Anxiety disorders in childhood may be a prelude to eating disorders that often strike young women in their teens and 20s, according to a new study.

Researchers at the University of Pittsburgh found that two thirds of people with eating disorders had experienced some sort of clinical anxiety, such as social phobia, panic attacks or obsessive compulsive disorder, at some point in their lives.

A significant number of them — 42 percent — developed an anxiety disorder when they were children, long before their eating disorders appeared. After they had recovered from an eating disorder, anxiety remained more common among the women than in the general population. Twenty percent to 30 percent typically experience anxiety over the course of a lifetime.

"We identified a strong link between anxiety disorders and eating disorders that shows they not only share many of the same personality traits, but also likely share a genetic pathway," said Dr. Walter Kaye, a professor of psychiatry at Pittsburgh's School of Medicine and lead author of the study published in the December issue of the American Journal of Psychiatry.

The study, carried out by an international team of researchers, included 672 individuals with the eating disorders anorexia nervosa — unable to eat — or bulimia nervosa — food binging and purging.

The strength of the bond between anxiety and eating disorders was further bolstered by a finding that nearly all the women reported having certain anxiety traits, such as harm avoidance, generalized anxiety and perfectionism, even if they don't have symptoms severe enough to be diagnosed as an illness.

The researchers used standard psychiatric tests to assess anxiety, and found that two anxiety disorders appeared more often than others — 41 percent of the participants had a history of obsessive compulsive disorder, which involves distressing obsessions and senseless rituals — and 20 percent had social phobia.

Particularly striking was that 23 percent of the patients reported having had obsessive compulsive disorder in childhood — normally the condition begins in the 20s, with only 2 percent to 3 percent of cases occurring in children. Kaye said the condition could be a particularly important signal that those children need to be watched for eating disorders down the road.

The same collaborative group is currently conducting a study on the genetic contribution to anorexia, seeking a study group made up of families that have at least two relatives with the condition.