The Efficacy of transcranial Direct Current Stimulation (tDCS) on Emotional Processing

Abstract While some research has reported the positive impacts of transcranial direct current stimulation (tDCS) on emotional processing, the conflicting results and variations in study quality and design make it challenging to draw firm conclusions about its effects. To address this issue, we conducted a meta-analysis of the published literature on tDCS effects on emotional processing. We evaluated the effects of anodal and cathodal tDCS on emotional processing by analyzing a total of 32 articles and a combined sample of 2,107 participants. Our study illustrates the significant effects of both anodal and cathodal tDCS on emotional processing. The results highlight significant differences in how tDCS stimulation parameters influence emotional processing, demonstrating that frontal tDCS enhances emotional outcomes more effectively than stimulation of other brain regions. Key findings include that longer stimulation durations (over 20 minutes) and higher current intensities (2 mA) yield better results, with online tDCS being more effective than offline stimulation, particularly in younger participants and in non-clinical populations. Our results reveal that tDCS can effectively enhance emotional processing, offering valuable insights into the potential benefits of this method for emotion improvement. Competing Interest Statement The authors have declared no competing interest. Funding Statement No Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes The name of correspondin author was changed Data Availability The datasets supporting the conclusions of this article are included in the supplementary file.