(The New York Times News Service) -- When a teenage girl develops anorexia, a team of experts usually takes charge of bringing her back to a normal weight, while her parents stand on the sidelines.

But a promising and controversial new therapy gives parents the primary responsibility for an anorexic child's recovery.

The goal of the therapy is to mobilize the family as a whole in a fight against the eating disorder, said Dr. James Lock, an associate professor of psychiatry at Stanford School of Medicine and the lead author of an extensive treatment manual for the technique, published last year by Guilford Press.

The parents are told that no one knows what causes anorexia - a problem that affects boys but is far more common in girls - and that the illness is no one's fault.

They are encouraged to think of the disorder as an outside force that has taken over their daughter's life.

And they are exhorted to be unwavering in finding ways to feed their child.

The message, Lock said, "is that food is medicine and medicine must be delivered."

The technique, developed at the Maudsley Hospital in London, is now being tested in the United States.

Preliminary studies suggest it is strikingly effective in helping many adolescents to recover from anorexia, an illness that carries the highest mortality rate of any psychiatric condition and is notoriously difficult to treat.

But it is not without critics.

Traditional theory holds that the self-starvation of anorexia represents an adolescent's desperate attempt to assert independence in the face of overbearing or intrusive parents. Some therapists worry that the Maudsley approach will exacerbate a teenager's feelings of helplessness - and make the illness worse.

Other experts argue that the method may be impractical in many families where two parents work.

Lock and other experts who use it agree that the therapy is not suited to every family, and that it is impossible to use in a minority of families, those with parents who are abusive or have other major psychiatric problems.

But the experts say that in many cases, the parents are in the best position to help an adolescent get better, especially in a world of managed care, where hospital stays are short and therapy sessions are limited.

The principles underlying the approach, Lock said, are similar to those used in residential eating disorder programs.

In those programs, Lock said, "One of the first things you notice is that the children, when you take the responsibility for food and eating away from them, can actually eat. They're not torn and conflicted and they usually can gain weight."

And once a safe weight is restored, he and other experts contend, the child can move, unencumbered, to the second part of the therapy, when the focus is on gradually shifting the responsibility for eating back to the child.

Dr. Katharine L. Loeb, a research scientist at the New York State Psychiatric Institute in Manhattan who is directing a pilot study of the therapy, said many parents expressed perplexity about ways to induce a resistant teenager to eat.

"I tell them: "The same way you got her to take a distasteful medicine when she was younger. It wasn't a matter of taking the antibiotic or not, but of how it was going to happen,"' she said.

Loeb said the parents might say to their daughter, "Don't think that it's an option not to eat because we are not going to let you starve."

In some cases, they may tell an adolescent she cannot leave the table until she has eaten a certain amount. Or they may emphasize the rewards that come with weight gain - and the gains in health and physical strength that accompany it.

For example, Elizabeth H., a 15-year-old from Westchester County who participated in the study, said it was the promise of a bicycle trip to Cape Cod - a trip she would be physically capable of only at a higher weight - that made the difference.

"All I could think of was a tunnel vision of my trip," she said. "So I gained 20 pounds in two months."

Whatever approach the parents adopt, they must be "at the same place on the same page" in their efforts, Loeb and other experts said. The therapist monitors the process, offering suggestions and making sure parents do not use the treatment as an excuse to indulge in emotional tyranny.

"This is not a green light for parents to be aggressive, controlling or hostile" toward their children, said Dr. Daniel le Grange, director of the eating disorders program at the University of Chicago and an author of the treatment manual.

In adolescents, Loeb noted, anorexia can develop so insidiously that parents sometimes do not realize that something is wrong until their child becomes drastically underweight.

Making detection more difficult, many normal teenage girls diet or indulge in odd eating habits. And adolescence is a time of changing bodies, rapid spurts of growth - and baggy clothing.

"All the kids were shooting up and getting thinner," said Elizabeth H.'s mother. "If you looked at her in clothes, you really couldn't tell."

Teenagers with anorexia, many experts said, often become young tyrants, demanding that parents provide minuscule portions or buy only fat-free foods, taking hours to finish a meal or lying about how much they have eaten during the day.

But bargaining, Lock said, only plays into the illness.

"With anorexia, you never win, you always lose," he said. "If you start with broccoli, soon it's going to be half a serving of broccoli."

Copyright 2002 The New York Times News Service. All rights reserved.