Follow-up effects of transcranial direct current stimulation (tDCS) for the major depressive episode: A systematic review and meta-analysis

• Published in: Psychiatry research 2021-08, Vol.302, p.114024-114024, Article 114024
• Main Authors: Razza, Laís B., De Smet, Stefanie, Moffa, Adriano, Sudbrack-Oliveira, Pedro, Vanderhasselt, Marie-Anne, Brunoni, André R.
• Format: Article
• Language: English
• Subjects: Depression; Follow-up; Long-term effects; Meta-analysis; Transcranial direct current stimulation
• ISSN: 0165-1781; 1872-7123
• DOI: 10.1016/j.psychres.2021.114024

•We investigated the follow-up effects of tDCS for depression.•We searched for studies with a follow-up period after tDCS treatment for an acute major depressive episodes.•A moderate-to-large improvement of the antidepressant tDCS effects in the follow-up phase was found.•Primary outcome may be driven by the effect size of the interventional studies (with active tDCS).•No predictor of response was significantly associated with the outcome. Transcranial Direct Current Stimulation (tDCS) is an effective treatment during the acute phase of a major depressive episode (MDE), although the evidence for its follow-up efficacy is mixed. A systematic review and meta-analysis were performed. MEDLINE/PubMed, Scopus (EMBASE), Web of Science, Cochrane Library and additional sources were searched from inception to April 29, 2021. Studies that followed up adults treated with tDCS during an MDE - using (interventional) and/or not using (observational) tDCS in the follow-up period were included. The primary outcome was the Hedges' g for the follow-up depression scores. Small study effects and sources of heterogeneity were explored. 427 studies were retrieved and 11 trials (13 datasets, n = 311) were included, most presenting moderate bias. Results showed a follow-up depression improvement (k = 13, g = -0.81, 95% confidence interval [CI]: -1.28; -0.34, I² = 84.0%), which was probably driven by the interventional studies (k = 7, g= -1.12, 95% CI: -1.84; -0.40, I² = 87.1%). No predictor of response was associated with the outcome. No risk of publication bias was found. Significant between-study heterogeneity may have influenced the overall results. Our findings suggest that tDCS produces effects beyond the intervention period during MDEs. Maintenance sessions are advised in future research.