Actors pretending to be patients with symptoms of stress and fatigue were five times as likely to walk out of doctors' offices with a prescription when they mentioned seeing an ad for the heavily promoted antidepressant Paxil, according an unusual study being published today.

The study employed an elaborate ruse -- sending actors with fake symptoms into 152 doctors' offices to see whether they would get prescriptions. Most who did not report symptoms of depression were not given medications, but when they asked for Paxil, 55 percent were given prescriptions, and 50 percent received diagnoses of depression.

The study adds fuel to the growing controversy over the estimated $4 billion a year the drug industry spends on such advertising. Many public health advocates have long complained about ads showing happy people whose lives were changed by a drug, and now voices in Congress, the Food and Drug Administration and even the pharmaceutical industry are asking whether things have gone too far.

Nearly every industrialized country bans such advertising, and physicians said the new study raises new questions.

"It is a haphazard approach to health promotion that is driven primarily by the pharmaceutical industry's interest in turning a profit," said Matthew F. Hollon, an internist at the University of Washington in Seattle, who wrote an editorial accompanying the study in today's Journal of the American Medical Association. "The most overlooked problem in the health care system today is the extent to which it is permeated by avarice."

Hollon and the researchers who conducted the study said it was not realistic to expect such marketing to be abolished, given the climate of deregulation in Washington. But they said the ads should be tempered by educational messages funded by a tax on the industry and better training of doctors, or by a moratorium on ads for new drugs until their risks are fully known.

"We can do a much better job with the advertising," agreed W.J. "Billy" Tauzin, president and chief executive of the Pharmaceutical Research and Manufacturers of America (PhRMA). "The ads can do a great job making sure people who need medications and are undertreated get help. We can also make it clear that a particular product is meant for people with this particular problem and for those people only."

The study found that the ads did help patients with a stigmatized illness such as depression get treatment, even as they prompted overmedication of people who did not need treatment. Such marketing in effect exploits the diagnostic gray zone that characterizes many conditions in medicine, including heartburn, arthritis and allergies.

"There is a segment of individuals who would really benefit from pharmacological therapy; there is another large group that won't," said Richard L. Kravitz, lead author of the study and a professor of medicine at the University of California at Davis. "The easiest thing from a marketing standpoint is to increase use in all the categories, and that is what we are seeing."

The researchers sent actors with hidden tape recorders into general physicians' offices in three cities between May 2003 and May 2004. The physicians had previously consented to participate but were not told when they would be tested.

Half the actors simulated patients suffering from depression, describing lengthy periods of sadness, low energy, poor appetite and sleep, and early-morning awakening. The others described having suffered a career upheaval and having fatigue, stress and difficulty sleeping, symptoms that did not warrant medication.

More than half of those without simulated depression who mentioned Paxil got a prescription, underscoring how willing doctors are to go along with patients' requests.