The researchers conducted a randomized, controlled trial of 480 college-age women in the San Francisco Bay area and San Diego, Calif., who were identified in preliminary interviews as being at risk for developing an eating disorder. The trial included an eight-week, Internet-based, cognitive-behavioral intervention program called "Student Bodies," which had been shown to be effective in previous small-scale short-term studies. The intervention aimed to reduce the participants' concerns about body weight and shape, enhance body image, promote healthy eating and weight maintenance, and increase knowledge about the risks associated with eating disorders.

The online program included reading and other assignments such as keeping an online body-image journal. Participants also took part in an online discussion group, moderated by clinical psychologists. Participants were interviewed immediately following the end of the online program, and annually for up to three years thereafter to determine their attitudes toward their weight and shape, and measure the onset of any eating disorders

"Eating disorders are complex and particularly difficult to treat. In fact, they have one of the highest mortality rates among all mental disorders," said NIMH Director Thomas Insel, M.D. "This study shows that innovative intervention can work, and offers hope to those trying to overcome these illnesses."

Over the course of a lifetime, about 0.5 to 3.7 percent of girls and women will develop anorexia nervosa, and about 1.1 to 4.2 percent will develop bulimia nervosa. About 0.5 percent of those with anorexia die each year as a result of their illness, making it one of the top psychiatric illnesses that lead to death.

Anorexia generally is characterized by a resistance to maintaining a healthy body weight, an intense fear of gaining weight, and other extreme behaviors that result in severe weight loss. People with anorexia see themselves as overweight even when they are dangerously thin. Bulimia generally is characterized by recurrent episodes of binge eating, followed by self- induced purging behaviors. People with bulimia often have normal weights, but like those with anorexia, they are intensely dissatisfied with their bodies. All eating disorders involve multiple biological, behavioral and social factors that are not well understood.

The intervention appeared to be most successful among overweight women who had elevated body mass indexes (BMIs) of 25 or more at the start of the program. In fact, among these women in the intervention group, none developed an eating disorder after two years, while 11.9 percent of the women with comparable baseline BMIs in the control group did develop an eating disorder during the same time frame. BMI is a reliable indicator of a person?s body fat by measuring his or her weight and height.