By BENEDICT CAREYOne of the most widely used treatments for the eating disorder anorexia nervosa, the antidepressant Prozac, works no better than dummy pills in preventing recurrence in young women who have recovered from it, researchers are reporting today.The study, the most rigorous to date to test the use of medication for anorexia, should alter treatment for an illness that is often devastatingly chronic and that has a higher mortality than any other psychiatric disorder, experts said. Fewer than a third of the study's participants, who also received regular psychotherapy, remained healthy for a year or more, whether they received drug treatment or not, the study found. An estimated 1 percent of Americans, or about three million people, mostly young women, will at some point suffer from the self-starvation and obsessive anxiety about weight that characterize anorexia, and surveys find that about two-thirds of them receive treatment with Prozac or similar antidepressants, which are considered generally interchangeable. Research suggests that the drugs can be useful in helping people recover from bulimia nervosa, an eating disorder involving bingeing and purging that causes less dramatic weight loss than anorexia. But the new findings put to rest hopes from earlier work that these benefits might carry over to anorexia, experts said."Physicians who are trying to help people with anorexia remain symptom-free should not count on getting substantial benefits from antidepressants," said Dr. B. Timothy Walsh, the lead author of the study, who is director of eating disorders research at the New York State Psychiatric Institute at the Columbia University Medical Center."Doctors should be looking at other things, like good psychological treatments," Dr. Walsh said.In the study, appearing in The Journal of the American Medical Association, researchers from Columbia and the University of Toronto monitored 93 women, ages 16 to 45, who, after receiving intensive psychotherapy, gained enough weight to fall into the normal range. Half the group then received daily doses of Prozac, and the other half took dummy pills. All of them continued in weekly psychotherapy, where they practiced techniques to examine and diffuse irrational assumptions about weight and body image. After a year, 26 percent of those on Prozac and 31 percent of those taking placebo pills remained in a healthy weight range, the study found. The differences between the two groups, in weight and on measures of beliefs about food and weight gain, were not large enough to be significant."This study will change practice, beginning with the community of doctors who specialize in eating disorders and spreading more broadly" to other doctors, said Dr. Scott Crow, a psychiatrist at the University of Minnesota, who wrote an editorial accompanying the study. Dr. Walter Kaye, a professor of psychiatry at the University of Pittsburgh, said the new findings should not rule out the use of antidepressant treatment altogether. In 2001, Dr. Kaye published a small study suggesting that Prozac did help some young women who had recovered from anorexia keep on weight. They were women who did not binge — they ate very little — and did not receive psychotherapy. "For patients like these, who don't have access to psychological treatments, who have a choice between medication or nothing at all, I think the medication could help," Dr. Kaye said. All agree that the new findings emphasize the importance of thinking creatively about treatment. The best psychotherapy available, said Dr. Crow, helps only about a third of anorexia patients recover. Another third learn to moderate and live with their aversions to food, while the rest develop a chronic disorder, putting them at high risk for suicide or death from starvation.Researchers are experimenting with several new therapeutic techniques. One is a type of family therapy for adolescents, in which parents take charge of all meals. The parents decide how much their daughter or son should eat — based on specific guidelines — and reward good behavior, if appropriate. Several studies suggest that this approach can lead to sustained recovery in some teenagers. Some evidence suggests that this kind of close monitoring by a therapist can also help adults with the disorder. Psychiatrists have experimented, so far in vain, with a wide variety of drugs for treatment, including antipsychotic medications, so-called mood-stabilizing drugs like lithium and agents similar to the active ingredients in marijuana. "It's disappointing, really," Dr. Walsh said. "We would like to do better. We need to do better."