Depression is a general term that describes different depressive disorders which are highly prevalent and disabling, characterized by decreases in quality of life. Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain modulation technique used, among other purposes, for the treatment of chronic pain and headache. In order to clarify the effect of this stimulation on depressive disorders, the objective of this review was to evaluate efficacy and safety of treatment with tDCS for depressive disorders.

A systematic research study was carried out on 30 June 2022 in MEDLINE (by Pubmed), Embase, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), PsycInfo e Global Mental Health databases. Were included systematic reviews (SR) with meta-analysis that selected patients with depression, in use of tDCS, using as comparator sham stimulation (placebo) or any other treatment (pharmacologic or no) or any comparison between pre-and post-intervention.

Eight SR with meta-analysis of randomized clinical trials (RCTs) on the efficacy and safety of tDCS in the treatment of depressive disorders were retrieved. Subjects were assessed for clinical response, remission, change in scores on depression scales, occurrence of procedure-related adverse events, and treatment dropout. Three systematic reviews showed results that point to the effectiveness of tDCS for the clinical response outcome and one considering the remission outcome. As for the outcome measured by the change in depression scale scores, all included reviews showed favorable results for tDCS. It is noteworthy that the studies included in the reviews have methodological limitations. With regard to safety, an increased risk treatment-emergent mania or hypomania (TEM) has been observed.

The tDCS association with antidepressants showed favorable results to this technology in a sample with depression and varied clinical characteristics. Regarding safety of this technology, tDCS did not show adverse effects of greater severity, but was verified to have an increased risk of TEM.