Suicide is the second leading cause of death for US adolescents. Youth at highest risk of suicide are often ad- mitted to inpatient psychiatric units when safety in the community is unable to be maintained. However, access to these services has decreased over the last several decades as availability of adolescent inpatient psychiat- ric beds has steadily declined. Against this backdrop, inpatient admissions for suicidal behavior and intentional self-injury among youth have more than doubled from 2006 to 2015. Limited access to, and demand for these services has created the need for additional options to provide short-term crisis intervention and stabilization services in a secure setting. In direct response to PAR-20-286, this proposal examines high-impact practice- based research with near-term potential to address NIMH suicide prevention priorities. We previously devel- oped Intensive Crisis Intervention (ICI), a brief, evidence-based treatment that incorporates Family Therapy/ Parent Training, Cognitive Behavioral Therapy and Motivational Interviewing to target family functioning in re- ducing adolescent suicidal behavior. An open pilot trial on our Youth Crisis Stabilization Unit (YCSU) demon- strated that ICI is feasible, acceptable, and associated with improved clinical outcomes over a 3-month follow- up period. In addition, average length of stay for adolescents receiving ICI was 5.8 days briefer than those re- ceiving traditional psychiatric inpatient care. There were no significant differences in readmission rates or time to readmission across the two settings. We now propose to further develop and test ICI. We will recruit 80 ado- lescents presenting to Nationwide Children’s Hospital (NCH) Psychiatric Crisis Department with suicidal idea- tion and behavior that are eligible for admission to both the NCH YCSU and Adolescent Psychiatric Inpatient Unit. During Year 1, 20 adolescents and one of their parents/guardians will be enrolled in a nonrandomized case series. In-depth qualitative interviews with patients, parents, and providers will be used to further refine the ICI manual, training and supervision protocols, and fidelity/adherence measures, and identify barriers to, and facilitators of implementation and sustainability. In Years 2 and 3, 60 adolescents will be enrolled in a ran- domized controlled trial (RCT) comparing ICI with traditional inpatient psychiatric treatment. The project’s main goal is to examine feasibility, acceptability, research implementation procedures, and preliminary effectiveness of ICI using a mixed-methods approach. We hypothesize that ICI will be acceptable to families and show greater improvements in our proposed mechanism of change, family functioning, compared with traditional in- patient treatment at discharge, 30 days, and 3-month follow-up. Secondary aims will assess preliminary treat- ment effects of ICI on suicidal ideation, attempts, ED/hospital admission, hopelessness and therapeutic alli- ance. Th...