BackgroundJuvenile justice (JJ) youth are at high risk of opioid and other substance use (SU), dysfunctional family/social relationships, and complex trauma. The purpose of the Leveraging Safe Adults (LeSA) Project is to examine the effectiveness of Trust-Based Relational Intervention® (TBRI®; leveraging family systems by providing emotional and instrumental guidance, support, and role modeling) in preventing opioid and other SU among youth after release from secure residential facilities.MethodsAn effectiveness-implementation Hybrid Type 1 design is used to test the effectiveness of TBRI for preventing non-medical use of opioids among JJ-youth (delayed-start at the site level; a randomized controlled trial at participant level) and to gain insight into facility-level barriers to TBRI implementation as part of JJ re-entry protocols. Recruitment includes two samples (effectiveness: 360 youth/caregiver dyads; implementation: 203 JJ staff) from nine sites in two states over 3 years. Participant eligibility includes 15 to 18-year-olds disposed to community supervision and receiving care in a secure JJ facility, without active suicide risk, and with one caregiver willing to participate. Effectiveness data come from (1) youth and caregiver self-report on background, SU, psychosocial functioning, and youth-caregiver relationships (Months 0, 3, 6, 12, and 18), youth monthly post-release check-ins, and caregiver report on youth psychological/behavioral symptoms, and (2) JJ facility records (e.g., recidivism, treatment utilization). Fidelity assessment includes post-session checklists and measures of TBRI strategy use. Collected four times over four years, implementation data include (1) JJ staff self-report on facility and staff characteristics, use of trauma-informed care and TBRI strategies, and (2) focus groups (line staff, leadership separately) on use of trauma-informed strategies, uptake of new interventions, and penetration, sustainment, and expansion of TBRI practices.DiscussionThe LeSA study is testing TBRI as a means to empower caregivers to help prevent opioid use and other SU among JJ-youth. TBRI’s multiple components offer an opportunity for caregivers to supplement and extend gains during residential care. If effective and implemented successfully, the LeSA protocol will help expand the application of TBRI with a wider audience and provide guidance for implementing multi-component interventions in complex systems spanning multiple contexts.Trial registrationClinicalTrials.govNCT04678960; registered November 11, 2020; https://clinicaltrials.gov/ct2/show/NCT04678960.