Some Forms Of Anorexia Nervosa May Be Associated With Lasting Neurological Effects, Even After Recovery
Researchers find that anorexia is associated with altered levels and patterns of serotonin activity in the brain
PITTSBURGH, September 9, 2005 — University of Pittsburgh School of Medicine investigators have discovered that a distinctive type of anorexia nervosa is linked to altered brain serotonin function. Their findings were published in the Sept. 5 edition of the Archives of General Psychiatry.
"These data offer the promise of a new understanding of the cause of anorexia nervosa and new drug and psychological treatment targets," said the first author of the study, Ursula Bailer, Ph.D., associate professor of psychiatry at the Medical University of Vienna, Austria. Dr. Bailer was at the University of Pittsburgh when the study was conducted.
Anorexia nervosa is a serious eating disorder that tends to strike younger women, but also can affect males. It is characterized by the relentless pursuit of thinness and obsessive fears of being fat. Self-starvation, extreme weight loss and related medical complications that accompany anorexia nervosa can result in death, giving it the highest mortality rate of any psychiatric disorder. Unfortunately, there are no proven treatments.
Research has demonstrated that there are two main anorexia subtypes, a group in whom patients restrict their eating (restricting-type anorexia) and a group that alternates restrictive eating with bulimic behaviors such as purging and/or binge eating (bulimia-type anorexia). Previous evidence has suggested that alterations in the activity of serotonin, a brain chemical involved in communication between nerve cells, may contribute to the appetite alteration in anorexia nervosa and play a role in anxious, obsessional behaviors and extremes of impulse control.
Using a type of imaging called positron emission tomography, or PET, the Pittsburgh team, which included investigators at the National Institutes of Health and the University of California, San Diego, compared serotonin activity in 25 women who had recovered from either sub-type of the disorder with that in women who had never developed an eating disorder. The PET scans showed higher serotonin receptor activity in several parts of the brains of women who had recovered from the bulimia-type anorexia. Serotonin receptor activity was also somewhat heightened in the group who had recovered from restricting-type anorexia, but the difference was not statistically significant. On the other hand, the women with previous restricting-type anorexia who showed the most signs of anxiety—according to a measure of “harm avoidance”—also had the highest levels of serotonin receptor activity.
According to Walter Kaye, M.D., professor of psychiatry at the University of Pittsburgh School of Medicine and head of the international group of clinicians, researchers and statisticians attempting to understand the causes of eating disorders, this latter finding is particularly significant because a high level of harm avoidance is believed to make some people especially vulnerable to developing anorexia nervosa. “Studies suggest that harm avoidance is present in many young people before they develop anorexia. And, our work suggests that persistent alterations of serotonin levels may lead to increased harm avoidance and anxiety, which may trigger anorexia,” explained Dr. Kaye.
Although they cannot say for sure how harm avoidance is related to altered brain serotonin activity or how it might trigger anorexia, the researchers note that one of the regions of the brain with altered serotonin activity in the formerly anorexic women has extensive connections to other regions of the brain that play a pivotal role in controlling anxiety and fear. Based on this knowledge, in the near future it may be possible to target drugs or psychological approaches that affect these areas of the brain.
“Every new finding in this field brings us closer to identifying new approaches for treatment and diagnosis of these serious conditions. We are very grateful for the research that Dr. Kaye and his colleagues are doing and encourage increased funding for continuing this very important work,” said Lynn Grefe, chief executive officer of the National Association of Eating Disorders, a nonprofit organization dedicated to expanding public understanding of eating disorders and promoting access to quality treatment for those affected through education, advocacy and research.
In addition to Drs. Bailor and Kaye, other authors on the study include Julie C. Price, Ph.D., Carolyn C. Meltzer, Ph.D., Lisa Weissfield, Ph.D., Chester A. Mathis, Ph.D., Angela Wagner, M.D., Jessica Hoge, Shannon E. Henry, Scott K. Ziolko and Claire W. McConaha, of the University of Pittsburgh; Wayne C. Drevets, M.D., of the National Institutes of Health; and Guido K. Frank, M.D., of the University of California, San Diego.
This study was supported by grants from the National Institute of Mental Health, the Price Foundation, of Geneva, Switzerland, and through an Erwin-Schrödinger Fellowship of the Austrian Science Fund.