Feb. 27, 2008 -- A study suggesting the widely prescribed antidepressants Prozac, Paxil, and Effexor work no better than placebo for most patients who take them does not present an accurate picture of the research as a whole, a leading depression expert says.
The research analysis included published and previously unpublished data submitted to the FDA by the manufacturers of the three drugs, as well as a fourth, Serzone, which is no longer sold in the U.S.
The researchers concluded that when taken as a whole, the data showed that only a small group of the most severely depressed patients benefited from taking one of the antidepressants.
Antidepressants vs. Placebo
For less severely depressed patients, the antidepressants were found to work no better than placebos, leading the researchers to conclude that most patients who take antidepressants probably shouldn't be on them.
The findings are published in the February issue of the journal PLoS Medicine.
"There seems little reason to prescribe antidepressant medication to any but the most severely depressed patients, unless alternative treatments have failed to provide a benefit," says study researcher Irving Kirsch, PhD, of England's University of Hull.
But in a statement, American Psychiatric Association President-elect Nada Stotland, MD, maintained that studies like those reviewed by Kirsch and colleagues, which compare a single drug to placebo, do not accurately reflect the way doctors prescribe antidepressants.
"We know that many people who are depressed do not respond to the first antidepressant they try," she says. "It can take up to an average of three different antidepressants until we find the one that works for a particular individual. Therefore, testing any single antidepressant on a group of depressed individuals will show that many of them do not improve."
Between 1988 and 2000, prescriptions for antidepressant medications tripled for adults in the U.S., with 118 million prescriptions written in 2005 alone, according to the CDC.
In a statement, GlaxoSmithKline (GSK) representatives express "disappointment" at how the study was being reported by the media, suggesting that news reports may have caused "unnecessary alarm and concern for patients."
"Antidepressant medications remain an important option, in addition to counseling and lifestyle changes, for patients suffering from depression," the statement reads.
The company also addresses the researchers' assertion that the antidepressant makers had selectively published their research data to present their drugs in the best light.
"GSK fully endorses public disclosure of clinical trial results for its medicines and is actively committed to communicating data relevant to patient care," the statement reads. "All the data related to GSK's clinical trial results of [Paxil], regardless of study outcome, are available at the company's clinical trials register at www.gsk.com."
Kirsch repeats the charge in an interview with WebMD.
"The [drug companies] certainly do publish selectively," he says.
"The difference that these medications can make and do make for many patients is not trivial," Angela Sekston, spokeswoman for Prozac-manufacturer Eli Lilly and Company, tells WebMD. "It is very significant, and there is a large body of what I would call prospective data to support that. At the end of the day only a doctor and a patient can determine together which treatment regimen works best."
"Depression is a very serious and chronic evidence that can have fatal consequences," a spokeswoman for Effexor manufacturer Wyeth Pharmaceuticals tells WebMD. "Patients should consult with their doctors to come up with the treatment that is best for them. Antidepressants like Effexor have clearly been shown to be effective."