Psychiatry’s New Frontier: Brain Stimulation
Wayne K. Goodman, MD, discusses growing interest in the use of deep brain stimulation to treat intractable psychiatric disorders, and why we need to proceed cautiously
Over the last decade, the use of neurosurgical treatments for severe psychiatric disorders has increased dramatically with the advent of deep brain stimulation (DBS). The surgical procedure, which involves implanting a device that delivers electrical stimulation directly to the brain, is thought to affect behavior by modulating the patterns of neural activity underlying neurological disorders. DBS is currently the surgical standard of care for treating severe cases of medication-resistant movement disorders like Parkinson’s disease, Essential tremor and Dystonia. Performed in more than 75,000 patients worldwide, the procedure has obviated the need for ablative (lesioning) neurosurgery. In contrast to ablative procedures, DBS is adjustable and potentially reversible.
The first published report of DBS being used to treat a psychiatric condition occurred in 1999 in four cases of intractable Obsessive-Compulsive Disorder (OCD). Since that time, according to published reports, approximately 100 cases of OCD and approximately 50 cases of treatment-resistant depression (TRD) have been treated with DBS for seven different brain targets. The results for some anatomic targets, while still a small sample size, have been promising. Even though the studies differed in design and methodology, in patients with OCD, the overall treatment response rate exceeded 50 percent for some targets (e.g., ventral capsule/ventral striatum). In TRD, the response rates to acute and long-term DBS also exceeded 50 percent for one target, the subcallosal cingulate gyrus.
At Mount Sinai, we have treated six patients with intractable OCD using DBS since 2009. In the operating room, I work closely with our new neurosurgeon Brian Kopell, MD, Associate Professor and Co-Director of the Center for Neuromodulation, who implants the various components of the device. During surgery, my role is to test the emotional and behavioral effects of the device when the patient is awake. Prior to joining Mount Sinai, Dr. Kopell led a team that performed more than 400 DBS procedures for movement disorders. He also pioneered the use of intraoperative imaging during DBS surgery, which supplements the microelectrode recording that is used to ensure the procedure is safe and timely for patients.
Thankfully, this emerging field of psychiatric neurosurgery has the benefit of drawing upon more than 20 years of research on DBS in movement disorders. As a result, we know a great deal about the safety of the device and its performance characteristics. After the surgery, a psychiatrist monitors the patient on repeated visits and can adjust the settings of the device as needed, using a handheld programmer.
Despite its possible benefits, there are also significant risks associated with DBS, particularly the initial surgery, including hemorrhage (approximately 2 percent of cases) and infection (approximately 4-5 percent of cases). Thus, the procedure should be reserved for patients with severe treatment-resistant psychiatric illness in the context of a robust informed consent process that includes alternatives to DBS.
As we usher in this new era in psychiatric neurosurgery, researchers must assure the public that history will not repeat itself. Our field has learned from the abuses of the 1940s when frontal lobotomies were crudely and cavalierly administered to more than 18,000 patients in the United States alone. Even though studies have shown that DBS is typically well tolerated in OCD and TRD patients thus far — there have been some target-specific reports of adverse effects like hypomania — further research is needed to thoroughly test both the efficacy and safety of the procedure and ensure our moral imperative of “first do no harm.”
The long-term value of DBS in psychiatry may be to help elucidate the neurocircuitry of emotional regulation. As we understand how different nodes in the circuit affect brain function, we will not only refine the targeting of DBS, but hopefully also develop new, nonsurgical interventions.
Wayne K. Goodman, MD
Chair of the Department of Psychiatry
Esther and Joseph Klingenstein Professor of Psychiatry
The Mount Sinai Medical Center