An open letter to Psychological Medicine, again!

Last week, Virology Blog posted an open letter to the editors of Psychological Medicine. The letter called on them to retract the misleading findings that participants in the PACE trial for ME/CFS had “recovered” from cognitive behavior therapy and graded exercise therapy. More than 100 scientists, clinicians, other experts and patient organizations signed the letter.

Three days later, I received a response from Sir Robin Murray, the UK editor of Psychological Medicine. Here’s what he wrote:

Thank you for your letter and your continuing interest in the paper on the PACE Trial which Psychological Medicine published. I was interested to learn that Wilshire and colleagues have now published a reanalysis of the original data from the PACE Trial in the journal Fatigue: Biomedicine, Health & Behavior, a publication that I was not previously aware of. Presumably, interested parties will now be able to read this reanalysis and compare the scientific qualiity of the re-analysis with that of the original. My understanding is that this is the way that science advances.

This is an unacceptable response. Sir Robin Murray is misguided if he believes that science advances by allowing misleading claims based on manipulated data to stand in the literature. When researchers include participants who were already “recovered” on key indicators at baseline, the findings are by definition so flawed and nonsensical they must be retracted.

That the editors of Psychological Medicine do not grasp that it is impossible to be “disabled” and “recovered” simultaneously on an outcome measure is astonishing and deeply troubling. It is equally astonishing that the PACE authors now defend themselves, as noted in a New York Times opinion piece on Sunday, by arguing that this overlap doesn’t matter because there were also other recovery criteria.

In response to the comments from Psychological Medicine, we are reposting the open letter with 17 added individuals and 24 more organizations, for a total of 142 signatories altogether. These include two lawyers from Queen Mary University of London, the academic home of lead PACE investigator Peter White, along with other experts and ME/CFS patient groups from around the world.

Sir Robin Murray and Dr. Kenneth Kendler

Psychological Medicine

Cambridge University Press

University Printing House

Shaftesbury Road

Cambridge CB2 8BS

UK

Dear Sir Robin Murray and Dr. Kendler:

In 2013, Psychological Medicine published an article called “Recovery from chronic fatigue syndrome after treatments given in the PACE trial.”[1] In the paper, White et al. reported that graded exercise therapy (GET) and cognitive behavioural therapy (CBT) each led to recovery in 22% of patients, compared with only 7% in a comparison group. The two treatments, they concluded, offered patients “the best chance of recovery.”

PACE was the largest clinical trial ever conducted for chronic fatigue syndrome (also known as myalgic encephalomyelitis, or ME/CFS), with the first results published in The Lancet in 2011.[2] It was an open-label study with subjective primary outcomes, a design that requires strict vigilance to prevent the possibility of bias. Yet PACE suffered from major flaws that have raised serious concerns about the validity, reliability and integrity of the findings.[3] Despite these flaws, White et al.’s claims of recovery in Psychological Medicine have greatly impacted treatment, research, and public attitudes towards ME/CFS.

According to the protocol for the PACE trial, participants needed to meet specific benchmarks on four different measures in order to be defined as having achieved “recovery.”[4] But in Psychological Medicine, White et al. significantly relaxed each of the four required outcomes, making “recovery” far easier to achieve. No PACE oversight committees appear to have approved the redefinition of recovery; at least, no such approvals were mentioned. White et al. did not publish the results they would have gotten using the original protocol approach, nor did they include sensitivity analyses, the standard statistical method for assessing the impact of such changes.

Patients, advocates and some scientists quickly pointed out these and other problems. In October of 2015, Virology Blog published an investigation of PACE, by David Tuller of the University of California, Berkeley, that confirmed the trial’s methodological lapses.[5] Since then, more than 12,000 patients and supporters have signed a petition calling for Psychological Medicine to retract the questionable recovery claims. Yet the journal has taken no steps to address the issues.

Last summer, Queen Mary University of London released anonymized PACE trial data under a tribunal order arising from a patient’s freedom-of-information request. In December, an independent research group used that newly released data to calculate the recovery results per the original methodology outlined in the protocol.[6] This reanalysis documented what was already clear: that the claims of recovery could not be taken at face value.

In the reanalysis, which appeared in the journal Fatigue: Biomedicine, Health & Behavior, Wilshire et al. reported that the PACE protocol’s definition of “recovery” yielded recovery rates of 7 % or less for all arms of the trial. Moreover, in contrast to the findings reported in Psychological Medicine, the PACE interventions offered no statistically significant benefits. In conclusion, noted Wilshire et al., “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.”

In short, the PACE trial had null results for recovery, according to the protocol definition selected by the authors themselves. Besides the inflated recovery results reported in Psychological Medicine, the study suffered from a host of other problems, including the following:

*In a paradox, the revised recovery thresholds for physical function and fatigue–two of the four recovery measures–were so lax that patients could deteriorate during the trial and yet be counted as “recovered” on these outcomes. In fact, 13 % of participants met one or both of these recovery thresholds at baseline. White et al. did not disclose these salient facts in Psychological Medicine. We know of no other studies in the clinical trial literature in which recovery thresholds for an indicator actually represented worse health status than the entry thresholds for serious disability on the same indicator.

*During the trial, the authors published a newsletter for participants that included glowing testimonials from earlier participants about their positive outcomes in the trial.[7] An article in the same newsletter reported that a national clinical guidelines committee had already recommended CBT and GET as effective; the newsletter article did not mention adaptive pacing therapy, an intervention developed specifically for the PACE trial. The participant testimonials and the newsletter article could have biased the responses of an unknown number of the two hundred or more people still undergoing assessments—about a third of the total sample.

