RANDOMIZED CONTROLLED TRIAL OF A SINGLE-SESSION MECHANISM-FOCUSED INTERVENTION FOR SUICIDAL THOUGHTS AND BEHAVIORS

Suicide remains a critical public health concern, with increasing rates and millions experiencing suicidal ideation annually. Although evidence-based treatments exist, many are time-intensive, underutilized, and often inaccessible to high-risk individuals, especially those recently discharged from inpatient psychiatric care. Brief, scalable interventions targeting core psychological mechanisms implicated in suicidal thoughts and behaviors (STBs) are needed. This study evaluated a novel Single Session Mechanism-Focused Intervention (SSMFI) designed to reduce hopelessness and negative perceptions of social relatedness among adults hospitalized for STBs. In a randomized controlled trial (N = 38) conducted on two inpatient psychiatric units, participants were assigned to either the SSMFI or an active control condition focused on distress tolerance skills. Assessments occurred pre-intervention, post-intervention, and at one-week and one-month follow-ups, measuring STBs, mechanisms (hopelessness, thwarted belongingness, perceived burdensomeness), and feasibility/acceptability. Results indicated high feasibility and acceptability. While the SSMFI did not produce significantly greater immediate changes in targeted mechanisms compared to the control, participants in the active control condition showed significantly greater improvements in hopelessness and perceptions of social relatedness at one-week follow-up, though these effects were not sustained at one month. No significant differences emerged in suicidal ideation or behavior, or outpatient appointment attendance. Findings suggest that while the SSMFI is feasible and well-received in acute settings, single-session mechanism-focused approaches may require refinement and additional support to achieve lasting clinical impact. Integrating brief, theoretically driven interventions in inpatient care may offer a promising avenue to improve suicide prevention during critical care transitions.