Modern society puts powerful pressure on women to control body weight, penalizing obesity and rewarding thinness in myriad ways. For this reason, some observers say, women suffer from anorexia nervosa -- a disorder in which victims starve themselves, sometimes to death -- at rates 10 times higher than men. Recent studies show, too, that the younger a woman is, the more vulnerable she is to developing anorexia.
Compelling as cultural explanations for the current prevalence of anorexia may be, however, they do not present a complete picture of the disorder and its causes, according to Wade Berrettini, MD, PhD, director of Penn's Center for Neurobiology and Behavior. In a just-published review of studies of anorexic twins, Berrettini found that both members of a pair of identical twin sisters were substantially more likely to suffer from anorexia than were both members of a pair of fraternal twin sisters. Additionally, immediate family members of anorexic women were 10 times more likely to contract the disorder than were members of the general population. Berrettini's review appears in the winter issue of Directions in Psychiatry.
"There's an enormous emphasis on thinness in society's image of female beauty, and most people think a woman's risk of developing anorexia nervosa derives solely from that fact," Berrettini notes. "But studies of twins and families suggest that about half the risk of developing this eating disorder is inherited."
Berrettini is collaborating with Walter Kaye, MD, of the University of
Pittsburgh, whose group has collected blood samples from about 200 families in
which at least two siblings -- not necessarily twins -- have anorexia or
bulimia, a related disorder in which eating binges are followed by self-induced
vomiting. Berrettini's team at Penn is now analyzing the DNA extracted from
those samples to identify the genetic factors underlying a
Contact: Franklin Hoke
University of Pennsylvania School of Medicine