Understanding what processes mediate patients' difficulties in eating

Anorexia nervosa is a rare disorder, but in terms of morbidity and mortality, it is very dangerous. The latest study by Simone Mölbert and her team is trying to understand what processes mediate patients' difficulties in eating. Simone and other scientists are assessing body images in anorexia nervosa using biometric self-avatars in virtual reality. They came to the conclusion that attitudinal components are distorted rather than visual body size estimations.  

1. Why were you interested in this topic? 
When people think about anorexia nervosa, many imagine it is like living with a distorting mirror – that women with anorexia nervosa just don't see how thin they are and therefore their drive for thinness never stops. Interestingly, it is not at all clear whether this is really the case, and if so, why. Some colleagues argue that people with anorexia nervosa just want to illustrate how much they feel too fat, while others see it as a very fundamental perceptual problem. In our study, we tried to disentangle the perceptual aspects from attitudes about bodies, and also investigated how women with anorexia nervosa perceive and evaluate other people that are equally thin as them.   

2. What should the average person take away from your study? 
The most important take home message is that women with anorexia nervosa are well aware of their look. We could not find any difference to healthy women in how well they can identify their weight. However, this does not mean that their problem is trivial. We still found a very clear general preference for severely underweight bodies. In other words, women with anorexia nervosa seem to suffer from incoherent representations of their body. Although they know about their appearance, their underweight and its severity, they still experience it as too fat.   

3. What is the added value of your study/paper for society? 
Anorexia nervosa is a rare disorder, but in terms of morbidity and mortality, it is very dangerous. So far, less than half of the patients fully recover. In order to provide a more effective therapy, it is essential to understand what processes mediate patients' difficulties in eating. On a more general level, our study also contributes to a better understanding of how we represent our body. Our body is always with us and also influences how we see and interact with the world. However, we are only at the beginning of understanding what we represent about our body and how. From our study, we at least learned that isolated representations, like our mirror image, can be completely intact but still interpreted in a disturbed way. This shifts the focus from isolated representations to different representations and their mutual interactions.   

4. Are there any major caveats? What questions still need to be addressed? 
In this study, we needed to focus, but body representation is definitely more than visual perception of the current and ideal body. For example, we also gain information from proprioception and tactile sensation, and it would be very interesting to know more about how these representations interact with visual ones. Also, I would like to know how women with AN conceptually and affectively represent visual percepts. For example, would women with AN label a normal weight person “fat” or would they stigmatize normal weight persons similar to how normal weight persons stigmatize obese persons? For now, body image disturbance in eating disorders remains an enigma.   

5. Is there anything else you would like to add? 
For me, it was an important side-notice that seeing a simulation of weight gain in virtual reality seemed to be extremely interesting for my participants - even though most women with anorexia nervosa were anxious before the experiment! I think that this technology has potential for future developments of therapy, as it might be able to help patients with anorexia nervosa to get used to a higher weight before they actually have it. However, we first need to further narrow down the problem before we can investigate solutions. 


Authors/Co-Authors: 
S. C. Mölbert, A. Thaler, B. J. Mohler, S. Streuber, J. Romero, M. J. Black, S. Zipfel, H.-O. Karnath and K. E. Giel; 


The study was conducted by the Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Max Planck Institute for Biological Cybernetics, Graduate Training Centre of Neuroscience, Tübingen, International Max Planck Research School, University Tübingen, École Polytechnique Fédérale de Lausanne, Brain Mind Institute, Lausanne, Switzerland, Max Planck Institute for Intelligent Systems, Tübingen, Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Germany.