EEG Neurofeedback for Major Depressive Disorder: A Scoping Review.

Neurofeedback (NF) is an emerging treatment for Major Depressive Disorder (MDD). NF is a training approach that enables individuals to self-regulate brain activity patterns associated with emotional and cognitive dysfunction. While interest is increasing, research results vary, and clinical implementation does not follow standardized protocols. This scoping review aimed to map and synthesize the existing peer-reviewed evidence on electroencephalography (EEG)-based neurofeedback interventions for MDD, with a focus on training protocols, neurophysiological targets, reported clinical outcomes, and methodological limitations. A systematic scoping review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines (OSF registration): https://doi.org/10.17605/OSF.IO/NQ3BW. Electronic searches were performed across Embase, PubMed, Web of Science, and ClinicalTrials.gov. Studies were included if they evaluated EEG-based neurofeedback interventions in adults with MDD and reported clinical or neurophysiological outcomes. Of 1299 records identified, 11 studies met the inclusion criteria, encompassing outcome data from 175 patients who received active EEG-NF. The studies observed a reduction in depressive symptoms following neurofeedback, most commonly using frontal alpha asymmetry protocols (k = 5). Potential improvements in cognitive performance were reported in 4 studies, particularly those incorporating upper-alpha or beta/theta modulation. Connectivity-based approaches using low-resolution electromagnetic tomography Z-score neurofeedback (low-resolution electromagnetic tomography (LORETA); k = 2) suggested possible effects on deep brain networks involved in emotional regulation, though replication remains limited. This scoping review outlines the existing evidence on EEG-based neurofeedback in major depressive disorder, highlighting the diversity of protocols, targets, and reported outcomes. While preliminary findings suggest potential clinical relevance, substantial methodological limitations and heterogeneity remain. These observations emphasize the need for more rigorous, standardized, and longitudinal research to better define the role of EEG-based neurofeedback in the treatment of MDD.