Vagus nerve stimulation confuses appetite: comment on Bodenlos et al. (2007)

In a recent research report, [Bodenlos et al. 2007. Vagus nerve stimulation (VNS) acutely alters food craving in adults with depression. Appetite, 48, 145-153] concluded that, in depressed patients, acute activation of a device for VNS caused a significant change in cravings specifically for sweet foods. We argue that there is no evidence for any effect on food cravings. Rather, the findings indicate that VNS confuses the patient's appetite for sweet foods: this might result from contextually unexpected internal afferent signals generated by the vagal stimulation. Unfortunately, their multiple regression of potential predictive variables cannot be interpreted reliably. The concept is interesting, but the design, analysis and interpretation should be reconsidered.