Transcranial random noise stimulation for the acute treatment of depression: a randomized controlled trial

Abstract

Background Transcranial electrical stimulation has broad potential as a treatment for depression. Transcranial random noise stimulation (tRNS), which delivers randomly fluctuating current intensities, may have greater cortical excitatory effects compared to other forms of transcranial electrical stimulation. We therefore aimed to investigate the antidepressant efficacy of tRNS. Methods Depressed participants were randomly assigned by computer number generator to receive 20 sessions of either active or sham tRNS over four weeks in a double-blinded, parallel group randomized-controlled trial. tRNS was delivered for 30mins with a direct current offset of 2mA and a random noise range of 2mA. Primary analyses assessed changes in depression severity using the Montgomery-Asperg Depression Rating Scale (MADRS). Neuroplasticity, neuropsychological, and safety outcomes were analysed as secondary measures. Results 69 participants were randomised, of which three discontinued treatment early leaving 66 (sham n = 34, active n = 32) for per-protocol analysis. Depression severity scores reduced in both groups (MADRS reduction in sham = 7.0 [95%CI 5.0-8.9]; and active = 5.2 [95%CI 3.2-7.3]). However, there were no differences between active and sham groups in the reduction of depressive symptoms, or the number of participants meeting response (sham = 14.7%; active = 3.1%) and remission criteria (sham = 5.9%; active = 0%). Erythema, paraesthesia, fatigue, and dizziness/light-headedness occurred more frequently in the active tRNS group. Neuroplasticity, neuropsychological and acute cognitive effects were comparable between groups. Conclusion Our results do not support the use of tRNS with the current stimulation parameters as a therapeutic intervention for the treatment of depression. Clinical trial registration at clinicaltrials.gov/NCT01792414.