Electrically stimulating the brain's "reward" circuity may hold promise as a treatment for binge eating disorder, a small pilot study suggests.
The findings are based on just two patients who received deep brain stimulation (DBS) -- a technique used for certain other medical conditions, including epilepsy. But over six months, the approach was able to reduce the patients' "loss of control" eating -- so much so that one patient no longer met the criteria for binge eating disorder.
Experts were encouraged by the initial success, and said it strengthens the evidence that binge eating is a brain-based disorder.
"This has nothing to do with willpower," said Stuart Murray, director of the Eating Disorders Program at the University of Southern California's Keck School of Medicine.
Murray, who was not involved in the new research, noted that binge eating disorder is the most common type of eating disorder, yet the least studied.
"This is probably the most exciting paper I've seen in years," he said of the report, published Aug. 29 in the journal Nature Medicine.
The findings in the two patients showed that prior to bingeing episodes, there was abnormal electrical signaling in a small brain area called the nucleus accumbens -- which is involved in reward-seeking and impulse control. Disrupting those signals with the brain stimulation device reduced the patients' binges.
That clearly shows that abnormal signaling in the nucleus accumbens is "heavily involved" in people's vulnerability to bingeing, said senior researcher Dr. Casey Halpern, an associate professor of neurosurgery at the University of Pennsylvania.
Like Murray, he stressed that people with binge eating disorder struggle with impulse control, but it's not a moral failing.
"This is a neurological condition that involves abnormal brain wiring," Halpern said. "It's not the patient's fault."
Binge eating disorder has been estimated to affect up to 5% of Americans. People with the condition regularly eat large amounts of food in a short time span, and feel they cannot control what or how much they are consuming. They also commonly are obese.
The standard treatments include "talk therapies" aimed at the negative thoughts and behaviors that fuel binge eating, as well as medication.
But those treatments are effective only about half the time, Murray noted.
The exact causes of binge eating disorder aren't clear, but research is increasingly pointing to underlying brain abnormalities. In a recent study, Murray found that children with binge eating disorder show structural differences in certain brain areas related to reward and impulsivity, compared with kids without the disorder.
Similarly, Halpern and his colleagues have been zeroing in on the brain basis for binge eating. In prior research with lab mice, they found that stimulating the nucleus accumbens reduced the animals' food cravings and allowed them to resist tempting, high-calorie treats.
"Targeting the brain to treat binge eating disorder makes a lot of sense," Murray said.
To test that premise, Halpern's team recruited two patients with binge eating disorder and severe obesity that had resisted standard treatments -- including weight-loss surgery. Both women were fitted with a DBS device that is approved for treating epilepsy.
The device is implanted under the scalp, with wires that run through the skull to deliver electrical pulses to a brain area where electrical signaling is going awry.
In the first phase of the study, the DBS device recorded activity in each patient's nucleus accumbens. It confirmed that a distinctive "low frequency" signal arose just before the women's binge eating episodes. Then in the next phase, the DBS device was set to automatically disrupt those electrical signals when they arose.
That way, Halpern explained, the DBS stimulation was not continuous, but only delivered as needed.
Over six months, both patients reported improvements in their feelings of loss of control, while their bingeing episodes dropped substantially. Weight also decreased: one woman lost 13 pounds and the other went down 18 pounds.
There is still much work ahead, Halpern stressed. The researchers are continuing to follow the two patients, and are enrolling several new patients.
Among the future questions is whether other brain circuits are also involved in binge eating, and could stand as treatment targets -- a likely scenario, both Halpern and Murray said.
"I think we're just beginning to scratch the surface," Halpern said.
He also noted that problems with impulse control are central to many other conditions, like addiction and obsessive-compulsive disorder -- raising the possibility that a similar treatment approach could be applied to them, as well.
The study was funded by the U.S. National Institutes of Health.
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more on binge eating disorder.
SOURCES: Casey Halpern, MD, associate professor, neurosurgery, Perelman School of Medicine, University of Pennsylvania, and chief stereotactic and functional neurosurgery, Penn Medicine and the Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia; Stuart Murray, PhD, associate professor, psychiatry, and director, Eating Disorders Program, Keck School of Medicine, University of Southern California, Los Angeles; Nature Medicine, Aug. 29, 2022