Noninvasive brain stimulation in psychiatric disorders: a primer

Objective: Noninvasive brain stimulation (NIBS) techniques, such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), are increasingly being used to treat mental disorders, particularly major depression. The aim of this comprehensive review is to summarize the main advances, limitations, and perspectives of the field. Methods: We searched PubMed and other databases from inception to July 2017 for articles, particularly systematic reviews and meta-analyses, evaluating the use of NIBS in psychiatric disorders. Results: We reviewed the mechanisms of action, safety, tolerability, efficacy, and relevant clinical parameters of NIBS. Repetitive TMS is already an established technique for the treatment of depression, and there is theoretically room for further methodological development towards a high-end therapeutic intervention. In contrast, tDCS is a technically easier method and therefore potentially suitable for wider clinical use. However the evidence of its antidepressant efficacy is less sound, and a recent study found tDCS to be inferior to antidepressant pharmacotherapy. Clinical trials using rTMS for other mental disorders produced mixed findings, whereas tDCS use has not been sufficiently appraised. Conclusion: The most promising results of NIBS have been obtained for depression. These techniques excel in safety and tolerability, although their efficacy still warrants improvement.

Novel neurotherapeutics in psychiatry: use and rationale of transcranial direct current stimulation in major depressive disorder / Novas neuroterapêuticas em psiquiatria: racional e uso da estimulação transcraniana por corrente contínua no transtorno depressivo maior

Background: Transcranial direct current stimulation (tDCS) is a novel non-pharmacological intervention being investigated for the treatment of major depressive disorder (MDD). Objective: To perform an updated review of tDCS for MDD. Method: Systematic review in Medline/PubMed and other databases of all clinical studies evaluating the clinical efficacy of tDCS in MDD, from the first date available to December/2013. Results: Out of 55 articles, 24 were included, being 6 open-label studies; 8 randomized, double-blind, sham-controlled trials; 2 follow-up studies; 2 meta-analyses and 6 case reports. We observed an improvement of 20-40% in depressive symptoms, being slightly better in open studies. Five randomized clinical trials displayed positive results. The meta-analyses presented mixed results; although none included the study of Brunoni et al. (2013) that represents almost 50% of the evaluated sample. Open-label studies and case reports also investigated tDCS in bipolar depression, post-stroke depression and employed different parameters of stimulation. Discussion: TDCS is a novel, promising treatment for MDD. Definite evidence from large, ongoing clinical trials will be available in the next years...

Contexto: A estimulação transcraniana por corrente contínua (ETCC) é uma nova intervenção não farmacológica investigada como tratamento no transtorno depressivo maior (TDM). Objetivo: Apresentar uma revisão atualizada da ETCC no TDM. Método: Revisão sistemática no banco de dados Medline/PubMed e outros de todos os estudos clínicos publicados avaliando a eficácia da ETCC no TDM, da primeira data disponível a dezembro/2013. Resultados : De 55 artigos, 24 foram incluídos, sendo 6 estudos abertos; 8 ensaios clínicos randomizados, duplo-cego, placebo controlados; 2 estudos de seguimento; 2 metanálises e 6 relatos de caso. Observa-se uma melhora de 20-40% nos sintomas depressivos, sendo ligeiramente maior nos estudos abertos. Entre os ensaios controlados, 5 demonstraram eficácia da técnica. As metanálises divergiram quanto aos resultados, mostrando presença e ausência de eficácia e ausência da ETCC. Porém, nenhuma incluiu o estudo de Brunoni et al. (2013), que representa quase 50% da população estudada. Estudos abertos e relatos de caso também investigaram o uso da ETCC na depressão bipolar, na depressão pós-AVC e usaram variações nos parâmetros de estimulação. Conclusões: A ETCC é uma técnica promissora no tratamento da TDM. Evidências definitivas devem estar disponíveis nos próximos anos, com a divulgação de resultados de grandes ensaios clínicos em andamento...