What
if an uncontrollable urge to rapidly eat large amounts of food is rooted in an
impaired brain circuit? If that were the case, people who live with binge
eating disorder — a psychiatric diagnosis — might be no more at fault for
overeating than a patient with Parkinson’s disease is for their tremors.
اضافة اعلان
That question
led doctors to try a new treatment different from anything ever attempted to
help people with this common but underreported eating disorder. At least 3
percent of people have it, said Dr Casey Halpern, a neurosurgeon at the
University of Pennsylvania.
He and his
colleagues decided to try deep brain stimulation, a method routinely used to
quell tremors in patients with
Parkinson’s. It involves placing electrodes in
the brain to regulate aberrant signals. The wires, connected to the electrodes,
are placed under the scalp, where they are invisible and unobtrusive. For the
binge eating treatment, the device only stimulates neurons when the device
detects a signal to start a binge.
The pilot study,
funded by the US National Institutes of Health and published earlier this year
in the journal Nature Medicine, involves two women and will be expanded in a
few months to include four more people living with binge eating disorder who
regained the weight they lost after bariatric surgery. Before the treatment can
be approved by the Food and Drug Administration, researchers will need to
rigorously test the method in at least 100 people in multiple medical centers.
Such a study would take several years to complete.
The two women
whose devices were implanted a year ago will be followed for up to three years.
They had the option to have their devices removed after 12 months, but both
wanted to keep them because they no longer felt irresistible urges to binge.
One of them,
Robyn Baldwin, 58, of Citrus Heights,
California, described herself as a
“chunko child” who had “always been big”. She tried a wide range of diets.
Once, she consumed only protein shakes for a month.
In 2003, she had
bariatric surgery, which usually involves altering the digestive system so that
the stomach is smaller and food is more difficult to digest. It has enabled
many people to lose weight when other methods failed. But for Baldwin, the
weight she lost came back.
Lena Tolly, 48,
the other patient from the study, lives in Sacramento, California. She also
tried a large number of diets and remedies for obesity. Her parents gave her a
month at a vegan camp as a graduation present from college. While there, she
walked 10 miles a day.
In August 2005,
Tolly had bariatric surgery. She lost 100 pounds, but the weight crept back on.
“It has to be
more than willpower,” she said.
In her case —
and in Baldwin’s — it was. Their binge eating is not what most people call
bingeing, as when they occasionally start on a bag of chips or a gallon of ice
cream and just keep going. Instead, their condition is in the
Diagnostic and Statistical Manual of Mental Disorders. It involves bingeing multiple times a
week. The binges are accompanied by a feeling of being almost in another state
in which they lose all control, quickly consuming large amounts of food. Many,
embarrassed by their behavior, binge in secret. It is common to feel disgust
and shame when the binge ends.
The study that
Baldwin and Tolly participated in is part of a movement to use deep brain
stimulation to treat a variety of disorders that may be caused by problems with
electrical signals in the brain. They include movement disorders and
psychiatric conditions such as depression and obsessive compulsive disorder,
said Dr Edward Chang, a professor of neurosurgery at the
University of California, San Francisco, who was not involved in the binge eating study.
Researchers have
found precise brain circuits, often in areas just about a millimeter in
diameter, that regulate the symptoms of some of these disorders. The
discoveries open the way for studies of deep brain stimulation.
Halpern led the
pilot experiment with Baldwin and Tolly. But first he and his colleagues began
with mice that were prone to obesity. The animals had been fed, but when the
researchers put butter in their cage, they devoured it, eating more than 25
percent of their daily calories in one hour.
The area of
their brains that was activated was the nucleus accumbens, a key hub of the
brain’s reward center, located deep in the center of the brain. In mice,
neurons in the nucleus accumbens became active just before a binge. When the
researchers used deep brain stimulation to calm those neurons, they were able
to prevent the mice from bingeing.
But could it
work in humans?
The group of
scientists began advertising for people who had regained all their weight after
bariatric surgery, believing that it might be due to binge eating disorder.
Baldwin and
Tolly replied. Neither realized they had a binge eating disorder. But binge
eating is “really, really common in individuals who present for weight loss
surgery,” said Lauren Breithaupt, a psychologist at Massachusetts General Hospital
who studies eating disorders.
When Baldwin and
Tolly met with Halpern, both weighed more than they had before weight loss
surgery.
As part of the
study, the researchers provided each woman with a 5,000-calorie feast of their
favorite foods when they were not hungry. The women described the specific
emotional triggers that could set off a binge: for Tolly, thoughts of her
mother, who had recently died; and for Baldwin, thoughts of her work schedule
and responsibilities at home. They agreed to allow the researchers to prompt
them to binge with those triggers as part of the study.
The researchers
recorded electrical impulses in the women’s nucleus accumbens as they ate,
determining that neurons were firing just before the binge and that those
electrical impulses were correlated with the women feeling a loss of control. A
direct brain stimulator might have been able to intercept the signals and
prevent the women from wanting to binge.
After connecting
the devices into the women’s brains, the investigators told Baldwin and Tolly
that they would activate the devices at some time during the next couple of
months but would not tell them when. Both women said they knew immediately when
the devices were activated. Suddenly, they no longer felt insatiable eating urges.
Now their weight
is slowly coming down. Both say that without actively thinking about it, they
are eating differently.
“It’s not
self-control,” Tolly said. “I make better choices.” But she hasn’t begun eating
foods that never appealed to her. “I am not signing up for kale.”
Baldwin said she
noticed a change in her food preferences. She had loved peanut butter and would
find herself eating from the jar with a spoon. Now she doesn’t crave it.
“I would get
these habits like going into a pharmacy to get a prescription, but I might make
a detour to Ben and Jerry’s,” she said.
Once the device
was activated, she said, “I could go into the pharmacy and not even think about
ice cream.”
She also finds
that her tastes have changed. Now her favorite foods are savory instead of
sweet.
“It’s not like I
don’t think about food at all,” Baldwin said. “But I’m no longer a craving
person.”
But does this
show direct brain stimulation can be the answer for people with extreme
bingeing? Breithaupt is cautious.
“It’s just two people,”
she said.
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