Psychiatric journals’ pro-pharma publication bias hides suicide risk of antidepressants

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A new study finds that top psychiatry journals are more likely to publish antidepressant studies with favourable results—and that these studies are more likely to include lead authors with financial ties to the pharmaceutical industry. Studies finding results unfavourable to industry are relegated to non-psychiatric journals and, occasionally, low-ranked psychiatric journals.

“Studies reporting favourable results were more frequently published in psychiatric than non-psychiatric journals and were more often conducted by lead authors with financial conflicts of interest (fCOI). Within psychiatric journals, lead-authors with fCOI published in journals with higher impact factor and ranking,” the researchers write.

The study was conducted by Martin Plöderl at Paracelsus Medical University in Salzburg, Austria, and Simone Amendola and Michael P. Hengartner at the Zurich University of Applied Sciences, Switzerland. In keeping with their findings, the study was published in a prestigious—but non-psychiatric—journal, the Journal of Clinical Epidemiology.

 

Critics sometimes argue that study quality is the main factor in publication—that it just so happens that all the favourable studies conducted by pharma are of good quality, while all the unfavourable studies by independent researchers are of poor quality.

However, the researchers found that study quality did not explain the selective publication they identified. Instead, it appears that top psychiatric journals tend to publish researchers who are funded by pharma, and thus find favourable results, whether the study is of good quality or not—and good quality studies by independent researchers, who are more likely to find unfavourable results, end up in the bin.

Hengartner sums it up succinctly on X:

“Studies of authors with fCOI were NOT of higher quality than studies of industry-independent lead-authors.”

The researchers warn that this creates a false image of the safety and efficacy of antidepressant drugs. If industry-funded studies, which find favourable results for antidepressants, are published in the top psychiatric journals, while studies of the same quality that are independent but find unfavourable outcomes are shunted into non-psychiatric and low-ranking journals, then the evidence base in the top journals of the specialty is biased and misleading.

Positive studies in top journals in the specialty are more likely to receive media coverage and be taken seriously by journalists, academics, and psychiatrists themselves. Thus, beginning with a biased set of studies creates an exponentially expanding bubble of misleading information.

In this particular study, Plöderl, Amendola, and Hengartner focused on observational studies of the link between antidepressants and suicide. Because death by suicide is a rare event, it is difficult to study in small, randomized controlled trials (RCTs), so observational studies—which follow larger groups of people over time—are our main source of information about this outcome.

Thus, in this context, studies that were considered “favourable” to industry were those that found no link between antidepressants and suicide, while “unfavourable” studies were those that did find such a link. (There were no studies that found antidepressants actually reduced suicide.)

The researchers identified 27 studies that met these criteria published between 1990 and 2020.

Studies that were published in psychiatric journals (typically by researchers with financial ties to pharma) found, on average, no link between antidepressants and suicide. Studies that were published in non-psychiatric journals (typically by independent researchers) found, on average, that antidepressants increased suicide. This was true for both death by suicide and suicide attempts:

“For suicides, the meta-analytic results of the 17 study results published in psychiatric journals indicated no significantly increased risk for patients treated with antidepressants (RE=1.20, 95%-CI=0.92 to 1.58) (Table 2). In contrast, the 10 study results published in non-psychiatric journals reported a significantly increased suicide risk (RE=1.83, 95%-CI=1.25 to 2.70), test for subgroup difference: p=0.05. Similar findings were found for suicide attempts as outcome and for suicides and suicide attempts combined, and subgroup differences were statistically significant (both p<0.01).”

Yet the quality of the studies in both psychiatric and non-psychiatric journals was about the same, and when the researchers accounted for quality in their analysis, it actually increased the selective publication effect they found rather than mitigating it:

“Mean study quality was almost identical for studies published in psychiatric and non-psychiatric journals (M=7.47, SD=1.62 vs. M=7.70, SD=0.95, t=0.41, df=25, p=0.69) and controlling for study quality in a meta-regression model provided similar or even stronger evidence for lower risk estimates in psychiatric journals compared to non-psychiatric journals (Table 3).”

The results for journal prestige were less powerful—higher-ranked journals were more likely to publish favourable studies, but once study quality was included in the analysis, this effect was no longer significant. However, higher-ranked journals were also more likely to publish researchers with financial ties to pharma—and this remained significant after adjusting for study quality.

Antidepressant drugs have been consistently linked to increased suicide attempts and deaths. Studies have repeatedly shown that antidepressants increase suicide risk, particularly for children and adolescents, with some studies finding more than doubling the risk of suicide and at least one analysis finding a sixfold increase.

Studies have also found that antidepressant drugs worsen outcomes in the long term, even after controlling for the baseline level of depression severity.

Indeed, Plöderl, Amendola, and Hengartner were unable to find even a single study that supported the idea that antidepressants reduce suicide, with the “favourable” studies in their research being those that found the drugs simply don’t increase suicide. Yet, as they write, antidepressants are often given to those with severe depression and those at the highest risk for suicide, with the reasoning that the drugs will somehow reduce this risk—despite the lack of evidence for any such effect.

“Antidepressant treatment is often considered important in the prevention of suicide, especially in adults with depression, even though the best evidence from meta-analyses of RCTs and observational studies indicates that antidepressant use has no clear effect on suicidal behaviour or that it may even increase suicide risk,” they write.

They add that in this context, antidepressant use is based on “unsubstantiated claims” of suicide reduction, despite the possibility that the drugs actually increase it, making the use of these drugs a public health issue that needs to be addressed:

“That antidepressant use may increase suicide risk thus potentially poses a serious public health issue given the widespread prescription of these drugs and unsubstantiated claims to the contrary within academic psychiatry.”

Plöderl, Amendola, and Hengartner conclude that the research base from psychiatric journals is biased, with selective publication of favourable results by researchers with financial ties to pharma, which has nothing to do with study quality. They write that researchers and clinicians need to read studies about antidepressants and suicide risk in non-psychiatric journals to obtain an unbiased view of the evidence.

Ultimately, Plöderl, Amendola, and Hengartner write that independent researchers conclude that the drugs increase suicide risk. Psychiatry’s denial of this fact through selective publication of favourable industry-sponsored studies has led to the current public health crisis of increased suicide deaths due to antidepressant use.

 

 

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Plöderl, M., Amendola, S., Hengartner, M. P. (2023). Observational studies of antidepressant use and suicide risk are selectively published in psychiatric journals. Journal of Clinical Epidemiology. Published online August 04, 2023. DOI:https://doi.org/10.1016/j.jclinepi.2023.07.015 (Link)

 

Editor’s Note: Part of MITUK’s core mission is to present a scientific critique of the existing paradigm of care. Each week we will be republishing Mad in America’s latest blog on the evidence supporting the need for radical change.

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