Complex Interventions and Interorganisational Relationships: Examining Core Implementation Components of Assertive Community Treatment

Introduction: There is increasing interest in implementing evidence-based integrated models of care in community-based mental health service systems. Assertive Community Treatment (ACT) is seen as an attractive, and at the same time challenging, model to implement in sectored service settings. This study investigates the implementation process of such an initiative.Methods: Interviews were conducted with ACT team members, the process leader, steering group members, and collaboration partners. The “Sustainable Implementation Scale” helped to identify critical implementation components, and these were further explored using the qualitative interview data. The “Tool for Measuring Assertive Community Treatment” addressed programme fidelity, and the initiative’s sustainability was assessed.Results: High-fidelity implementation of ACT in a sectored service setting is possible. Prominent components that facilitated implementation were careful preparations, team members’ characteristics, and efforts by the process leader and the steering group to improve networking. Implementation was hampered by conflicting goals among the involved authorities and a mismatch between the ACT model’s characteristics and existing organisational traditions and regulations.Discussion and Conclusions: Reducing the uncertainty caused by conflicting goals is an important step in improving the implementation of ACT. In order to facilitate implementation, the goals, regulations, and availability of resources should be aligned horizontally and vertically through the involved organisations