How much can a nerve running from the brain to the stomach affect how you feel? Researchers are discovering that this nerve, known as the vagus nerve, has a significant impact on the symptoms of disorders like depression and anxiety. Evidence shows that stimulating the vagus nerve, a process called vagus nerve stimulation (VNS) can reduce depressive symptoms. A new study from the China Academy of Chinese Medical Sciences, in collaboration with Harvard Medical School, has proven that a safer method of VNS is effective for alleviating the symptoms of depression.
Traditional VNS is a treatment that requires neurosurgery to place an implant in the patients’ brain. Although the treatment has proven beneficial, this type of VNS is risky and can result in problematic, even disabling side-effects.
The new study tested a form of non-invasive VNS, which eliminates the need for challenging surgery. For this study, the researchers used a form of VNS called transcutaneous VNS. This method stimulates the vagus nerve via electrodes that sit in the ear like headphones. The researchers tested this method on a group of patients with major depressive disorder. Some of the patients received treatment, while a control group received a placebo. The researchers also conducted functional neuroimaging scans of the patients before and one month after the treatment.
Non-invasive VNS helped the patients to overcome depressive symptoms. The patients who received the treatment demonstrated significant improvements in their symptoms compared to the control group. The neuroimaging data revealed that the improvements in symptoms were associated with increased functional connectivity between the brain’s default mode network (involved in thinking about the self, others, and future plans) and the precuneus (involved in memory and the sense of self) and orbital prefrontal cortex, which is known to be altered in depression.
Study researcher Dr. Peijing Rong of the China Academy of Chinese Medical Sciences concludes, “This non-invasive, safe and low cost method of depression treatment can significantly reduce the severity of depression in patients and shows promise for the future.”
This research is published in the journal Biological Psychiatry.
For further information on the vagus nerve and the polyvagal theory, listen to the podcast with Dr. Stephen Porges.