People With Anorexia Aren’t Motivated By Hunger Signals
The brains of women who have recovered from anorexia nervosa react differently to hunger signals than the brains of women who have never suffered from an eating disorder, according to new research from the University of California, San Diego.
Hunger normally provides people with a strong motivation to eat, but people with anorexia are able to resist hunger signals and continually starve themselves. This new research provides possible insight into how those with anorexia are able to resist hunger for such a sustained period of time.
For this study, the UCSD researchers analyzed the reward responses of 40 women, 17 of whom had never suffered from an eating disorder and 23 of whom had recovered from anorexia nervosa. Using monetary rewards for stimulation, the study analyzed the brain regions that govern the processing of immediate rewards and decision-making regarding future rewards. The researchers specifically looked for differences between the way the brain processed rewards when the individual was hungry and the way it processed rewards when the individual was satisfied.
Reward Processing in People With Anorexia
The results of the study showed that hunger significantly affected both the immediate reward processing and the long-term reward-based decision making of people who had never lived with disordered eating. Hunger caused the areas of the brain responsible for immediate processing to become more active and the areas involved in long-term decision making to become less active.
However, the researchers did not find this to be the case for the 23 subjects who had recovered from anorexia. In these individuals, there was no change in either their short-term reward responses or future reward planning when they were experiencing hunger compared to their responses when satisfied. Furthermore, this group showed stronger overall activation in the cognitive control areas of the brain that play a major role in making decisions about future rewards.
People With a History of Anorexia May Have Greater Self-Control
This suggests that brain function contributes to anorexia in two important ways. First, hunger signals do not motivate people with anorexia to eat as they do in healthy people. Second, people with anorexia may have greater self-control that enables them to stay focused on their goal of losing as much weight as possible despite hunger signals and other motivations to eat.
Anorexia nervosa is characterized by an intense fear of gaining weight accompanied by extreme weight loss. People who suffer from this disorder also have a distorted image of their own bodies, which helps to fuel their unreasonable fear of weight gain. The reasons people with anorexia starve themselves are well understood, but this new study provides new insight into how those with anorexia are able to continually starve themselves and ignore the motivations that normally drive people to eat.
To conduct this study, the UCSD researchers chose to use monetary rewards as stimulation rather than food rewards, because people who have recovered from disordered eating often have continued anxieties surrounding food that could have affected the results.
The researchers hope that the data from this study will help with the development of new treatment approaches for anorexia and other eating disorders at the UC San Diego Eating Disorders Treatment and Research Program.
The results of the study were published in the journal Biological Psychiatry.