The Efficacy of Bio- and Neurofeedback for Depression: A Meta-analysis
For many years, biofeedback and neurofeedback have been implemented in the treatment of depression. However, the effectiveness of these techniques on depressive symptomatology is still controversial. Hence, we conducted a meta-analysis of studies extracted from PubMed, Scopus, Web of Science and Embase.Two different strings were considered for each of the two objectives of the study: A first group comprising studies with Major Depressive Disorder (MDD) patients and a second group including studies targeting depressive symptomatology reduction in other mental or medical conditions.In the first group of studies including MDD patients, the within-group analyses yielded an effect size of Hedges’ g = 0.717, while the between-group analysis an effect size of Hedges’ g = 1.050. Moderator analyses indicate that treatment efficacy is only significant when accounting for experimental design, in favor of RCTs in comparison to non RCTs, whereas type of neurofeedback, trial design, year of publication, number of sessions, age, gender and quality of study did not influence treatment efficacy. In the second group of studies, a small but significant effect between groups was found (Hedges’ g = 0.303) in favor of bio- and neurofeedback against control groups. Moderator analyses revealed that treatment efficacy was not moderated by any of the sociodemographic and clinical variables.HRV Biofeedback and Neurofeedback are associated with a reduction in self-reported depression. Despite the fact that the field has still a large room for improvement in terms of research quality, the results presented in this study suggests that both modalities may become relevant complementary strategies for the treatment of MDD and depressive symptomatology in the coming years.