Teens with anorexia nervosa have bigger brains than those without the eating disorder, a finding that suggests biology may play a larger role in the condition than realized.
Specifically, the teenage girls with anorexia had a larger insula, a part of the brain that is active when you taste food, and a larger orbitofrontal cortex, the part of the brain that tells you when to stop eating, said researchers from the University of Colorado School of Medicine.
"While eating disorders are often triggered by the environment, there are most likely biological mechanisms that have to come together for an individual to develop an eating disorder such as anorexia nervosa," Dr. Guido Frank, an assistant professor of psychiatry and neuroscience, said in a university news release.
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Anorexia causes people to lose more weight than is considered healthy. Larger volume in the orbitofrontal cortex could be a trait that causes these people to stop before they've eaten enough, the study suggests. And the right insula, which integrates body perception, might contribute to the sense of being fat despite being underweight.
The small study included 19 teen girls with anorexia and 22 teen girls without the disorder who underwent MRI brain scans. The findings were published recently in the Journal of the American Academy of Child and Adolescent Psychiatry.
Frank said similar results in children with anorexia nervosa and in adults who had recovered from the disease raise the possibility that insula and orbitofrontal cortex brain size could increase a person's risk of developing an eating disorder. This study did not, however, prove a cause-and-effect relationship between the two.