Pfizer Sued Over Zoloft’s Failure to Beat Placebo


A lawsuit filed Wednesday in San Jose, California seeks federal approval for two class-action lawsuits representing all U.S. users of the antidepressant Zoloft, accusing Pfizer of possessing research demonstrating Zoloft’s inefficacy over placebo and “deliberately withholding this information from consumers and then advertising this drug as very effective.”

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Of further interest:
Pfizer, Zoloft and the Vexing Placebo Effect (Pharmalot)
Pfizer, psychiatrists dispute lawsuit claiming antidepressant Zoloft is no better than placebo (Washington Post)
Pfizer disputes claim against antidepressant
(USA Today)

(From USA Today): Plumlee, 49, said in an exclusive interview that she took Zoloft from 2005 through 2008, while her doctor repeatedly increased the dose. He “swore it was working,” but she felt it didn’t help. Frustrated, and having gained 50 pounds as a side effect, the Watsonville, Calif., homemaker and mother of two teenagers quit Zoloft cold turkey and was hospitalized for six days with flu-like withdrawal symptoms.

“I kind of had a breakdown,” she said. “I just felt like I couldn’t hope.”

Four years later, Plumlee saw a 60 Minutes news program in which the key expert witness since hired for her case, Irving Kirsch, said his research on antidepressants indicated most improvement in depressed patients was from the placebo effect. That’s the benefit most patients get from believing a medicine works and from having doctors and nurses caring for them.

Kirsch, associate director of Harvard Medical School’s Program in Placebo Studies, has published a book and several medical journal articles on the effect. With colleagues, he reviewed numerous studies of popular antidepressants, including unpublished studies obtained using the Freedom of Information Act.

“The difference between drug and placebo is very small,” below the level that benefits patients, Kirsch concluded.

He said Pfizer produced two studies showing Zoloft worked better than placebo — the FDA’s requirement for approval — but most Zoloft studies showed its effect was the same as a placebo.

Dr. Michael Thase, who heads the mood and anxiety disorders program at the University of Pennsylvania’s medical school, said research by others using the same unpublished studies concluded antidepressants have “a modest effect over placebo,” on average about 15 percentage points.

That’s partly because the rate of study participants improving when they’re taking a placebo has been rising, said New York University’s Sussman.

Why? Back in the 1970s and ’80s, patients in clinical trials were generally hospitalized with severe depression. More recent trials mainly include outpatients — many with milder depression and so more likely to feel the placebo effect.

Plumlee, who watched the 60 Minutes program, saw it as proof she’d been right about Zoloft.

“It made me angry that … I had to be depressed for three extra years,” said Plumlee, who’s now doing much better with a new psychiatrist and different medication.

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Kermit Cole
Kermit Cole, MFT, founding editor of Mad in America, works in Santa Fe, New Mexico as a couples and family therapist. Inspired by Open Dialogue, he works as part of a team and consults with couples and families that have members identified as patients. His work in residential treatment — largely with severely traumatized and/or "psychotic" clients — led to an appreciation of the power and beauty of systemic philosophy and practice, as the alternative to the prevailing focus on individual pathology. A former film-maker, he has undergraduate and master's degrees in psychology from Harvard University, as well as an MFT degree from the Council for Relationships in Philadelphia. He is a doctoral candidate with the Taos Institute and the Free University of Brussels. You can reach him at [email protected].


  1. I think the idea of the lawsuit is quite interesting. They just need to throw in the blatant breach of fiduciary duty by Doctors who peddle the “chemical imbalance” “insulin for diabetes” and “take this for the rest of your life” nonsense…

    One item that confuses me though is the reference to anti-depressants working for those with Severe depression…when I read Kirsch’s book I thought he said no real difference there either. Or do people just keep the “very severe” depression as an option because people are too scared to admit they have no idea to help.

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  2. It’d be nice if something came out of this but I am pessimistic that it will. For one, as the USA Today article mentions, there is SCOTUS precedent that plaintiffs can’t recover alleged damages by claiming a company defrauded the FDA to get a drug approved. So even if the court were to agree with Kirsch, that would not result in a win. The silver lining is that Kirsch is involved as well as a prestigious law firm with an attorney specialized in antidepressant litigation. I am assuming he did his due diligence before working in the case and he sees the potential for a win. I experienced the withdrawal effects of sertraline (generic name of Zoloft) and clomipramine. The worst were the brain zaps that lasted for 1-2 weeks. After that, things were great. I also experienced the weight increase as well as kidney/liver damage and increased cholesterol levels. It puzzles me that these poisonous drugs are so widely prescribed.

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  3. Zoloft was the very first antidepressant my medical doctor put me on. I felt better the very next day! At the time I was unaware of the placebo effect. But after a couple of weeks it was everything back to usual so the doctor kept raising the dose to the point it would have knocked a horse for a loop, with absolutely no beneficial effect. There could have been chalk or flour in those capsules and they would have worked as well as the good ol’ zoloft. Of course, I experienced being totally out of touch with my emotions and feelings to the point that an atomic bomb could have gone off next to me and I would have never noticed.

    I hope that they can do something with this suit; if nothing else getting it out into the news will raise the awareness of some people and that will be a good thing.

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