A "pacemaker-in-the-brain" may provide an effective last-resort treatment for anorexia, research has shown.
Doctors used electric pulses delivered deep into the brain to prevent weight loss in several women who had suffered the eating disorder for decades.
Although the pilot trial was only designed to assess safety, the results suggest the technique might offer new hope to the most seriously affected patients.
Up to a fifth of people with anorexia nervosa fail to respond to conventional treatment and are at risk of dying from starvation or infection.
Death rates can be as high as 15% and a further 15-20% of patients develop a chronic and unresponsive condition.
The new therapy is a form of Deep Brain Stimulation (DBS) that has already shown success in treating Parkinson's disease and depression.
Six women aged 24 to 57 took part in the trial. They had been suffering from anorexia for between four and 37 years. All had stopped responding to other forms of treatment, and had a history of complications and hospital admissions.
Under local anaesthetic, surgeons implanted electrodes into a part of the brain linked to mood and depression. These were connected by concealed wiring to a pacemaker-like generator hidden under the skin just below the collar bone.
Three months after after the procedure, five patients had started to keep their weight constant or gained weight.
After nine months, three were maintaining a higher weight than they had when the treatment began. This was the longest period of sustained weight increase any had achieved since they fell ill.
Four of the six patients also experienced changes in mood, anxiety, control over emotional responses, urges to binge eat and purge and other anorexia symptoms such as obsessions and compulsions.
The findings are published today in The Lancet medical journal.
Lead researcher Dr Andres Lozano, from the Krembil Neuroscience Centre in Toronto, Canada, said: "We are truly ushering in a new of era of understanding of the brain and the role it can play in certain neurological disorders.
"By pinpointing and correcting the precise circuits in the brain associated with the symptoms of some of these conditions, we are finding additional options to treat these illnesses."
Co-author Professor Blake Woodside, from the University of Toronto, said: "There is an urgent need for additional therapies to help those suffering from severe anorexia.
"Eating disorders have the highest death rate of any mental illness and more and more women are dying from anorexia.
"Any treatment that could potentially change the natural course of this illness is not just offering hope but saving the lives for those that suffer from the extreme form of this condition."
Only one patient suffered a serious side effect, a seizure. This was related to a metabolic disorder caused by anorexia.