A contentious study of chronic fatigue syndrome therapies has been mired in controversy for years. Its findings are being debunked again.

A Study of Chronic Fatigue Syndrome Therapies Is Debunked (Again)


Two widely prescribed treatments for chronic fatigue syndrome — cognitive behavior therapy, and a steady increase in activity known as “graded exercise therapy” — failed to lead to any recovery in patients. That’s the stark conclusion of a new reanalysis of data from the so-called PACE trial, the largest study of treatments for the illness, also known as myalgic encephalomyelitis, or ME/CFS.

The claims made by the PACE trial research were "highly misleading to clinicians and patients," the new analysis concluded.

The claims made by the PACE trial research were “highly misleading to clinicians and patients,” the new analysis concluded.

The PACE trial’s main results were published in The Lancet in 2011 and the journal Psychological Medicine in 2013. In the latter paper, the authors claimed that 22 percent of those who received either treatment “recovered,” about three times the rate in the study’s two other groups. The trial’s results have been hugely influential around the world. In the United States, the Centers for Disease Control and Prevention as well as major medical centers like the Mayo Clinic and Kaiser Permanente have long promoted the therapies, as Undark reported in a recent investigation.

But the trial has been mired in controversy for years. According to a growing chorus of well-regarded scientists and other experts, it suffered from egregious and disqualifying flaws. In the PACE trial protocol, the authors outlined four criteria that participants needed to meet in order to be considered “recovered.” In the 2013 paper, they dramatically weakened all four criteria, making it far easier to reach the “recovery” thresholds. In a bizarre paradox, some participants even qualified as “recovered” on two of the four criteria — measures of fatigue and physical function — at the start of the study, before undergoing any treatment at all.

For years, the PACE authors rejected requests from patients to release their raw trial data, which would have allowed others to calculate the results per the original protocol definition of “recovery.” Last summer, a British court ordered Queen Mary University of London — the home base of the lead PACE investigator, psychiatrist Peter White — to make the data from the $6 million trial available to the public. An independent group of researchers, using this newly released information, published the reanalysis last week in the journal Fatigue: Biomedicine, Health & Behavior.

In contrast to the results reported in the 2013 paper, the reanalysis found only single-digit rates of “recovery” for all four groups in the study. Moreover, there were no statistically significant benefits for cognitive behavior therapy (CBT) and graded exercise therapy (GET), the two interventions long promoted by the PACE investigators. “The claim that patients can recover as a result of CBT and GET is not justified by the data, and is highly misleading to clinicians and patients considering these treatments,” concluded the reanalysis.

Dr. White and his PACE colleagues did not respond to e-mails seeking comment. Neither did Robin Murray, a professor of psychiatric research at King’s College London and the U.K. editor of Psychological Medicine.

NOTE: The author of this post has played an advocacy role in working with physicians and patient groups to challenge the efficacy of graded exercise and cognitive behavior therapies for the treatment of chronic fatigue syndrome.

CORRECTION: A previous version of this article stated that a new analysis of a 2013 paper had concluded that the chronic fatigue syndrome therapies examined in that paper provided “no benefit.” However, the new analysis focused only on claims of “recovery,” and did not examine whether the therapies provided other benefits. The article’s subhead also originally referred to a 2011 study, but the 2011 article in The Lancet was a different PACE-related paper that was not the subject of the new reanalysis.

David Tuller is a lecturer in public health and journalism at the University of California, Berkeley, where he receives support from a Kaiser Permanente grant to the Graduate School of Journalism.