Genetic factors account for 56 percent of the risk of developing anorexia nervosa, according to a report in the Archives of General Psychiatry. This information should provide some reassurance to patients and families that the disease is not the result of something they did wrong.

The findings are based on a comparison of anorexia in identical and fraternal twins logged in the Swedish Twin Registry. The study featured 31,406 subjects, born between 1935 and 1958, who were screened for anorexia nervosa and other disorders from 1999 through 2002. Detailed information on all subjects was also provided in 1972 to 1973.

The overall prevalence of anorexia nervosa in women was 1.20 percent and in men, 0.29 percent, lead author Dr. Cynthia M. Bulik, from the University of North Carolina at Chapel, said during a media briefing. She added that during the birth period there was a rise in the anorexia nervosa rate among women, but not men.

As noted, the risk of anorexia was 56-percent related to genetic factors. “The remaining liability was due to environmental factors,” Bulik said.

The presence of a neurotic personality at the 1972-1973 assessment increased the likelihood of later anorexia nervosa by 62 percent, the report indicates. By contrast, low body weight and excessive exercise levels were not predictive of later disease.

“These findings are really good news for patients and really good news for families,” Bulik told Reuters Health. “We have gone through far too much time where parents are blamed for causing this disorder because of how they behave.” Findings from this study and others help eliminate the blame, she added.

The results are also important because they have implications for “targeted prevention efforts” and may “open up new areas of biological intervention,” Bulik emphasized.

SOURCE: Archives of General Psychiatry, March 2006.