There is now conclusive evidence that teens that have anorexia nervosa also have bigger brains than teens that do not suffer with the disease. Scientists have found that specific areas of the brain – the insula and the orbitofrontal cortex – are larger in anorexics. The insula is the region of the brain that activates when food is tasted and it is also responsible for integrating a person’s body image. This function could possibly contribute to a person’s false perception of being overweight despite the reality of being underweight. The orbitofrontal cortex is responsible for signaling satiety and telling a person when to stop eating. Researchers now believe that the larger-than-average brain volume in these key regions of the brain is the reason that some individuals are able to successfully starve themselves.
Current statistics report that approximately eight million Americans suffer from eating disorders and about one out of every 200 woman is anorexic. Experts agree that anorexia and other eating disorders are oftentimes triggered by environmental factors. But the findings of the recent studies show that there is a possible biological component to the disease, as well. Thus far, no definitive cause-and-effect relationship between brain size and anorexia has been established. But researchers are studying the possibility that brain size may, in fact, predispose some people to anorexia and other eating disorders.
Friederich HC, Walther S, Bendszus M, et al. Grey matter abnormalities within cortico-limbic-striatal circuits in acute and weight-restored anorexia nervosa patients. NeuroImage. 2012;59:1106–1113
Kaye WH, Wagner A, Fudge JL, Paulus M. Neurocircuitry of eating disorders. Curr Topics Behav Neurosci. 2011;6:37–57