The device may be especially helpful 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 the 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 medications that pretty much do the same thing,” Dr. Aaronson said. And when patients don’t respond to those drugs, “we don’t have much news.”
However, vagus nerve stimulation is currently not accessible to most people because 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 internal vagus nerve stimulation to treat inflammation, may also have applications for psychiatric disorders such as PTSD, said Andrew H. Miller, MD, director of the Behavioral Immunology Program at Emory University, which studies how the brain and immune system interact, and how those interactions can contribute to stress and depression.
PTSD is characterized by increased measures of inflammation in the blood, he said, which “can influence circuits in the brain that are related to anxiety.”
In a pilot study at Emory, for example, researchers electronically stimulated the skin of the neck near the vagus in 16 people, eight of whom received vagus nerve stimulation treatment and eight of whom received sham treatment. The researchers found that stimulation treatment reduced inflammatory responses to stress and was associated with decreased PTSD symptoms, indicating that stimulation may be helpful for some patients, including those with elevated inflammatory biomarkers.
In the meantime, Dr. Porges and colleagues at the University of Florida have patented a method for adjusting electrical stimulation of the vagus nerve based on the patient’s physiology. He is now working with the company Evren Technologies, of which he is a shareholder, to develop an external medical device that uses this approach for PTSD patients.
