Many women with eating disorders may have a history of childhood anxiety disorders, particularly social phobia and obsessive-compulsive disorder, according to a new study.

The findings, say researchers, suggest that childhood anxiety may signal a vulnerability to the development of anorexia or bulimia.

It has long been noted that eating disorders often co-exist with other psychological problems, including anxiety and Depression.

Some small studies have also suggested that when anxiety disorders arise, they typically precede the onset of anorexia or bulimia.

This latest study is by far the largest to look at the issue, lead author Dr. Walter H. Kaye told AMN Health, and the findings confirm and extend those from previous research.

Better understanding of the role of anxiety could improve the treatment of eating disorders, according to Kaye, a psychiatrist at the University of Pittsburgh Medical Center. It could also aid in getting at the biological roots of eating disorders, as the conditions may share some of their genetic underpinnings with anxiety disorders.

“We’re ultimately looking for genes,” Kaye said, noting that he and his colleagues are recruiting people for an international study aimed at uncovering the genes that contribute to anorexia. The researchers need to find families in which at least two members have had anorexia.

The current study, published in the December issue of the American Journal of Psychiatry, included 672 individuals, nearly all women, who currently or in the past had anorexia, bulimia or both. A group of healthy women the same age was included for comparison. All of the study participants completed standard questionnaires used to gauge their lifetime incidence of various anxiety disorders.

Kaye and his colleagues found that nearly two thirds of the eating disorder patients had ever had an anxiety disorder, occurring in the majority of cases before the onset of the eating disorder.

Of the entire group, 23 percent were diagnosed as having had obsessive-compulsive disorder (OCD) during childhood, before the onset of anorexia or bulimia. Similarly, social phobia arose early on for 13 percent.

OCD is characterized by recurrent, intrusive thoughts and a compulsion to perform certain rituals, such as constant hand washing or repeatedly checking that doors are locked. Social phobia is marked by an intense fear of being embarrassed or judged by others in social situations; children with the disorder may be excessively shy and want to avoid school and activities.

According to Kaye and his colleagues, the high rate of childhood OCD - seen in nearly one quarter of the eating disorder patients, compared with the typical population rate of 2 to 3 percent - was “most striking.”

It’s possible, Kaye said, that the findings could eventually help in identifying children at particular risk of developing anorexia or bulimia.

SOURCE: American Journal of Psychiatry, December 2004.