Advancing Suicide Intervention Strategies for Teens (ASSIST): study protocol for a multisite randomised controlled trial.

INTRODUCTION: Brief interventions that reduce suicide risk following youth's experience with acute care due to suicidality are needed. METHODS AND ANALYSIS: The study will use a three-arm randomised controlled trial designed to test the effectiveness of the Safety Planning Intervention with structured follow-up (SPI+) and the Collaborative Assessment and Management of Suicidality (CAMS) compared with enhanced usual care. The primary outcomes measure will be suicidal events, defined as death by suicide, attempted suicide, preparatory acts toward imminent suicidal behaviour or suicidal ideation resulting in a change in emergency evaluation or inpatient admission. Secondary measures will be the number of suicide attempts and severity of suicidal ideation. The experimental interventions, SPI+ and CAMS, consist of up to eight sessions over approximately 8 weeks that are designed to manage (SPI+) or treat (CAMS) patient-identified 'drivers' of suicidal thoughts and behaviours. Mechanisms and moderators of change will be evaluated to understand treatment impacts. ETHICS AND DISSEMINATION: This study has been approved by the Seattle Children's Institutional Review Board and is monitored by external agencies including the University of Washington Institute for Translational Health Sciences, and a National Institute of Mental Health (NIMH)-appointed Data Safety and Monitoring Board. Trial results will help establish evidence towards safe and effective treatment strategies for youth transitioning from acute to outpatient care due to a suicidal crisis. The data will be shared with the NIMH Data Archives and disseminated through publications and conferences. TRIAL REGISTRATION NUMBER: NCT05078970.