Effectiveness of Deep Brain Stimulation in Treatment of Anorexia Nervosa and Obesity: A Systematic Review

OBJECTIVE: Anorexia nervosa and obesity are common appetite disorders, which may be life threatening if not treated and often coincide with psychiatric disorders. We sought to investigate whether deep brain stimulation (DBS) of specific regions within the brain could aid in the treatment of these disorders. This review aims to organize the literature regarding the feasibility of DBS via clinical outcomes and synthesize the data on patient demographics and electrode parameters for future optimization. METHODS: PubMed, Scopus, and Web of Science databases were all queried on 7 June 2022 to identify studies reporting the effect of DBS in treatment of either anorexia nervosa or obesity. We included studies involving 1) DBS, 2) treatment of anorexia nervosa or obesity, and 3) body mass index (BMI) as the primary outcome variable. Case reports, retrospective cohort studies, and randomized controlled trials were all eligible for inclusion. Exclusion of articles was based on the following criteria: 1) meta-analyses or systematic reviews or 2) describes diseases other than only anorexia or obesity. Screening of the 999 articles returned by an initial search yielded 23 studies for inclusion and further data extraction. Qualitative assessment of included studies was subsequently conducted in accordance with Newcastle-Ottawa Scale criteria. RESULTS: We included 23 articles (17 anorexia, 5 obesity) that met our inclusion and exclusion criteria, which included 8 case reports, 13 case series, and 1 case-control study. Our primary variables of interest were location of DBS, change in BMI after intervention, electrode parameters, and psychiatric comorbidities. A total of 131 patients were included and analyzed, 118 of those belonging in the anorexia cohort. For patients with anorexia, we found that the most common place for DBS was the subcallosal cingulate followed by the nucleus accumbens, resulting in an overall increase in BMI by 24.82% over the span of a mean 17.1 months. Psychiatric comorbidities (major depressive disorder, obsessive-compulsive disorder, and anxiety) were common in the anorexia cohort. For patients with obesity, DBS was most common in the lateral hypothalamus followed by the nucleus accumbens, resulting in a small decrease in BMI by 3.97% over a mean 17.2 months. Data were insufficient for this cohort to report on additional psychiatric comorbidities or calculate the duration from diagnosis to treatment. CONCLUSIONS: DBS seems to be a promising solution in addressing treatment-refractory anorexia, but additional prospective studies are still needed to confirm this same usefulness for the treatment of obesity. Primary limitations included the apparent lack of data on DBS for obesity as well as the dearth of cohort studies assessing efficacy of DBS compared with control treatments. Although these limitations could not be addressed in the current review, this study may incentivize future trials to assess DBS in patients with appetite disorders in a more controlled fashion.