Abstract
Background: Mental illnesses are increasing worldwide with the internalizing disorders (IDs; e.g., anxiety disorders, depressive disorders) being the most prevalent. Current first-line therapies (e.g., pharmacotherapy) offer high failure rates and substantial side effects. Electroencephalographic neurofeedback (EEG-NFB) has been shown to be an effective and safe treatment for these conditions; however, there remains much doubt regarding the existence of specificity (i.e., clinical effects specific to the modulation of the EEG variables of interest). This is a protocol for a quantitative review that will attempt to determine if there is evidence for EEG-NFB specificity in the treatment of IDs. Methods: We will consider all published and unpublished randomized, double-blind (i.e., trainees and raters), sham/placebo-controlled (i.e., feedback contingent on a random signal, the activity from a different person’s brain, or an unrelated signal from the trainee’s own brain) trials involving humans with at least one ID diagnosis without exclusion by language, locality, ethnicity, age, or sex. Effect sizes will be calculated for individual studies and combined in a meta-analysis. Discussion: This protocol outlines the research methodology for a quantitative review undertaken to assess for evidence of EEG-NFB specificity in the treatment of IDs. Registration: This review was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD42020159702).