Peer PLUS: A Client-Centered Digital Intervention for Addressing the Needs of Individuals with Substance Use Disorder - PROJECT SUMMARY/ABSTRACT Over the past three decades, substance use disorder (SUD) has emerged as a major public health crisis. More than 70% of overdose deaths in the U.S. involve a synthetic opioid, which makes successful treatment critical to those with SUD. However, the relapse rate is estimated at 40-60%, and those with SUD are also at risk for long-term medical issues. Thus, SUDs are often chronic conditions that require early and consistent engagement in treatment to achieve long-term recovery. One effective method of engagement that health care systems have implemented is matching recoverees with peer recovery coaches (PRCs) to help navigate them through treatment. These at-elbow support coaches provide consistent, non-judgmental communication and referral to various treatment and wraparound services, including medication assisted therapy (MAT), which is considered the most effective treatment for opioid use disorder. In this project, we propose a randomized controlled trial to evaluate a novel technology tool: Peer PLUS (People Leveraging Urgent Support). Peer PLUS is a standalone, HIPAA-compliant mobile app that facilitates and tracks secure communication between PRCs and their clients, referrals to community resources, and other recovery activities. The companion website allows a team of PRCs to collectively manage a pool of clients, offering more comprehensive coverage. We expect this point-of-care app to enhance communication between recoverees and their PRCs and improve self-reported recovery outcomes. Additionally, Peer PLUS will provide a source of data to help capture the care coordination efforts associated with peer coaching. Through our strategic clinical trial and dissemination plan, we anticipate this intervention to be scaled for support of recovery across different types of community partners with eventual extension to PRCs supporting other types of mental health crises (e.g., post-suicide attempt). Implementation science constructs infused with user-centered design strategies will be used to scaffold our Peer PLUS evaluation and implementation toolkit development in the first phase of this project (R21), which will provide a critical foundation for the randomized controlled trial and second site pilot proposed in the second phase (R33). Because both the app and companion website are not tied to any specific organization and the modular software is adaptable, this will be a low-cost, easily- implementable option for any group that offers peer recovery support services.