PROJECT ABSTRACT Suicide is a leading cause of death, and the approximately 1 million suicide attempts that occur in the US each year represent a major societal and public health burden. Individuals identified as high risk for suicide are often admitted for inpatient mental health treatment; however, there are few interventions known to reduce suicides or suicide attempts during the high-risk period after hospital discharge. Peer support is a novel intervention approach to address two empirically supported risk factors for suicide, thwarted belongingness and hopelessness, during high-risk periods. PREVAIL is a suicide prevention intervention developed in a prior study to be delivered by peer support specialists, individuals with a lived experience of mental health challenges who have achieved stable recovery and are trained to support others at risk. PREVAIL consists of 3 months of one-to-one sessions in which peer support specialists share their experiences related to suicide and engage in semi-structured discussions to improve hope and belongingness among recipients. The PREVAIL R01 effectiveness-implementation trial was funded to determine whether PREVAIL is effective at reducing suicide attempts and suicidal ideation, whether improvement in hopelessness and belongingness explain improvements in suicide-related outcomes, and to identify barriers and facilitators to implementation of PREVAIL by health systems. The trial had been successfully meeting its recruitment milestones until March 2020 when in-person recruitment at both participating inpatient units was stopped due to the COVID-19 pandemic. Over the course of the subsequent year new protocols were put into place to recruit patients remotely and eventually return to in-person recruitment; however, the number of admissions at each site and the rate of recruitment continues to be lower than prior to the pandemic. Due to the impact of COVID-19, the study will not be able to reach its original recruitment goal of 490 enrolled participants under the remaining budget and timeline. The recruitment shortfall, if not addressed, will adversely limit the power of the study to detect a difference with respect to the primary outcome of suicide attempts. To address the impact of COVID-19, we propose to add an additional recruitment site to achieve the original target enrollment of the PREVAIL trial and achieve adequate power to determine the effectiveness the peer specialist intervention for reducing suicide attempts. The additional site will be a 48-bed inpatient unit within the Henry Ford healthcare system, which was chosen in part because the study has already received institutional review board approval for the current Henry Ford recruitment site. By achieving our full study sample, we also propose to compare remote vs. in-person implementation of the intervention on measures of acceptability and suicidal ideation. Due to the COVID-19 pandemic, the PREVAIL intervention shifted from primarily in-...