Care for common mental disorders relies on primary care, where they often remain undiagnosed and untreated. The collaborative care model (CoCM) is a team-based approach involving care managers (CMs) who work alongside general practitioners and remote psychiatrists to provide evidence-based mental healthcare. Between 2021 and 2023, a pilot study implemented the CoCM for the first time in France in four primary care practices with nurses with previous professional experience in psychiatry acting as the CMs. As part of the implementation research of this pilot, we analyzed the fidelity of the CM intervention with the original CoCM, considering the CM process of care metrics and whether it followed a stepped-care approach, and its link with patients’ outcomes, which have rarely been addressed in previous international research on the CoCM. Methods Using electronic medical records, we calculated fidelity measures, including CM early intervention (time to first intervention), intensive care (number of visits and intervention duration), evidence-based care (type of care delivered), and variations according to initial symptom severity, in line with a stepped-care approach. Patient outcomes, particularly depression response and remission, were described according to initial symptom severity and fidelity measures. Results A total of 235 patients were included in the study. The care provided by CMs tended to match the original CoCM, in terms of early intervention, intensive care, and type of care delivered. It was adapted to the initial symptom severity, in particular for early intervention, in line with a stepped-care approach. Higher fidelity of the CM intervention to the CoCM, especially with respect to the time to treatment initiation and number of visits, was associated with better patient outcomes. Conclusions The CoCM shows promise for improving the treatment of common mental disorders in a stepped-care approach in French primary care. Its extension requires ensuring the fidelity of the CM intervention to the model in real-world settings, which appears crucial to achieving optimal patient outcomes and provides useful lessons for other countries implementing the CoCM. Trial registration number : not applicable