Washington: A new study has revealed how people suffering from individuals with anorexia nervosa (AN) are able to ignore that bite of tempting foods like chocolate lava cake.
The research by Dr Christina Wierenga, Dr Walter Kaye, and colleagues sheds new light on the brain mechanisms that may contribute to the disturbed eating patterns of anorexia.
They examined reward responding in relation to metabolic state (hungry or satiated) in 23 women recovered from AN and 17 healthy women without eating disorder histories (e.g., the comparison group). Women with active AN weren't studied to reduce potential confounds related to starvation.
The healthy women, when in a state of hunger, showed increased activity in the part of the brain that motivates the seeking of reward, but the women recovered from AN did not. The recovered women also exhibited increased activation of cognitive control circuitry regardless of metabolic state.
Thus, this study found that women who have recovered from anorexia nervosa show two related patterns of changes in brain circuit function that may contribute to their capacity to sustain their avoidance of food.
First, hunger does not increase the engagement of reward and motivation circuits in the brain. This may protect people with anorexia from hunger-related urges. Second, they showed increased activation of executive 'self-control' circuits in the brain, perhaps making them more effective in resisting temptations.
Wierenga, an Associate Professor said that this supported the idea that anorexia nervosa was a neurobiologically-based disorder. The findings suggest that AN individuals, even after recovery, were less sensitive to reward and the motivational drive of hunger.
The study is published in the current issue of Biological Psychiatry.
