Brains of women with bulimia respond differently to women without bulimia when shown images of slim women. Both groups responded similarly to pictures of food, according to a study published in the open access journal BMC Psychiatry. The work suggests that treatments for bulimia should have a strong focus on self image rather than solely or primarily on issues with food.

The neurological process behind bulimia that brings about binge-eating food and purging is poorly understood. In an attempt to increase knowledge about this type of behaviour researchers from King's College London Institute of Psychiatry investigated the brain patterns in a group of 21 women with bulimia and 23 women without. They found that brain responses between the two groups only differed when they were shown pictures of slim women.

To investigate the difference in brain patterns the women underwent functional MRI scans. While these scans were being performed the women were shown images that included appetising food, slim women, control images and also a black cross, which provided a baseline signal. Before being shown these images the study's participants were given instructions such as "imagine eating this food" and "compare your own body against the bodies in the pictures".

When comparing these brain scans, it was found that the part of the brain concerned with self-reflection was activated more in women with bulimia when shown images of slim women than it was in healthy women. In contrast, when shown images of food there were no marked differences between both groups of women. Both images of thin women and food pictures resulted in an increase of subjective anxiety in women with bulimia; this was measured during the scanning procedure.

Frederique Van den Eynde, currently at McGill University and the Douglas Mental Health Institute in Montreal, lead author of the study, says "This supports the idea that psychotherapy for bulimia nervosa should have a particular focus on body image and not solely focus on food and eating related issues."

The researchers think their results could also be used further develop other clinical treatments that may counteract the brain activation patterns found in the current study.