Abstract
Objective: Personality disorders are serious psychiatric conditions, and some studies have examined neurofeedback training as a potential alternative treatment to improve cognitive and clinical symptoms in patients with such disorders. Here, we aimed to provide a first systematic review of such trials and present existing evidence regarding this treatment for individuals with personality disorders. Method : A systematic search of peer-reviewed English journal articles was conducted for this study to identify original studies on fMRI and EEG neurofeedback treatment protocols in patients with personality disorders up to January 2023. PubMed, Web of Science, ProQuest, Cochrane Library, and Google Scholar databases were queried through the keywords "neurofeedback," "biofeedback," and "personality disorder," as well as their related Mesh synonyms. Results: Totally, five studies were included in our systematic review. Two studies utilized EEG neurofeedback protocols, while three articles used real-time fMRI neurofeedback protocols. The types of studies were non-randomized, not-blinded case reports, case series, and single-arm trials with a high risk of bias. EEG neurofeedback protocols applied more training sessions and reported improvements in patients' neuropsychological and behavioral functions after treatment. Furthermore, fMRI-based neurofeedback studies reported neurophysiological changes, such as a shift in vmPFC-amygdala connectivity, towards healthy states following treatment. Moreover, behavioral symptoms of patients were reported to be improved after fMRI neurofeedback. Conclusion: Neurofeedback studies investigating this therapeutic technique for personality disorders are still very preliminary, and no strict conclusions can be drawn at this time. Therefore, further basic and clinical investigations are required to address several open methodological and technical questions and establish consensus and standardization, which will eventually lead to translational works.