PROJECT SUMMARY Substance use and associated HIV, hepatitis C (HCV), and mental health comorbidities continue to drive morbidity and mortality. Interdisciplinary, interinstitutional collaborations can challenge paradigms to achieve advances in substance use treatment that limit the spread of HIV/HCV and decrease morbidity and death. Vanderbilt University Medical Center (VUMC) and Oregon Health and Science University (OHSU) are national leaders in substance use research and are located in states with high rates of substance use and new HIV infections. For these reasons, this application seeks to establish the Vanderbilt Oregon COllaborative Scholar Training in Addiction Research (COSTAR) K12 program to train and mentor the next generation of substance use researchers. We propose to support a minimum of three faculty Scholars who have completed an MD or PhD in the health sciences at a level of 75% effort for up to five years. VUMC and OHSU have a rich research environment and highly successful history of developing the careers of research scientists . Additional strengths of VUMC/OHSU include four addiction fellowship programs, the Tennessee Center for AIDS Research, the Vanderbilt Center for Tobacco Addiction and Lifestyle at VUMC and the Western States Node of the National Drug Abuse Treatment Clinical Trials Network, the Portland Alcohol Research Center, and the Rural Opioids Initiative at OHSU. In this application, Drs. Tindle (nicotine dependence), Freiberg (unhealthy alcohol use), and Korthuis (drug use) will partner with interdisciplinary faculty mentors from both VUMC and OHSU to develop and implement COSTAR. The COSTAR training curriculum includes (1) mentored research projects, (2) didactic education, (3) completion of a structured institutional career development program, and (4) optional multisite research training. COSTAR objectives and Specific Aims: 1. To create a sustainable K12 program that fosters interdisciplinary, intensive mentored research training and career development for early career MD, PhD, MD/PhD investigators that focuses on substance use/disorders with an emphasis on vulnerable populations (e.g., people with HIV); 2. To produce a diverse group of well-trained Scholars with the expertise to study: the risk factors for, and mechanisms underlying, substance use/disorders, and the behavioral and health disparity aspects of substance use/disorders and its associated morbidity; 3. To provide Scholars with a research environment that offers mentors and topic experts with expertise in key research domains and protected time to innovate and build an individualized research program; 4. To leverage VUMC and OHSU existing infrastructure and location to provide Scholars with hands-on instruction in a mentor’s laboratory, didactic education, access to existing cohort/trial data and statistical support and facilitate participation in a mentored research project that leads to an R01 or external career development award submission; an...