Anorexic women have different brain circuitry
By Margaret Rogers
Eating disorders can affect different people in different but have you ever wondered why one person 
may develop anorexia whilst another may become obese?
A recent study was conducted by a researcher from the University of Colorado School of Medicine which shows that, in anorexic women, the reward circuits of the brain are sensitised whilst in obese women they are desensitised. The study findings further suggest that all eating behaviours are related to brain dopamine pathways which are associated with addiction.
Functional magnetic resonance imaging (fMRI) was used by Guido Frank MD and a team of his colleagues to look at brain activity in 63 female participants. All participants were either anorexic or obese. The images were compared to women who were considered to be of ‘normal’ weight.
A test which has been associated with brain dopamine function in the past was used by the researchers. All of the participants were visually conditioned to associate certain shapes with either sweet or non-sweet solutions. They then received the taste solutions as they expected or unexpectedly.
During the fMRI sessions, the researchers found that an unexpected sweet-tasting solution resulted in increased neural activation of reward systems in anorexic patients and decreased activation in obese patients. Previous study has shown that, in rodents, food restriction and weight loss have been associated with greater dopamine-related reward responses in the brain.
Dr Frank said ‘It is clear that in humans the brain’s reward system helps to regulate food intake. The specific role of these networks in eating disorders such as anorexia nervosa and, conversely, obesity, remains unclear.
The study was published in Neuropsychopharmacology. Scientists agree that more research in this area is necessary.
