Transcranial direct current stimulation for major depressive disorder: systematic review and meta-analysis

Abstract

Major Depressive Disorder (MDD) is a severe mental disorder characterized by depressed mood and a decrease in pleasure or interest in all or almost all activities. About 30% of patients do not respond to a conventional drug treatment. Non-invasive brain stimulation techniques, such as Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Continuous Stimulation (tDCS), have been used in MDDs treatment. Furthermore, several clinical trials and meta-analysis have been done using tDCS as a treatment for patients with MDD. The objective of this proposal is to carry out a systematic review of the literature and meta-analysis to verify the evidence of the efficacy of tDCS in the treatment of depressive syndrome. This study is important because three large-sample clinical trials have recently been published that have not yet been incorporated into meta-analyses. The study will be performed according to Cochrane recommendations and guidelines of the PRISMA group; and the protocol of the study will be registered in the platform PROSPERO. First, the systematic review will be done by searching for clinical trials for the treatment of the disease with the use of tDCS in the PubMed/Medline database, and complemented using the databases of WebofScience and SCOPUS, the clinicaltrials.gov platform and with the contact of experts in the area. We will include randomized clinical trials evaluating the efficacy of tDCS in depression. We will assess the quality of the studies using the Cochrane bias risk tool. Quantitative outcomes will be response, remission and dropout rates, as well as clinical improvement on the depression scale. Risks of biases will also be evaluated using meta-regression techniques, funnel graphs and sensitivity analyses.