• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Download full size image

New Study Questions Effectiveness Of Antidepressant Drugs

Posted on: Friday, 18 January 2008, 08:40 CST

A report issued today in the New England Journal of Medicine (NEJM) found antidepressant drugs are not as effective as published reports indicate because unfavorable trial outcomes were excluded or underreported in published test results.

The report examined previous studies on twelve antidepressants, including many of the best-selling drugs, and determined the published results of those studies were overstated because the majority of trials with negative outcomes were never published.

Erick Turner and his team at Oregon Health & Science University conducted the research.

After examining data from both published literature and from FDA documents that pharmaceutical companies use to record details of their drug trials, Turner and his team found significant discrepancies between the two sources.

Of the 74 studies that started for 12 different antidepressants, only 38 produced positive results for the drug under test. Of these, 37 were published. However, of the 36 tests with negative outcomes, only 3 were published.

Additionally, there were 11 tests researchers interpreted as negative but were nonetheless reported with favorable outcomes . Even if not deliberate, researchers said this kind of reporting could be bad news for patients.

“Not only were positive results more likely to be published, but studies that were not positive, in our opinion, were often published in a way that conveyed a positive outcome,” said the report, according to a Reuters article.

“Selective publication can lead doctors to make inappropriate prescribing decisions that may not be in the best interest of their patients and, thus, the public health,” the authors said.

In the case of Paxil, made by GlaxoSmithKline (GSK), five out of seven negative studies were not published. In the case of Wellbutrin SR, also made by GSK, researcher found three studies completed, but the two that were negative were never published.

Similar results were found for Zoloft, made by Pfizer, in which five studies were completed but the three that showed the drug ineffective were never published. A fourth study ruled questionable by the FDA was written and published as though the drug had worked.

Representatives for pharmaceutical companies mentioned in the report have affirmed their companies’ commitment to full disclosure of clinical trial results for their antidepressant drugs.

A Glaxo spokeswoman said in a Reuters interview that the company posts all its data from all trials, both positive and negative, on the Internet. “GlaxoSmithKline agrees that public disclosure of clinical trial results for marketed medicines is essential and fully supports registration of all trials in progress,” she said.

In an email communication with Reuters, Pfizer spokesman Jack Coz said, “Pfizer is committed to the communication of results of all registered clinical studies, regardless of outcome. More specifically, we have committed to disclose clinical trial results within one year after study completion for all of our marketed products.”

Dr. Turner and his team did not determine the source of blame for the unpublished studies. He suggested medical journals might have played a role by deciding to publish only favorable results.

“There’s an expectation that if you get a positive result, that’s what you’re supposed to do, and if you get a negative result you have failed,” said Mr. Turner. “The first impulse is to say, ‘I was wrong. Maybe I should move on to something more interesting’” so the results may never get published.

Shares of antidepressant drug makers fell Thursday after the NEJM report was released.

---

On the Net:

New England Journal of Medicine

Oregon Health & Science University

Source: redOrbit Staff

More News in this Category