The original trial, known as Study 329, is but one high-profile example of pharmaceutical industry influence known to pervade scientific research, including clinical trials the U.S. Food and Drug Administration requires pharma companies to fund in order to assess their products. For that reason, people who read scientific papers as part of their jobs have come to rely on meta-analyses, supposedly thorough reviews summarizing the evidence from multiple trials, rather than trust individual studies. But a new analysis casts doubt on that practice as well, finding that the vast majority of meta-analyses of antidepressants have some industry link, with a corresponding suppression of negative results.

The latest study, published in the Journal of Clinical Epidemiology, which evaluated 185 meta-analyses, found that one third of them were written by pharma industry employees. “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.”

Almost 80 percent of meta-analyses in the review had some sort of industry tie, either through sponsorship, which the authors defined as direct industry funding of the study, or conflicts of interest, defined as any situation in which one or more authors were either industry employees or independent researchers receiving any type of industry support (including speaking fees and research grants). Especially troubling, the study showed about 7 percent of researchers had undisclosed conflicts 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.”