The lawsuit opens a window into the ongoing debate about just how effective and safe the many newer-generation antidepressants are — drugs including the huge blockbusters Zoloft, Prozac, Paxil and Effexor.
These medicines, approved starting in the late 1980s, were thought to have less-dangerous side effects than early antidepressants. Over time, the newer antidepressants were increasingly prescribed by primary care doctors, not just psychiatrists.
Pharmaceutical companies marketed the drugs heavily, with very-positive ads targeting consumers. Millions, many with just mild or temporary depression, asked their family doctor for a prescription. Sales grew steadily, declined for several years when the drugs were linked to suicidal thoughts, then rose again the last few years.
Today, antidepressants are the ninth-most popular type of prescription medicine, with annual sales topping $20 billion worldwide, according to health data firm IMS Health.
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 With colleagues, he reviewed numerous studies of popular antidepressants, including unpublished studies obtained using the Freedom of Information Act.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.
Linda A. Johnson can be followed at http://twitter.com/LindaJ_onPharma