Project Summary/Abstract Too many patients do not receive evidence-based treatments (EBTs) for mental health problems. In response, implementation science has rapidly advanced to bring EBTs to routine practice settings, and thereby improve patient outcomes. Unfortunately, research on sustainability of EBTs remains alarmingly limited. This is concerning, given that EBT activities and benefits regularly decline post-implementation. To prevent these declines, research on sustainability is urgently needed. Per NIMH’s Strategic Plan 4.2, this F32 will advance research on sustainability – namely, sustainability (a) outcomes, (b) predictors, and (c) mechanisms – by leveraging an ongoing, parent R01 (R01MH120147). The R01 focuses on implementation of an EBT in 10 of California’s community mental health centers (CMHCs). Specifically, the CMHCs partnered with the R01 team to implement the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C) for individuals with serious mental illness. Additionally, the R01 was designed to test whether manipulating TranS-C to “fit” the CMHC context would improve implementation outcomes by randomizing CMHCs to deliver Standard TranS-C or Adapted TranS-C. Thus, the R01’s infrastructure allows this F32 to test three primary aims. Consistent with Shediac-Rizkallah and Bone’s sustainability framework, Aim 1 will evaluate qualitative and quantitative sustainability outcomes of TranS-C, with respect to continued (a) activities, (b) benefits, and (c) capacity. Aim 2 will use hierarchical linear modeling to evaluate whether manipulating treatment fit to context predicts sustainability outcomes. Aim 3 will use structural equation modeling to test possible mediators – specifically, provider perceptions of fit (i.e., acceptability, appropriateness, and feasibility) – of the relation between manipulated treatment fit and sustainability outcomes. To accomplish these aims, the applicant will receive training in: (1) sustainability of EBTs, (2) advanced quantitative analysis, (3) mechanistic research design, and (4) qualitative and mixed methods approaches. The research and training opportunities offered by this fellowship will be supported by the thriving research environment of University of California, Berkeley and mentorship from the applicant’s Sponsor (Dr. Allison Harvey) and expert Consultants (Drs. Shannon Wiltsey Stirman, Cara Lewis, and Sophia Rabe-Hesketh). Collectively, this F32 fellowship will support the applicant’s career goals of becoming an independent investigator in implementation science with a program of research that evaluates the predictors, mechanisms, and outcomes of implementation and sustainability of EBTs in community settings.