Adjunctive duration-doubled tDCS for the treatment of depressive patients with suicidal ideation: study protocol for a double-blind, randomized, sham-controlled trial

Abstract Backgroud: The problem of suicide has become increasingly common in individuals with major depressive disorder (MDD). Transcranial direct current stimulation (tDCS) is an effective treatment for MDD with2 milliamperes (mA) for at least thirty minutes per day for two weeks. This study aims to investigate the efficacy of daily duration-doubled tDCS as an adjunctive intervention for rapidly reducing suicidal ideation and improving depression in MDD patients. Methods and design: In this double-blind, randomized, sham-controlled study, 76 MDD patients with suicidal ideation are randomly assigned to either active (n=38) or sham (n=38) tDCS group. The anode and cathode are placed over the scalp areas corresponding to left and right dorsolateral prefrontal cortex (DLPFC), respectively, and each stimulation lasts for 60 minutes. The primary outcome is defined as change of Beck Scale for Suicide Ideation (BSI) after 10 sessions. The 17-item Hamilton Depression Rating Scale (HAMD-17), Wisconsin Card Sorting Test (WCST) and Stroop Color-Word Test (SCWT) are utilized to assess depressive symptoms, executive function. Blood biomarkers related to suicidal ideation are collected at baseline and after 10 sessions. Discussion: This study suggest the adjunctive duration-doubled tDCS might be a novel method to rapidly reduce suicidal ideation and improve depressive symptom. The variation of biomarkers could be potential predictive models of suicide risk. Trial registration: The trial protocol is registered with ClinicalTrials.gov under protocol registration number NCT05555927. Registered on September 25, 2022.