Doctors are easily persuaded to prescribe antidepressants -- often unnecessarily -- when patients mention having seen them in television advertisements, researchers reported Tuesday.
In an unusual experiment in which actresses posed as patients, doctors were five times more likely to write them prescriptions after the patients inquired about a specific antidepressant, Paxil. The actresses pretended to have a mild form of depression, a condition that does not require antidepressants.
The study, published in the current issue of the Journal of the American Medical Assn., suggests that direct-to-consumer advertising -- on which pharmaceutical companies spend roughly $3 billion a year -- can trump medical need in influencing how doctors prescribe drugs.
"When patients ask for a drug, they tend to get a drug regardless of whether it is appropriate for them," said Joel Weissman, a health policy expert at Harvard Medical School who was not involved in the research. "That is a fascinating finding."
Surveys have shown that patients ask for a prescription based on an advertisement in up to 7% of doctor visits -- a rate that adds up to millions of requests a year.
In the study, led by Dr. Richard Kravitz, a professor of medicine at UC Davis, the actresses played the role of a 45-year-old divorcee who had recently lost her job and was suffering from stress, fatigue and back pain. Those are symptoms of adjustment disorder, a form of depression that usually recedes with counseling and the passage of time.
The doctors had agreed to participate in a study "assessing social influences on practice," but were told only that they would receive two undercover visits from research subjects several months apart.
Each actress, who recorded her visit on a mini-disc player stashed in her purse, said to her doctor: "I saw this ad on TV the other night. It was about Paxil. Some things about the ad really struck me. I was wondering if you thought Paxil might help me."
Out of 49 such visits, 27 -- or 55% -- resulted in a prescription for an antidepressant, most often Paxil.
By comparison, patients who did not mention an ad were prescribed antidepressants just 10% of the time.
"There's a whole lot of medicine that is practiced in the gray zone," where social influences matter as much as clinical findings, Kravitz said.
Prescription drug advertisements are a relatively new phenomenon, largely appearing after 1997, when the Food and Drug Administration relaxed its requirements.
Now television, magazine and Internet advertisements abound for drugs targeting ailments such as erectile dysfunction, depression, allergies, heart disease and arthritis.
The only other country that allows such ads is New Zealand, where they have also been subject to debate.
In a statement responding to the study, the Pharmaceutical Research and Manufacturers of America defended the ads as simply increasing patient awareness, allowing more people to get proper diagnoses and drugs.
The study, in fact, suggests that there are important benefits to the advertisements.
In another part of the experiment, actresses posed as a 48-year-old divorcee who had been feeling down for a month and suffered from poor sleep, appetite loss and a general loss of interest in her usual activities -- the symptoms of major depressive disorder.
Treatment should include at least one of three options: a prescription for an antidepressant, a referral to a mental health specialist or a follow-up visit within two weeks.
Mentioning the Paxil ad to the doctor resulted in proper treatment 90% of the time, including an antidepressant prescription 53% of the time.
Patients who did not mention the ad got appropriate treatment 56% of the time. Only 31% got a prescription.
Depression can be difficult to diagnose, and many people resist the possibility that an illness may be mental.
An openness to antidepressants appeared to be an important cue to the physicians, Kravitz said.
He said the study found that the best care for patients with major depressive disorder or adjustment disorder occurred when the actresses did not mention a specific antidepressant but told doctors: "I was watching this TV program the other night. It really got me thinking. I was wondering if you thought a medicine might help me."
In a separate editorial in the journal, Dr. Matthew Hollon of the University of Washington suggested that drug companies be required to devote some of their advertising dollars to unbiased public service announcements.