# Biological Causes of Anorexia Nervosa - Dopamine Connection?



## Dreamer (Aug 9, 2004)

*Brain Differences in Women With Anorexia?
Updated 7/8/2005 10:39:56 PM

By Miranda Hitti*

*WebMd, summary of Biological Psychiatry article, July 8, 2005 -- 
The eating disorder anorexia nervosa may be tied to the brain.*

Researchers recently compared brain imaging of healthy women with 
those who had been anorexic in the past.

*The images showed that the former anorexia patients had 
increased activity in brain areas that make dopamine.

Dopamine is a chemical involved in weight, feeding behaviors, 
reinforcement, and reward.

"This finding might help explain why individuals with anorexia 
nervosa are able to lose weight, resist eating, overexercise, are 
protected from substance abuse, and are insensitive to normal 
rewards," write the researchers.

Their study appears in Biological Psychology's online edition.*

*About Anorexia*

*Anorexia is an eating disorder with both physical and emotional 
traits including:

Severely limited food intake 
Distorted body image 
Refusal to maintain a normal body weight 
Intense fear of gaining weight despite being very underweight

Long-term or severe anorexia can lead to serious health problems. 
It can even be fatal.*

Anorexia's cause is not known. Recovery is possible with proper 
treatment.

Both men and women can have anorexia or other eating disorders. 
Women with anorexia may have infrequent or absent menstrual 
periods. They may not be able to have normal menstrual cycles until 
they regain a healthy weight.

An estimated 0.5% to 3.7% of women have anorexia at some point 
during their lives, states the web site of the National Institute 
of Mental Health (NIMH). The NIMH does not provide numbers for men 
with anorexia.

*Researcher's View*

*"When they are ill, people with anorexia don't seek or respond 
to the kinds of comforts and pleasures most of us enjoy, including 
food," says researcher Walter Kaye, MD, in a news release. 
"They also resist and ignore feedback that signifies their 
precarious state of health," he continues. "They don't see an 
emaciated figure in the mirror. They ignore the most obvious 
warning signs and dismiss comments from loved ones that suggest 
they are seriously and medically ill.

"People with anorexia nervosa have extreme self-denial, not only of 
food, but often of many comforts and pleasures in life, yet [they] 
can be very energetic and productive," Kaye says.

"Taken together, the alterations in the dopamine system may help 
explain the tell-tale symptoms of anorexia."*

Kaye works at the University of Pittsburgh's medical school.

*About the Study*

None of the women had active anorexia. The researchers took that 
approach because malnourishment alters brain chemistry, the news 
release states.

Former anorexia patients had to have been recovered from the eating 
disorder for at least one year prior to the study. They had 
maintained a healthy weight and had regular menstrual periods.

The women also had not taken psychological drugs (such as 
antidepressants) or abused alcohol or drugs for at least three 
months before the study.

*Flip Side of Brain-Obesity Pattern*

*When other researchers scanned the brains of obese people in the 
past, they found the opposite pattern.

Obesity was linked to decreased activity in the brains' dopamine 
reward centers, write Kaye and colleagues.*

The findings support the possibility that dopamine binding might 
be inversely related to weight and eating with anorexia on one end, 
and obesity on the other end of the spectrum.

They call for larger studies on the topic.

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*SOURCES: Frank, G. Biological Psychiatry, online edition, June 
29, 2005. WebMD Medical Reference from Healthwise: "Anorexia 
Nervosa: Topic Overview." National Institute of Mental Health: 
"Eating Disorders: Facts About Eating Disorders and the Search for 
Solutions." News release, University of Pittsburgh Medical 
Center.*

Updated 7/8/2005 10:39:56 PM


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