Brains of anorexia patients may not fully recover after treatment, study says

March 1 (UPI) -- A new study at the University of Colorado Anschutz Medical Campus found the brains of adolescent anorexia nervosa patients are not fully recovered after treatment and weight gain.

Researchers followed 21 female adolescents before and after treatment for anorexia and found their brains had an elevated reward system even after treatment compared to 21 participants without an eating disorder.

"That means they are not cured," Dr. Guido Frank, an associate professor of psychiatry and neuroscience at the University of Colorado School of Medicine, said in a press release. "This disease fundamentally changes the brain response to stimuli in our environment. The brain has to normalize and that takes time."

For people with anorexia nervosa, central reward circuits in the brain that govern appetite and food intake operate improperly. Researchers found the reward system was elevated when patients were underweight, and remained elevated even after normal weight was restored.

The neurotransmitter dopamine mediates reward learning and is thought to play a vital role in the pathology of anorexia nervosa, with animal studies appearing to confirm the theory, the researchers said.

In order to prove this theory, the researchers conducted a series of reward-learning taste tests on 42 female participants, 21 with anorexia nervosa and 21 with a healthy weight, while undergoing MRI scans of their brains.

The research showed reward responses were higher in adolescents with anorexia nervosa than in participants without the disease. The study also showed that participants with anorexia had widespread changes to parts of the brain, such as the insula, which processes taste along with other functions -- including body self-awareness.

The results showed the more severely altered a patient's brain is, the more difficult it is to treat the condition.

"Anorexia nervosa is hard to treat," Frank said. "It is the third most common chronic illness among teenage girls with a mortality rate 12 times higher than the death rate for all causes of death for females 15 to 24 years old. But with studies like this we are learning more and more about what is actually happening in the brain. And if we understand the system, we can develop better strategies to treat the disease."

The study was published in the American Journal of Psychiatry.