Effectiveness of a Suicide Prevention Module for Adults in Substance Use Disorder Treatment: A Stepped-Wedge Cluster-Randomized Clinical Trial

IMPORTANCE: Individuals with substance use disorders (SUDs) are at high risk for suicide. The Preventing Addiction Related Suicide (PARS) module is the first suicide prevention module developed in and for community substance use intensive outpatient programs (IOPs). OBJECTIVE: To evaluate the effectiveness of PARS on suicide-related outcomes (ie, knowledge, attitudes, and help-seeking behavior) compared with usual care. DESIGN, SETTING, AND PARTICIPANTS: This stepped-wedge cluster-randomized clinical trial was conducted from 2017 to 2020, with follow-up assessments conducted after treatment and at 1, 3, and 6 months. Participants included adult outpatients in SUD treatment at community IOPs across western Washington state. Data were analyzed from July 1, 2020, to January 20, 2022. INTERVENTIONS: The intervention, PARS, was a 1-session secondary prevention module administered by trained SUD counselors consisting of didactic presentations and group discussions about suicide risk factors, warning signs, and actions to take if suicide risk is observed in self or others. The control group received usual care. MAIN OUTCOMES AND MEASURES: Primary outcomes were suicide knowledge, attitudes about suicide, and help-seeking behavior among patients enrolled in an IOP. RESULTS: A total of 906 participants (mean [SD] age, 37.5 [12.0] years; 540 [59.6%] men) were included, with 478 participants receiving usual care and 428 participants receiving PARS. In intent-to-treat analysis from baseline to after treatment, there was a greater improvement in suicide knowledge (d = 0.15; 95% CI, 0.08 to 0.23; P < .001) and a greater reduction in maladaptive attitudes (d = 0.18; 95% CI, 0.14 to 0.25; P < .001) for PARS participants compared with those receiving usual care. Improvements were maintained at follow-up for suicide knowledge (1 month: d = 0.16; 95% CI, 0.07 to 0.22; P < .001; 3 months: d = 0.12; 95% CI, 0.05 to 0.19; P = .001; 6 months: d = 0.13; 95% CI, 0.06 to 0.20; P < .001) and reductions in maladaptive attitudes (1 month: d = 0.20; 95% CI, 0.12 to 0.23; P < .001; 3 months: d = 0.10; 95% CI, 0.05 to 0.16; P < .001; 6 months: d = 0.14; 95% CI, 0.09 to 0.19; P < .001), with 788 participants (87.0%) of the sample responding across time points. From baseline to 6 months, there was a greater improvement in help-seeking in the PARS group vs usual care (d = 0.16; 95% CI, 0.01 to 0.32; P = .04). CONCLUSIONS AND RELEVANCE: This stepped-wedge cluster-randomized clinical trial found that PARS was superior to usual care in improving suicide knowledge, maladaptive attitudes, and help-seeking in adults undergoing community addiction treatment. As a 1-session IOP module developed in partnership with community addiction agencies, PARS has the potential for wide impact in the national suicide prevention strategy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03166709