Reducing Intrusive Suicidal Mental Images in Patients With Depressive Symptoms Through a Dual-Task Add-on Module: Results of a Multicenter Randomized Clinical Trial

Objective: To examine the safety and efficacy of a brief cognitive dual-task (using eye movements) add-on module to treatment as usual (TAU) in reducing the severity and frequency of intrusive suicidal mental images and suicidal ideation. Method: We conducted a single-blind, parallel multicenter randomized trial (No. NTR7563) among adult psychiatric outpatients (N = 91; M_age = 34.4, SD = 13.54; 68% female) with elevated depressive symptoms and experiencing distressing suicidal intrusions in the Netherlands. Primary outcome was the severity (Suicidal Intrusions Attributes Scale) and frequency (Clinical Interview for Suicidal Intrusions) of suicidal mental imagery intrusions at 1-week posttreatment and 3-month follow-up. Primary analysis was intention-to-treat. Results:Between November 27, 2018 and September 13, 2021, 91 patients were included and randomly assigned to intervention group (Cognitive Dual Task Add-on+TAU) (n=46) or TAU-only (n=45). Cognitive Dual Task Add-on+TAU had greater reductions in severity (mean difference,−15.50, 95% CI [23.81,−7.19]; p<.001, d= 0.60), and frequency (geometric mean difference, 0.47, 95% CI [0.29, 0.79]; p =.004) of suicidal intrusions over time than TAU-alone. Cognitive Dual Task Add-on + TAU patients also showed lower suicidal ideation over time (p=.008, d =0.42). There were no significant group differences in reductions in depressive symptoms, rumination, or hopelessness. Four serious adverse events occurred (three Cognitive Dual Task Add-on + TAU; one TAU-only); all unlikely attributable to intervention/trial. Conclusions: Findings provide support for the effectiveness of adding a cognitive dual-task module to the treatment of psychiatric outpatients with elevated depressive symptoms in reducing suicidal intrusions and ideation and can be executed safely.