High-Definition Transcranial Direct Current Stimulation–Primed Intermittent Theta Burst Stimulation in Treatment-Resistant Depression

Treatment-resistant depression (TRD) is a common problem faced by clinicians worldwide with no agreed upon treatment protocol. Priming is a technique that can enhance the sensitivity of the brain to therapy using techniques that increase or decrease the excitability of the cortex. Studies on cross-modality priming remain sparse. Objectives The aim of this study was to evaluate whether high-definition transcranial direct current stimulation (HDtDCS) priming improves the efficacy of intermittent theta burst stimulation (iTBS) in improving TRD. Methodology A prospective hospital-based, randomized control study where the participants were divided into active or sham HDtDCS-primed iTBS stimulation groups for a total of 10 sessions and were assessed on clinical parameters at baseline, end of week 1, and end of week 2 was done. Primary outcome of the study was the difference in Hamilton Depression Rating Scale (HDRS) scores over 2 weeks of HDtDCS-primed iTBS. Result A significant effect of time was seen over HDRS scores in both active and sham groups with a large effect size. Significant effect of time was also found over the Clinical Global Impressions-Severity Scale scores of patients with a large effect size. The difference in the improvement in depressive severity as measured using HDRS and Clinical Global Impressions-Severity Scale scores between active and sham groups was also found to be significant with large effect sizes. Conclusion High-definition tDCS–primed iTBS is superior to normal iTBS in patients with depression who have failed a trial of 2 antidepressants, whereas both mechanisms are of benefit to the patients.