A Systematic Review on the Acceptability and Tolerability of Transcranial Direct Current Stimulation Treatment in Neuropsychiatry Trials.
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation investigated as a treatment for several neuropsychiatric disorders. Notwithstanding tDCS-induced adverse events (AEs) are considered to be low and transient, systematic review analyses on safety and tolerability of tDCS derive mostly from single-session studies.



To investigate the tolerability (rate of AEs) and acceptability (rate of dropouts) of tDCS.



Systematic review and meta-analysis of tDCS randomized, sham-controlled trials in healthy or neuropsychiatric adult samples from the first date available to March 9, 2016. We only included parallel studies performing at least 5 tDCS sessions. An adapted version of CONSORT guidelines for reporting harms outcomes was used to evaluate AE reporting.



Sixty-four studies (2262 participants) were included. They had a low risk of publication bias and methodological bias for the items assessed. Dropout rates in active and sham tDCS groups were, respectively, 6% and 7.2% (OR = 0.82 [0.59-1.14]). However, almost half of studies reported no dropouts and only 23.4% reported its reasons; when reported, the most frequent reasons were AEs and protocol violation. A tolerability meta-analysis was not performed, as most studies did not report AEs. The quality of AEs reporting was also limited, particularly in smaller studies and stroke studies.



Although overall dropout rate was low and similar in active and sham groups, studies did not adequately describe AEs. An updated questionnaire and guidelines for assessment of AEs in tDCS trials are proposed in order to standardize the reporting of AE in the field.
Center for Clinical and Epidemiological Research & Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil; Service of Interdisciplinary Neuromodulation (SIN), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.
Luana V M
LVM
Aparício
Center for Clinical and Epidemiological Research & Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil; Service of Interdisciplinary Neuromodulation (SIN), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.
Fabiana
F
Guarienti
Center for Clinical and Epidemiological Research & Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil; Service of Interdisciplinary Neuromodulation (SIN), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.
Lais Boralli
LB
Razza
Department of Psychiatry and Translational Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
André F
AF
Carvalho
Laboratory of Neuromodulation, Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard University, USA.
Felipe
F
Fregni
Center for Clinical and Epidemiological Research & Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil; Service of Interdisciplinary Neuromodulation (SIN), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil; Laboratory of Neuroscience (LIM27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil. Electronic address: brunoni@usp.br.
André Russowsky
AR
Brunoni
D002986:Clinical Trials as Topic; D006801:Humans; D059408:Pain Management / Q000379:methods; D000071939:Stroke Rehabilitation / Q000009:adverse effects* / Q000379:methods; D011795:Surveys and Questionnaires; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects* / Q000379:methods
Acceptability; Adverse effects; Meta-analysis; Tolerability; Transcranial direct current stimulation