PROJECT SUMMARY/ABSTRACT Traumatic brain injury (TBI) is a major public health crisis for adults in the U.S. and globally. TBI can lead to new or worsened substance use disorders (SUDs) and mental health comorbidities. Strikingly, TBI can contribute to a 10-fold increase in the likelihood of unintentional overdose. TBIs are especially common among adults who seek treatment for SUDs and other mental health comorbidities in behavioral health treatment organizations. Effective and evidenced-based TBI screening methods exist (e.g., the Ohio State University TBI Identification Method) that can be used by behavioral health providers to identify lifetime history of TBI among clients; yet, providers have failed to adopt TBI screening into routine behavioral healthcare. Lack of TBI identification could affect clinical care decisions and client outcomes. However, studies have yet to investigate the determinants influencing TBI screening adoption among behavioral health providers in behavioral health treatment organizations. The primary aims of this proposal are guided by the Theory of Planned Behavior (TBP) and Roger’s Diffusions of Innovations Theory (DOI). I propose to conduct a prospective cohort study to investigate whether provider-level characteristics from the TBP (attitudes, subjective norms, perceived behavioral control, intentions), and innovation-level factors from the DOI (acceptability, feasibility, and appropriateness of TBI screening) affect the adoption of TBI screening in behavioral health treatment contexts. Using mixed methods, I propose three specific aims: (1) Examine the relationships between behavioral health providers’ attitudes, perceived behavioral control, and subjective norms as predictors to TBI screening intentions and examine whether intentions to adopt TBI screening predicts actual TBI screening behaviors at a one month follow-up; (2) Investigate whether the acceptability, feasibility, and appropriateness of TBI screening moderates the relationship between TBI screening intentions and actual screening behaviors; and (3) Qualitatively assess the contextual determinants to TBI screening adoption through semi-structured interviews. This proposed study is a necessary advancement toward the translation and implementation of existing and effective innovations developed for adults with TBI within behavioral healthcare contexts. A training plan consisting of individualized mentorship, formal coursework in advanced statistical techniques, and experiential learning has been designed to ensure the proposed study is conducted rigorously and to develop my skills in leading cutting-edge research as an independent investigator in the dissemination and implementation of effective innovations for TBI.