The device may be particularly useful for people with bipolar depression because there are so few treatments for them, said Dr. Scott Aaronson, one of the lead psychiatrists involved in the clinical trial and scientific director of the Institute for Advanced Diagnostics and Therapeutics, a center within Sheppard Pratt Psychiatric Hospital that aims to help people who have not improved with conventional treatments and medications.
In general, one of the problems with treating depression “is that we have a lot of drugs that do pretty much the same thing,” Dr. Aaronson said. And when patients don’t respond to these drugs, “we don’t have a lot of new stuff.”
However, implanted vagus nerve stimulation is not currently available to most people, as insurers have so far refused to pay for the procedure, with the exception of Medicare beneficiaries participating in the latest clinical trial.
Dr. Tracey’s research, which uses stimulation of the internal vagus nerve to treat inflammation, could also have applications for psychiatric disorders like PTSD, said Dr. Andrew H. Miller, director of the Emory University’s Behavioral Immunology Program, which studies how the brain and immune system interact, and how these interactions can contribute to stress and depression.
PTSD is characterized by heightened measures of inflammation in the blood, he said, which “may influence anxiety-related brain circuitry.”
In a pilot study at Emory, for example, researchers electronically stimulated the neck skin near the vagus nerve in 16 people, eight of whom received vagus nerve stimulation treatment and eight received sham treatment. Researchers found that stimulation treatment reduced inflammatory responses to stress and was associated with reduced PTSD symptoms, indicating that such stimulation may be useful for some patients, including those with elevated inflammatory biomarkers. .
Meanwhile, Dr. Porges and colleagues at the University of Florida have patented a method to adjust electrical stimulation of the vagus nerve based on patient physiology. He is now working with the company Evren Technologies, in which he is a shareholder, to develop an external medical device that uses this approach for patients with PTSD.