People with anorexia have abnormalities in the ‘comprehension’ areas of the brain.

Anorexia nervosa is an eating disorder that is characterized by low body weight, fear of weight gain, strong desire to be thin, and excessive food restriction. There is much overlap between different eating disorders but anorexia is different than the others because the affected individuals are usually underweight. Anorexia affects 0.9% of women at some point in their life but it can also affect men, 0.3% of them in their life time. There are many possible causes of anorexia including: genetic susceptibility, gastrointestinal disease, low self-esteem, depression, anxiety, and perceived body ideals in popular culture. Anorexia is more than just a problem of not eating, many people with anorexia lack the ability to comprehend their own body image. They may think they are overweight when they are not, or they may not be able to understand that they are dangerously thin even when their loved ones tell them so. In this regard, people with anorexia are said to lack self insight. A group of researchers investigated whether this lack of self insight or comprehension was tied to differences in brain structure. The findings, published in the journal of Psychological Medicine found that people who suffer from anorexia have structural defects in the brain regions associated with self insight that are not found in people without anorexia.

The team recruited 24 patients with anorexia but who had recently returned to a healthy weight and compared them to 29 patients with body dysmorphic disorder (obsessive thoughts about some aspect of your appearance) and 31 healthy patients. Each of the subjects was put into an MRI to measure the connectivity of their brain and asked a series of questions about their ability to form self insight. The researchers found that subjects with anorexia who scored the lowest on the self insight test had the most abnormalities in brain regions that are linked to habit/ritual formation, error detection, conflict monitoring, and in reward and decision making. This could mean that people suffering from anorexia have a hard time comprehending that what they are doing is harmful to their body. The researchers were also able to show that the abnormal regions of the brain from people with anorexia had longer path lengths and that these longer path lengths were associated with worse scores on self insight tests. Path length can be thought of as the distance between two neurons (brain cells). Normally you want this distance to be short so that they can communicate quickly. The longer this path length, the longer it takes for the signal from one cells to reach the next cell. This could effectively short out the signal or make it unclear.

This research shows that anorexia is more than just a problem of not eating. People with anorexia may lack the self-judgment that tells them ‘starvation is bad’ or ‘you are too thin’. Additionally, people with anorexia may not be able to resolve internal conflicts. If they think “I’m way too thin even though I think I am fat” their brain may not be able to determine which of the two statements is true. As more evidence mounts for neurological defects in eating disorders hopefully the way we treat them also changes. Even if a person with anorexia gains back all their weight, it is a slippery slope and they may easily fall back into the cycle of starvation and lack of insight. Treating anorexia properly may require us to help them understand the difference between perception and reality and guide them through that internal conflict resolution.


Photo Credit: Flickr daniellehelm


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