Nearly a third of antidepressant drug studies are never published in the medical literature, and nearly all of those happen to show that the drug being tested failed to work. And in some of the studies that are published, unfavorable results have been recast to make the medicine appear more effective than it really is, according to a report released last month. The research team was led by Erick Turner of the Oregon Health & Science University. Even if this selective publication is not deliberate, this can be bad news for patients, they wrote in their report, published in the New England Journal of Medicine.
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 idea that unfavorable test results get quietly tucked away so nobody will see them — sometimes call the “file drawer effect” – has been around for years. The Turner team was able to study the question because the FDA has a registry in which companies are supposed to log details of their drug tests before the experiments are begun. They could see which experiments approved by the FDA between 1987 and 2004 were ultimately publicized in the medical literature and the main criteria the researchers planned to measure success.
Of the 74 studies that started for the 12 antidepressants, 38 produced positive results for the drug. All but one of those studies was published. However, when it came to the 36 studies with negative or questionable results, as assessed by the FDA, only three were published; another 11 were turned around and written as if the drug had worked. The team reported that “not only were positive results more likely to be published, but studies that were not positive” were often “published in a way that conveyed a positive outcome.” The following are examples:
- Of the seven negative studies done on GlaxoSmithKline’s Paxil, five were never published,
- Three studies for GSK’s Wellbutrin SR were found, but the two negative ones never made it to print.
- There were five studies for Pfizer’s Zoloft, but the three showing the drug to be ineffective were not published and a fourth study, ruled as questionable by the FDA, was written and published to make it appear that the drug worked.