A new, extremely worrying study found that a third of meta-analyses related to antidepressant studies are written by pharma industry employees. Aside from signaling a massive conflict of interests, this raises new questions about the efficiency and safety of new antidepressants.

Tom Varco/Wikimedia Commons, CC BY-SA 3.0

In September, a study about the antidepressant Paxil made big news; the study reported that Paxil, once thought to be safe, was proven unsafe at least for teenagers. Paxil, or as it is also known, Paroxetine, has some serious side effects – nausea in 26% of cases, diarrhea or constipation in 14 and 12% respectively, loss of appetite, headaches and so on. Of course, according to studies conducted by the company that produced the drug, it was safe. The original trial, known as Study 329, is but one high-profile example of pharmaceutical industry tainting the results of scientific research in a very delicate field.

The latest study, published in the Journal of Clinical Epidemiology, evaluated 185 meta-analyses, and came up with some dire results – a third of them were written by big pharma employees. In total, about 80% had some connection to a major pharma company, either through scholarships, funding or research grants.

“We knew that the industry would fund studies to promote its products, but it’s very different to fund meta-analyses,” which “have traditionally been a bulwark of evidence-based medicine,” says John Ioannidis, an epidemiologist at Stanford University School of Medicine and co-author of the study. “It’s really amazing that there is such a massive influx of influence in this field.

Especially worrying was that 7% of all researchers did not disclose their conflict of interest.

“There’s a certain pecking order of papers,” says Erick Turner, a professor of psychiatry at Oregon Health & Science University who was not associated with the research. “Meta-analyses are at the top of the evidence pyramid.” Turner was “very concerned” by the results but did not find them surprising. “Industry influence is just massive. What’s really new is the level of attention people are now paying to it.”

Also, it’s not like this didn’t make a difference. You could see clear differences between papers written by independent researchers, and by pharma-associated researchers. The latter were 22 times less likely to have negative statements about a drug than those run by unaffiliated researchers.

“The meta-analyses that have industry links are very different than those that don’t have industry links,” Ioannidis says. Those with industry ties had much more favorable coverage and fewer caveats. “Conversely, when no employees were involved, almost 50 percent had caveats,” Ioannidis says.

We’ve got enough issues with publication bias as it is – exacerbating it through funding biases and non-disclosure of conflicts of interests is can make for some very unfortunate outcomes.