Hospital-Based Psychosocial Case Management and Suicide Prevention in South Korea: A Randomized Clinical Trial

South Korea maintains the highest suicide rate in the Organization for Economic Cooperation and Development, with major depressive disorder (MDD) being the leading diagnosis among suicide deaths. Evidence from large-scale randomized clinical trials (RCTs) is limited, particularly for diagnosis-specific, long-term programs in outpatient settings.

To evaluate the effectiveness of a structured, hospital-based case management program in reducing suicidal ideation and associated clinical outcomes among patients with MDD.

This RCT was conducted at 6 general hospitals in South Korea from January 18, 2021, to July 31, 2024. Participants included outpatients 18 years or older with MDD who had current suicidal ideation or a suicide attempt within the past 2 months. All efficacy analyses were performed according to the intention-to-treat principle.

Participants were randomized 1:1 to receive either 6 months of structured assertive case management (ACM) as an adjunct to standard treatment (n = 158) or usual psychiatric care alone (control [n = 156]).

The primary outcome was the change from baseline to 6 months in the overall severity of suicidal thoughts and behaviors (STBs), as assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS). Secondary outcomes included changes in depression, suicidal intent and ideation, anxiety, loneliness, impulsivity, quality of life, and service utilization.

Of 314 participants enrolled (mean [SD] age, 32.3 [13.1] years; 207 [65.9%] female), 158 were randomized to the ACM group and 156 to the control group; 245 (132 in the ACM and 113 in the control groups) completed the 6-month follow-up. The ACM group showed a significantly greater mean (SD) reduction in C-SSRS total score than the control group (-9.22 [0.49] vs -7.23 [0.50]; adjusted mean difference, -1.99 [95% CI, -3.37 to -0.61]; P = .005). Greater mean improvements were also observed in the ACM group for depressive symptoms (Hamilton Depression Rating Scale mean [SD] change, -9.19 [0.70] vs -6.23 [0.69]; P = .003), suicidal ideation (Beck Scale for Suicidal Ideation mean [SD] change, -7.96 [0.62] vs -5.58 [0.75]; P = .01), and anxiety (Generalized Anxiety Disorder-7 mean [SD] change, -3.90 [0.44] vs -1.85 [0.48]; P = .002). No significant between-group differences were observed in suicide attempts, and 1 suicide death occurred in the control group.

In this RCT of outpatients with MDD and high suicide risk, ACM significantly reduced C-SSRS total scores and psychological distress compared with usual care. These findings provide a critical, high-level evidence base for the national implementation of standardized, hospital-centered psychosocial interventions as a scalable public health strategy for suicide prevention.

Clinical Research Information Service Identifier: KCT0008123.