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Depression drugs — a cautionary tale

Posted by medconsumers on June 16, 2010

Have you noticed the recent spate of articles about antidepressants like Prozac, Zoloft, and Paxil… and how they are little more than placebos? These were the superstar drugs of the 90s. Once they were featured on the covers of Time and Newsweek. Now both magazines have joined the media chorus, telling us that these drugs are helpful only to people with severe depression (but even this claim is challenged).

It’s not news, really. I wrote about a meta-analysis of 22 Prozac vs placebo studies, which came to exactly the same conclusion in 1992 (click here). I don’t recall that this analysis got any media attention at the time…perhaps because it appeared in a relatively obscure medical journal (Journal of Consulting and Clinical Psychology). From then on, I wrote infrequently about Prozac’s minimal efficacy. Depression is such a terrible disorder that no one wanted to hear that Prozac and its multiple knock-offs weren’t all they cracked up to be. Besides, every third person I knew seemed to be on one of these antidepressants and people were hopeful. Depression had come out of the closet and was finally taken seriously.

In the intervening years, an investigative reporter took an in-depth critical look at the drug company-sponsored trials that won FDA approval for antidepressants. In 2002, the Washington Post published an article by Shankar Vedantam, who concluded, “After thousands of studies, hundreds of millions of prescriptions and tens of billions of dollars in sales, two things are certain about pills that treat depression: Antidepressants like Prozac, Paxil and Zoloft work. And so do sugar pills.”

Vedantam’s statement was based on unpublished as well as published studies. It was the extent of the hidden evidence—the unpublished studies—that was most revealing. To get FDA approval for its new antidepressant, a drug company need only present the FDA with two studies that show its product is better than nothing (i.e., a placebo). Somehow Vedantam learned that the maker of Prozac (Lilly) had to conduct five trials to obtain two that produced favorable results, and the makers of Paxil and Zoloft had to conduct even more.

That antidepressants are little more placebos was confirmed yet again in 2008 by another research team. They based this conclusion on data from all clinical trials submitted to the FDA for licensing of Prozac, Paxil, Effexor, and Serzone. The findings, published in the online journal PLoS, or Public Library of Science, provided a grim reminder of the FDA’s lax standards. The drug company-sponsored trials required for FDA approval lasted no more than six weeks; yet people typically take antidepressants for years. No wonder it took nearly two decades for adverse reactions to come to light. Click here for side effects.

Fast forward to the present and the question of why the national media are currently reporting the antidepressant/placebo story. Well, once again it was not a single study that produced negative results for these drugs but a meta-analysis of many antidepressant vs placebo clinical trials through 2009. It was published early this year—this time in a high-profile, Journal of the American Medical Association, which typically gets national media attention. The unsurprising conclusion: The benefit of antidepressant medication “may be minimal or nonexistent, on average, in [adult] patients with mild or moderate symptoms [of depression].” This analysis was funded by grants from the National Institute of Mental Health.

Although the authors left the door open for the appealing idea that drugs work for severe depression, this possibility was shot down in the above-mentioned 2008 PLoS analysis. Here’s how the authors of that analysis put it: “Additional analyses indicated that the apparent clinical effectiveness of the antidepressants among these most severely depressed patients reflected a decreased responsiveness to placebo rather than an increased responsiveness to antidepressants.”

The mountain of evidence against antidepressants has yet to make a big difference in physician prescribing practices. They remain among the most prescribed drugs in the U.S. But a predictable change is already occurring. Now that the older antidepressants are going off patent, physicians are turning to the newer, more expensive versions like Pristiq and Effexor (as instructed by drug industry promotional campaigns). Is there any reason for us to trust them?

For more information
Read about the efforts to keep drug companies from hiding their studies with negative results (click here) and the short-comings in the FDA new-drug approval process (click here).

Maryann Napoli, Center for Medical Consumers©

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