Sustainment and sustainability of evidence-based treatment for post-traumatic stress disorder: findings from a post-implementation evaluation

Background Sustainment and sustainability of implemented complex evidence-based interventions in mental health settings remain an under-researched area of implementation science. Understanding what contributes to the ongoing use of evidence-based practices (EBPs) can inform all stages of implementation and help ensure effective treatment for patients. This study evaluated the sustainment of evidence-based practice for post-traumatic stress disorder in Norwegian mental healthcare 1, 2 or 3 years after the completion of a one-year implementation support provided to clinics between 2018 and 2022. The implementation support was based on the Leadership and Organizational Change for Implementation strategy (LOCI). Methods We measured implementation climate immediately after the implementation support period ended, and sustainment and organizational capacity for sustainability 1, 2 or 3 years after. We examined the relationship between organizational capacity for sustainability and implementation climate in relation to sustainment using mixed-effect modelling. Results Eleven out of 43 clinics (25.6%) reported sustainment to be in a great to very great extent and 26 clinics (60.5%) reported sustainment in the range of moderate to great extent. Organizational capacity for sustainability factors showed positive significant association with sustainment ( b = 0.46, 95% CI [0.38, 0.54], p < 0.001). Workflow Integration was significantly associated with sustainment ( b = 0.20, 95% CL [0.08, 031], p = 0.001) and Implementation and Training showed marginal ( b = 0.09, 95% CL [-0.00,0.19], p = 0.059) association with sustainment. Implementation climate was associated with sustainment only at 22 months post-implementation, but not at 35- and 40-months evaluation. Conclusions Focusing on practice fit and integration into existing routines and practices, in addition to securing ongoing education, training and supervision when building organizational capacity for sustainability may contribute to ongoing use of the EBPs. In addition, creating a positive implementation climate during the implementation phase might be important for the early stages of the sustainment phase. Trial registration The study was approved by Regional Committee for Medical and Health Research Ethics (REK; Id-number: 139026 and 775701). The study is preregistered in OSF DAM Registry with the registration DOI: https://doi.org/10.17605/OSF.IO/ABF43 . Clinical trial number: not applicable.