Does eating give you pleasure, or make you anxious?

Perhaps the most puzzling symptom of anorexia nervosa – a disorder that tends to occur in young women – is the refusal to eat, resulting in extreme weight loss. 

While most people have a great deal of difficulty in dieting and losing weight, particularly if a diet extends over many months or years, individuals with anorexia nervosa can literally diet themselves to death.

In fact, this disorder has a very high death rate from starvation.  A new study, now online in the journal International Journal of Eating Disorders, sheds light on why these symptoms occur in anorexia nervosa.
 
Most people find eating to be a pleasant and rewarding experience.  In contrast, people with anorexia nervosa often say that eating makes them more anxious, and food refusal makes them feel better.

Research over the past decade has provided new insights into the brain mechanisms that are associated with the rewarding aspects of eating.  One of these brain chemicals is dopamine, which is released when people or animals eat tasty foods. 

A study led by 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, used a brain imaging technology called positron emission tomography (PET), which permits visualisation of dopamine function in the brain.  

In order to provoke dopamine levels in the brain, scientists administered a one-time dose of the drug amphetamine, which releases dopamine in the brain.