In clinical trials, almost 500 depression patients who were resistant to current treatments were given therapy that stimulated their vagus nerve. The majority of these patients had such serious depression that they were unable to work. The study showed that after one year, depression symptoms, quality of life, and the ability to do everyday tasks improved in the treated individuals. The findings have been reported in two studies in the journal Brain Stimulation.
In this study, devices were implanted in the participants that specifically stimulated the left vagus nerve. These devices were only turned on in half of the study volunteers, however. Different assessment tools that have been previously validated were then used to analyze the mental health of the participants. There were some significant benefits in those with a device that was turned on.
"These patients are extremely ill, and most have been for a very long time," said Charles R. Conway, MD, a professor of psychiatry at Washington University School of Medicine in St. Louis, and RECOVER trial principle investigator.
"On average, each patient had already tried thirteen treatments that failed to help them before they enrolled in the trial, and they had spent more than half of their lives sick with depression. But despite that super-high level of sustained illness, we still see statistically significant, measurable improvements in depressive symptoms, quality of life and functional outcomes."
Since major depression can cause people to stop performing regular daily functions, the benefits seen in this study may be life-changing, noted Conway. The device may enable people to get out bed in the morning and interact with the world when before they could not.
The Food and Drug Administration (FDA) approved a vagus nerve stimulation device as a therapeutic approach for treatment-resistant depression nearly two decades ago. But it is expensive to implant, so it has not been widely available since insurance typically will not cover the cost.
This study aims to make the device more likely to be cove4red by insurance by proving its efficacy with specific parameters. The Centers for Medicare and Medicaid Services (CMS) needs certain data to make a determination about whether the therapy should be covered by CMS or insurance, and many insurance companies follow the CMS decision. This study was designed with CMS to help pave the way for patients to use this treatment, and have it covered by insurance.
The implant works with a device that is put into the skin of the chest. A wire then links the left vagus nerve to the device, and the stimulation that is delivered to the vagus nerve sends electrical impulses to the brain. These impulses reach a region that is related to mood regulation.
Complete remission of depression was rare in both groups, but those who had devices that were turned on reported significant improvements in function and quality of life.
"What's really important here is that patients themselves were reporting that their lives were improving," Conway said. "You have a population of people that has been failed by a ridiculously high number of treatments, including very aggressive treatments such as electroconvulsive therapy."
The study will continue to follow the participants and their outcomes for four years to learn more about how much benefit the device can deliver.
Sources: Washington University in St. Louis, Conway et al Brain Stimulation 2024, Rush et al Brain Stimulation 2024
