Some women with severe anorexia have returned to a healthy weight and feel less anxious and depressed after having electrical devices implanted into their brains, according to a small study. But more research is needed before the treatment can be recommended for wider use.
About one in five people with anorexia nervosa, who are mostly women, die of the illness and there is a lack of effective treatments. Imaging studies suggest that certain brain circuits may underlie the fear of gaining weight and compulsion to self-starve.
Bomin Sun at Shanghai Jiao Tong University School of Medicine in China and his colleagues wondered whether they could disrupt these circuits by electrically stimulating a part of the brain known as the nucleus accumbens. This brain region helps us to learn from experience, but in people with anorexia it seems to form abnormal connections with other brain regions.
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The team recruited 28 women with at least a three-year history of anorexia who hadn’t improved following standard treatment. The women had an average body mass index (BMI) of 13; a BMI of less than 18.5 is considered underweight. The researchers surgically implanted electrodes into the nucleus accumbens on both sides of the women’s brains. They connected the electrodes by wires to a battery inserted beneath the collarbone, to continuously stimulate the nucleus accumbens.
Over the next two years, the average BMI of the participants increased to 18 and almost half regained a BMI of 18.5 or above. They also reported feeling fewer anxiety and depression symptoms and experiencing less of an effect on their social lives.
Placebo effect?
“This is a very promising result,” says Philip Mosley at QIMR Berghofer Medical Research Institute in Australia. But the study didn’t include a placebo group for comparison, meaning it isn’t possible to rule out that the participants’ improvement was simply because they expected the treatment to work, says Mosley.
He and his colleagues are about to launch a trial of the same treatment in which they will control for the placebo effect. They will implant electrodes into the nucleus accumbens of 10 people with severe anorexia, but for the first four months, only half will have the electrodes switched on. Participants won’t know if their electrodes are on or off. If the improvement is greater when the electrodes are on, it will make it easier to tell if the treatment is working.
Brain surgery may seem like an extreme treatment, but for people with severe anorexia, it may be better than the alternative, which is often death, says Mosley.
“Anorexia has the highest mortality rate of any psychiatric illness – it’s an astonishingly sinister disease,” he says. “We hope this treatment will help some people who are at the sickest end of the scale and had years of suffering and tried all other evidence-based treatments.” ❚
Brain Stimulation
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