Brain stimulation in obesity

Obesity is taking up epidemic proportions worldwide with significant impacts on the health of both the affected individual and on society as a whole. Treatment approaches consist of behavioural and pharmacological approaches, however, these are often found to be ineffective. In severe obesity, bariatric surgery is frequently performed. Unfortunately, 40% of patients show substantial weight gain over the long term or display the associated metabolic syndrome, making the development of novel therapies necessary. This review summarizes some of the current conceptual models, in particularly the 'food addiction' model, and then discusses specific therapeutic targets of brain stimulation, both non-invasive (transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and transcutaneous vagus nerve stimulation (VNS)) and invasive (deep brain stimulation and invasive VNS). As we will show, neuromodulatory approaches represent a promising tool for targeting specific brain structures implicated in the pathophysiology of obesity. Non-invasive techniques such as TMS, tDCS and transcutaneous VNS need further investigation before they may become ready for clinical usage. The currently available study data suggest that deep brain stimulation may become an effective and acceptable therapy for otherwise treatment-resistant obese patients. The results of the currently undergoing clinical trials are eagerly awaited.