Efficacy of Repetitive Transcranial Magnetic Stimulation (rTMS) in the Treatment of Bulimia Nervosa (BN): A Review and Insight into Potential Mechanisms of Action

Abstract

Introduction: Bulimia nervosa (BN) is a disorder primarily affecting adolescent females, characterized by episodes of binge eating followed by inappropriate compensatory behaviors aimed at preventing weight gain, including self-induced vomiting and the misuse of diuretics, laxatives, and insulin. The precise etiology of BN remains unknown, with factors such as genetics, biological influences, emotional disturbances, societal pressures, and other challenges contributing to its prevalence. First-line treatment typically includes pharmacotherapy, which has shown moderate effectiveness. Neuroimaging evidence suggests that altered brain activity may contribute to the development of BN, making interventions that directly target the brain extremely valuable. One such intervention is repetitive transcranial magnetic stimulation (rTMS), a non-invasive stimulation technique that has been garnering interest in the medical community for many years.

Methods: This review explores the use of rTMS in the treatment of BN. Searches were conducted in the PubMed/Medline, ResearchGate, and Cochrane databases.

Results: Twelve relevant studies were identified. Analysis of the results from these studies reveals promising findings, particularly regarding key parameters in the pathophysiology of BN. Several studies assessed the impact of rTMS on binge episodes. While some studies did not find significant reductions, most reported decreases in binge eating and purging behaviors, with some cases showing complete remission. Reductions in symptoms of depression and food cravings were also demonstrated. However, results regarding cognitive improvement were mixed. The discussion focused heavily on potential mechanisms of action, including neuromodulation of brain networks, induction of neuroplasticity, impact on serotonergic dysfunction, anti-inflammatory action, and HPA axis modulation. rTMS was found to be a safe intervention with no serious side effects.

Conclusions: rTMS in the treatment of BN appears to be a promising intervention that alleviates some symptoms characteristic of the pathophysiology of this disorder. An additional effect is a significant reduction in depressive symptoms. However, despite these findings, further research is required to confirm its effectiveness and elucidate the mechanisms of action. It is also recommended to further investigate the potential mechanisms of action described in this review.

Keywords: bulimia nervosa; eating disorders; neuromodulation; neurostimulation; non-invasive brain stimulation; rTMS; repetitive transcranial magnetic stimulation.

Figure 1

Flow chart depicting the different phases of the systematic review.

Figure 2

Cortical structures stimulated in the included studies. Left DLPFC stimulated in 11 studies: [34,35,36,37,38,39,40,41,42,43,45]. Bilateral DMPFC stimulated in 1 study: [44].