It’s all in the head. At least that is what the current research is saying about eating disorders, particularly anorexia. Not that individuals who suffer are products of their own dramatic imaginations. Quite the contrary. A growing body of evidence shows that eating disorders involve brain changes. These may explain why the illnesses are so tough to heal.
I wrote a piece for Scientific American Mind in April/May describing some of the most recent brain studies. I touched on many facets -- from brain regions involved in both anorexia and the effects of the drug ecstasy to abnormalities in the way people with eating disorders respond to pleasant tastes and wins versus losses in a card game.
Most recently, I stumbled across a fascinating study about body-image and eating disorders. Perminder Sachdev, at the University of New South Wales in Sydney, Australia, and colleagues wanted to see if the brains of women with eating disorders processed their body images differently than the norm. The researchers, in essence, peeked under the hood; they imaged the brains of 10 women with anorexia and 10 women without it, while volunteers were looking at digital photos of themselves – compared to photos of other women like them.
When the control women saw pictures of themselves, their brains activated in regions that build up body awareness (namely, the parietal cortex and lateral prefrontal cortex. Also stimulated was a brain region known as the insula, which integrates sensory information (sense of body sense, visual and auditory stimuli) and helps a person represent her body to herself. Finally, the digital photos also turned on the fusiform gyrus, involved in emotional processing.
It seems that women without eating disorders respond to their bodies through a complex mix of visual, sensory and emotional cues. The response differs somewhat, but not that much, to the way the women respond to the bodies of other women.
Women with anorexia showed a whole different picture. In essence, their brains shut down when the women saw photos of themselves. This did not happen when the women saw images of other women with anorexia.
So with anorexia, the brain can function to process body image, just as long as it is someone else’s body.
The study addresses a well-known signature of anorexia: distorted body image. Women with anorexia notoriously think they are fat when emaciated. They also experience intense fear about getting fat. An abnormality with body image and/or emotional processing might just cause a short-circuiting, so that a woman with anorexia’s brain cannot rightly assess his/her real body image. Also, the brain’s feedback mechanism --that is supposed to correct body image misperception-- is thrown out of whack.
It’s provoking to think about why. Women who develop anorexia may born with a processing vulnerability and so develop anorexia. Or as the disease progresses, it may cause the brain shut down either to perpetuate the disease or as a consequence of malnutrition.
The distinction, which is important in terms of treatment, might come with results from studies Sachdev and colleagues plan to do. They want to follow with women with anorexia (and their brain changes) as they go through treatment.
Cross our fingers. More to come.
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