Surgically implanting a pacemaker into the brains of severe anorexia patients may help treat their symptoms.

The neurosurgical implant was used safely for the first time in six patients with severe and enduring anorexia after receiving no benefits from other known treatments.

The results were published in the journal The Lancet.

The procedure, referred to as deep brain stimulation (DBS), involves a device comparable to a pacemaker that becomes implanted into the brains of patients with anorexia.

Anorexia Nervosa is a psychological disorder in which the person has a distorted body image and an illogical fear of becoming or being overweight, so they intentionally strive to lose weight. Most patients with the disorder are female, but men can sufferer from it as well.

Although the pilot study was essentially focused on evaluating the safety of the technique, at least 50% of the patients who were involved in the trial demonstrated improvements in mood and BMI (body mass index).

Therefore, larger studies will hopefully verify the efficacy of the procedure in treating severe anorexics.

DBS is currently used to treat a number of neurological disorders, such as chronic pain and Parkinson’s disease. Results of a two-year clinical trial showed that DBS improves overall quality of life and social functioning in patients in earlier stages of Parkinson’s disease.

Scientists are now conducting trials to examine its use for other disorders, such as epilepsy and depression. Researchers believe that obesity could be treated using DBS as well.

However, this is the first time that DBS has been used for the treatment of anorexia patients who have not responded to other therapies.

Although some surgery is needed, the experts explained, the treatment is minimally invasive and entirely reversible.

For the purpose of the research, scientists based at the Krembil Neuroscience Centre and University Health Network in Canada used MRI (Magnetic Resonance Imaging) to pinpoint a certain part of the brain – a bundle of white matter beneath the corpus callosum, the thick bundle of nerve fibres dividing the left and right sides of the brain – which has been used in the past for DBS in individuals with depression.

After the experts found the target area, they then implanted electrodes into the area and connected them to a pulse generator that was implanted under the skin.

Ten days after implantation, the device was activated. Acute changes in the mood and anxiety levels of the patients were carefully measured in order to establish the precise level of stimulation.

The female participants were between the ages of 24 and 57 at the time of the procedure. The patients had been struggling with anorexia for between 4 and 37 years.

Although the safety of the surgery was the main focus, the experts also used standardized tests to record alterations in the volunteers’:

  • mood
  • abnormal eating patterns
  • compulsive behavior

Results showed that the treatment was “relatively safe”. However, one patient experienced a severe negative outcome after the treatment – a seizure which occurred approximately 14 days after the initial operation, which was associated with a metabolic disorder she had developed due to her anorexia.

Five of the 6 participants started to attend impatient treatment in the weeks prior to surgery, which caused them to gain some weight.

All of the patients had experienced weight loss after 2 months, returning to their normal baseline.

The results were in line with the scientists’ expectations because reports of DBS for people with depression have normally shown that the treatment does not become effective until a few months later.

“However, three months after the treatment, this pattern began to reverse, with five of the six patients stabilizing or gaining weight, relative to two months after the operation,” the researches pointed out.

Three patients were able to maintain their weight higher than before the treatment began, which was the longest period of sustained increase in weight that any of the subjects had accomplished since the disease’s onset.

About 50% of the participants also improved their mood or and experienced less obsessive-compulsive behavior.

The findings are especially motivating because they appear to indicate a genuine therapeutic effect, instead of a placebo or hunger-increasing effect, said one of the lead investigators Dr Andres Lozano, a leading neurosurgeon in the field of DBS.

Dr Lozano explained:

“The initial weight loss argues against a primary effect of DBS on hunger, appetite, or metabolic rate. It also suggests that there is little in the way of a placebo-related benefit to the surgery. The finding of improvements in mood and anxiety in patients who were still underweight is especially striking, in view of the well known poor response of underweight patients to conventional pharmacotherapies or psychotherapies.”

Of all of the psychiatric disorders, anorexia has one of the highest mortality rates. It is also one of the most prevalent psychiatric disorders among female adolescents between 15 and 19 years old.

Treatment is typically aimed at changing behavior, however, about 20% of patients do not derive any benefits from it. This is devastating, because the disease is putting them at risk of dying prematurely.

In a linked Comment, Professor Janet Treasure and Professor Ulrike Schmidt of King’s College London’s Institute of Psychiatry wrote:

“the personal and social costs of eating disorders in general are large, and nowhere are these more evident than in patients with severe and enduring anorexia nervosa. New effective treatments for these patients are sorely needed…the findings of this proof-of-concept study are promising and will give hope to patients with especially pernicious forms of the disorder and their families. The fact that the procedure was associated in some patients with improvements in affective and obsessional symptoms is of key importance, since such improvements will go some way towards reassuring patients that DBS is not just another treatment designed to fatten them up without making them feel better.”

Written by Sarah Glynn