The study explains how brain mechanisms contribute to the disturbed eating patterns of anorexia.
“Hunger is a motivating drive and makes rewards more enticing,” said Christina Wierenga, associate professor of psychiatry at University of California, San Diego. “We have long been puzzled by the fact that individuals with anorexia nervosa (AN) can restrict food even when starved.”
Researchers examined the responses to rewards in relation to metabolic state, either hungry or satiated, of 23 women who recovered from the condition and 17 healthy women who did not have any eating disorder history.
Healthy women, when hungry, showed increased activity in the part of the brain associated with seeking the reward, while women who recovered from anorexia did not show the same activity patterns.
Participants who have recovered from anorexia displayed two related patterns of changes in the brain circuits that contribute to their ability to sustain their distancing from food.
The first pattern showed that hunger does not increase the stimulus to the reward and motivation circuits in the brain. This explains why people with anorexia are protected from hunger-related urges.
The second pattern showed an increased activation of the executive “self-control” circuits in the brain, giving these women a more effective ability to resist temptations.
‘This study supports the idea that anorexia nervosa is a neurobiologically-based disorder,’ Wierenga noted.
The study published in the journal Biological Psychiatry.