PROJECT SUMMARY The opioid epidemic is inextricably intertwined with our nation's criminal justice system. At least 20% of people with opioid use disorder (OUD) were involved in the criminal justice system, and individuals just released from jail have an eight times higher risk of drug overdose compared with the general population. Given this risk, several jails now treat OUD with medications, but these efforts will be ineffective if they fail to connect people with OUD to care upon release. Housing instability, food insecurity, lack of social support, mistrust in the health system, and co-morbid physical and mental health conditions threaten a person's ability to engage and remain in community OUD treatment. Prior work has not identified effective strategies to engage justice-involved individuals in OUD care that are feasible and honor patients' values, preferences, and needs. Until this knowledge gap addressed, it will be difficult to reduce opioid-related morbidity and mortality in the United States. The overall objective of this study is to assess whether the Transitions Clinic Network (TCN) program, which provides enhanced primary care and OUD treatment for people recently released from incarceration, improves measures in the opioid treatment cascade. In TCN, formerly incarcerated community health workers are embedded within primary care teams and address social determinants of OUD, provide social support, help patients build trust in the health system and advocate in interactions with the criminal justice system. The central hypothesis of Transitions Clinic Network: Post Incarceration Addiction Treatment, Healthcare, and Social Support (TCN PATHS) study is that TCN program participation improves opioid treatment cascade measures among those with OUD just released from jails. TCN PATHS (1UG1DA050072-05) is a hybrid type I effectiveness-implementation trial, the goal of which is to randomize 400 people with OUD just released from 5 local jails (Minneapolis, MN, Bridgeport, CT, Durham, NC, Caguas, PR, and Bronx, NY) to compare the effectiveness of the TCN intervention versus referral to standard primary care on opioid treatment cascade outcomes and whether housing, food access, criminal justice contact, and social support mediate this association. To date, we have recruited 238 participants and are seeking additional funding to finish the study and evaluate 6-month outcomes on OUD treatment cascade. The administrative supplement will thus preserve the likelihood for the project to answer TCN PATHS's primary study question, and we will focus recruitment and retention in only three of the sites but complete participant follow-up in two others. Furthermore, the supplement will increase the likelihood of supporting independent scientific research careers for two junior faculty who have received NIH supplements to study how novel factors, including sleep and self-stigma, affect OUD treatment outcomes.