Twenty volunteers with no history of psychiatric problems were recruited, half of whom were given the drug Zoloft. The other half were given an antidepressant that, unlike Zoloft and Prozac, does not selectively target the brain chemical serotonin. Each group took their respective drug for two weeks and then, shortly thereafter, switched to the other.
Healy had designed his “healthy volunteer study” to compare the psychological experience of being on a serotonin antidepressant versus a non-serotonin antidepressant, but before he knew it, two of his volunteers became dangerously agitated and suicidal. Both were taking the SSRI drug. The adverse reactions couldn’t easily be blamed on psychological instability ? these were healthy volunteers. And the rate of 10 percent made it clear that such results were not so rare as to be incidental.
Some months later, when serving as an expert witness in a civil action against Zoloft’s manufacturer, Pfizer, Healy discovered an unpublished study from the 1980s in which healthy female volunteers were given either Zoloft or a placebo. The study was canceled four days later, after all those taking Zoloft began complaining of agitation and apprehension.