“It just doesn’t work as well as you would think from reading the scientific literature”.
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But results from almost a quarter of these trials were never published, says Erick Turner, a psychiatrist and researcher at Oregon Health and Science University and an author of both the 2008 study on depression drugs and the new one on talk therapy.
Hollon and colleagues searched National Institutes of Health (NIH) databases to identify all randomized clinical trials that had received grants from the NIH and had tested the effects of psychotherapy against depression between 1972 and 2008. This leaves talk therapy with a modest 20-percent chance of making you feel better.
The basic problem arises because clinical studies of the treatments for depression with more positive outcomes are more likely to be published than studies with less favorable results.
Medical literature has overstated the benefits of talk therapy for depression, in part because studies with poor results have rarely made it into journals, researchers reported Wednesday.
Follow Elizabeth on Twitter and Instagram. “It’s like flipping a bunch of coins and only keeping the ones that come up heads”, Hollon says in a press release. Critics of antidepressants suggested people with depression to avoid drug treatment, on the basis of the new study. “Among 38 studies judged positive by the FDA, all but one were published in a way that agreed with those judgments”. Researchers of these studies often say their findings were not interesting enough. Moving forward, the authors of the latest study suggested that journals and groups that fund research should archive published and unpublished findings so that reporting bias can be corrected.
Study co-author Erik Turner comments, “This study shows that publication bias occurs in psychotherapy, mirroring what we’ve seen previously with antidepressants and other drugs”.
Hollon explains that, although studies are assessed through peer review, there are certain loopholes that allow the benefits of treatments to be overstated and possible risks to be understated. Using the unpublished data together with the published data, they conducted a series of meta-analyses from which they concluded that psychotherapy works, but that its effectiveness was inflated by publication bias. “Our findings indicate that psychological treatment is efficacious and specific, but, as is the case for antidepressants, less than the published literature conveys”.
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In the meantime, “clinicians, guidelines developers, and decision makers should be aware of overestimated effects of the predominant treatments for major depressive disorder”.
