The Brain’s Response To Rewards Is Different In People With Anorexia
New research from the University of California, San Diego School of Medicine may explain how individuals with anorexia nervosa can continuously starve themselves, even after becoming emaciated.
“When most people are hungry, they are motivated to eat,” said Christina E. Wierenga, PhD, the study’s first author and UC San Diego associate professor of psychiatry. “Yet individuals with anorexia can be hungry and still restrict their food intake. We wanted to identify brain mechanisms that may contribute to their ability to ignore rewards, like food.”
The researchers believe the findings add to the wealth of evidence indicating the role of brain mechanisms in eating disorders and could potentially allow for more effective and targeted treatments.
According to the findings, published in Biological Psychiatry, the findings showed differences in how the brains of women who have recovered from anorexia responded to rewards.
“They showed decreased response to reward, even when hungry. This is opposite of healthy women without an eating disorder, who showed greater sensitivity to rewards when hungry,” explained Wierenga.
Walter H. Kaye, MD, a professor of psychiatry and director of the Eating Disorders Treatment and Research Program at UC San Diego and senior author, said the study’s results further support the view that neurobiology contributes to this disorder. “Our study suggests that brain circuitry differences in anorexics make them less sensitive to reward and the motivational drive of hunger. Put another way, hunger does not motivate them to eat.”
For the study, the team evaluated brain function in 23 women who had already recovered from anorexia, along with 17 healthy women who have no record of eating disorders. The group of women who had recovered from anorexia included women who were normal weight, rather than those in an active phase of the disorder to avoid the risk of malnutrition influencing the findings. The researchers analyzed brain circuitry associated with motivation and reward during two distinct metabolic periods: when they are hungry and again when hunger is satiated.
According to the findings, participants also showed significantly greater activity in regions of the brain essential for self-control among the recovered anorexic group regardless of metabolic state, along with the differences observed in brain response to reward. The researchers suggest this indicates these individuals potentially have a higher level of self-control than people without eating disorders.
“We are using these new insights about brain mechanisms that contribute to disordered eating to guide the development of new treatment approaches in our Eating Disorders program at UC San Diego,” Kaye said. “We’re very motivated to help advance efforts to better understand and address this life-threatening disorder.”