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First study finds biological cause of anorexia

Kathleen Blanchard's picture

In a first study, researchers used brain imaging to discover why eating is difficult for those suffering from anorexia.

Researchers explain food intake normally leads to pleasure, but for individuals with the eating disorder, eating stimulates brain responses that cause anxiety and worry.

Walter Kaye, MD, professor of psychiatry and director of the Eating Disorder Treatment and Research Program at the University of California, San Diego School of Medicine and colleagues used PET scans to find different pleasure and reward responses in the brain between healthy women and those with anorexia.

PET scan imaging allowed the researchers to look at dopamine activity, a hormone released in the brain in response to pleasure and reward. For the study, scientists gave study participants a dose of amphetamine that stimulates dopamine.

Eating may stimulate "worry" area of the brain for anorexics

Rather than activating the "pleasure, reward" area of the brain, individuals with anorexia showed increased activity in the area of the brain related to worry and anxiety.

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According to Dr. Kaye, "It’s possible that when people with anorexia nervosa eat, the related release of the neurotransmitter dopamine makes them anxious, rather than experiencing a normal feeling of reward."

He says feeling uncomfortable about food consumption makes it difficult to treat anorexia. The study leads to greater understanding of why it's hard for those suffering from the disorder to eat and gain weight.

An important note is the study participants with eating disorder had recovered from anorexia nervosa. The finding indicates the response seen in the brain was not from being extremely underweight and may be related to pre-existing traits that provoke anxiety from reward and pleasure.

The study leads to greater understanding of why it's so hard for those with anorexia to eat. Unfortunately, the authors note there is no treatment for anorexia nervosa that leads to high death rates from starvation. The finding sheds light on the biological reasons for the eating disorder.

International Journal of Eating Disorders
"Amphetamine induced dopamine release increases anxiety in individuals recovered from anorexia nervosa"
Ursula F. Bailer MD, Rajesh Narendran MD, W. Gordon Frankle MD ,Michael L. Himes BS, Vikas Duvvuri MD, PhD, Chester A. Mathis PhD, Walter H. Kaye MD

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