of Diversity Supplement Recent efforts have successfully trained providers to deliver evidence-based treatments (EBTs) in community mental health centers (CMHCs); however, many CMHCs have not sustained these initiatives. The proposed research is responding to the urgent calls for empirical investigation on key mechanisms of sustainment in this context. The Parent R01 seeks to examine if TranS-C, an EBT targeting sleep and circadian dysfunction in SMI, can be effectively delivered and sustained by community providers within CMHCs. Providers will be trained using a promising, yet understudied, mechanism of sustainment: train-the-trainer. Two generations of training will be utilized: Generation 1, in which UC Berkeley expert trainers train community providers to deliver TranS-C; and Generation 2, in which a select group of community providers are trained to train others within their community site. The proposed research supplement will extend the Parent R01 by empirically evaluating differences between Generation 1 and Generation 2. We will study a sample of at least 128 providers in Alameda County CMHCs over the 2-year Implementation period. Considering both the transfer of learning and social identity theories, we will evaluate differences between Generation 1 and Generation 2 in provider acceptability, appropriateness and feasibility ratings of TranS-C and provider knowledge using provider post-training evaluations. Additionally, we will develop a Gold Standard Training Checklist and conduct exploratory analyses to compare Generation 1 and Generation 2 trainings in the use of gold standard training elements. This supplement will contribute to the science of sustainment by providing a deeper understanding of how we can effectively train community providers in an EBT and sustain its delivery to reach the most underserved members of our communities.