*The PACE protocol included a promise that the investigators would inform prospective participants of “any possible conflicts of interest.” Key PACE investigators have had longstanding relationships with major insurance companies, advising them on how to handle disability claims related to ME/CFS. However, the trial’s consent forms did not mention these self-evident conflicts of interest. It is irrelevant that insurance companies were not directly involved in the trial and insufficient that the investigators disclosed these links in their published research. Given this serious omission, the consent obtained from the 641 trial participants is of questionable legitimacy.

Such flaws are unacceptable in published research; they cannot be defended or explained away. The PACE investigators have repeatedly tried to address these concerns. Yet their efforts to date—in journal correspondence, news articles, blog posts, and most recently in their response to Wilshire et al. in Fatigue[8]—have been incomplete and unconvincing.

The PACE trial compounded these errors by using a case definition for the illness that required only one symptom–six months of disabling, unexplained fatigue. A 2015 report from the U.S. National Institutes of Health recommended abandoning this single-symptom approach for identifying patients.[9] The NIH report concluded that this broad case definition generated heterogeneous samples of people with a variety of fatiguing illnesses, and that using it to study ME/CFS could “impair progress and cause harm.”

PACE included sub-group analyses of two alternate and more specific case definitions, but these case definitions were modified in ways that could have impacted the results. Moreover, an unknown number of prospective participants might have met these alternate criteria but been excluded from the study by the initial screening.

To protect patients from ineffective and possibly harmful treatments, White et al.’s recovery claims cannot stand in the literature. Therefore, we are asking Psychological Medicine to retract the paper immediately. Patients and clinicians deserve and expect accurate and unbiased information on which to base their treatment decisions. We urge you to take action without further delay.

Sincerely,

Dharam V. Ablashi, DVM, MS, Dip Bact

Scientific Director

HHV-6 Foundation

Former Senior Investigator

National Cancer Institute

National Institutes of Health

Bethesda, Maryland, USA

James N. Baraniuk, MD

Professor, Department of Medicine

Georgetown University

Washington, D.C., USA

Lisa F. Barcellos, MPH, PhD

Professor of Epidemiology

School of Public Health

California Institute for Quantitative Biosciences

University of California, Berkeley

Berkeley, California, USA

Lucinda Bateman, MD

Medical Director

Bateman Horne Center

Salt Lake City, Utah, USA

Alison C. Bested, MD, FRCPC

Clinical Associate Professor

Faculty of Medicine

University of British Columbia

Vancouver, British Columbia, Canada

Molly Brown, PhD

Assistant Professor

Department of Psychology

DePaul University

Chicago, Illinois, USA

John Chia, MD

Clinician and Researcher

EVMED Research

Lomita, California, USA

Todd E. Davenport, PT, DPT, MPH, OCS

Associate Professor

Department of Physical Therapy

University of the Pacific

Stockton, California, USA

Ronald W. Davis, PhD

Professor of Biochemistry and Genetics

Stanford University

Stanford, California, USA

Simon Duffy, PhD, FRSA

Director

Centre for Welfare Reform

Sheffield, UK

Jonathan C.W. Edwards, MD

Emeritus Professor of Medicine

University College London

London, UK

Derek Enlander, MD

New York, New York, USA

Meredyth Evans, PhD

Clinical Psychologist and Researcher

Chicago, Illinois, USA

Kenneth J. Friedman, PhD

Associate Professor of Physiology and Pharmacology (retired)

New Jersey Medical School

University of Medicine and Dentistry of New Jersey

Newark, New Jersey, USA

Robert F. Garry, PhD

Professor of Microbiology and Immunology

Tulane University School of Medicine

New Orleans, Louisiana, USA

Keith Geraghty, PhD

Honorary Research Fellow

Division of Population Health, Health Services Research & Primary Care

School of Health Sciences

University of Manchester

Manchester, UK

Ian Gibson, PhD

Former Member of Parliament for Norwich North

Former Dean, School of Biological Sciences

University of East Anglia

Honorary Senior Lecturer and Associate Tutor

Norwich Medical School

University of East Anglia

Norwich, UK

Rebecca Goldin, PhD

Professor of Mathematics

George Mason University

Fairfax, Virginia, USA

Ellen Goudsmit, PhD, FBPsS

Health Psychologist (retired)

Former Visiting Research Fellow

University of East London

London, UK

Maureen Hanson, PhD

Liberty Hyde Bailey Professor

Department of Molecular Biology and Genetics

Cornell University

Ithaca, New York, USA

Malcolm Hooper, PhD

Emeritus Professor of Medicinal Chemistry

University of Sunderland

Sunderland, UK

Leonard A. Jason, PhD

Professor of Psychology

DePaul University

Chicago, Illinois, USA

Michael W. Kahn, MD

Assistant Professor of Psychiatry

Harvard Medical School

Boston, Massachusetts, USA

Jon D. Kaiser, MD

Clinical Faculty

Department of Medicine

University of California, San Francisco

San Francisco, California, USA

David L. Kaufman, MD

Medical Director

Open Medicine Institute

Mountain View, California, USA

Betsy Keller, PhD

Department of Exercise and Sports Sciences

Ithaca College

Ithaca, New York, USA

Nancy Klimas, MD

Director, Institute for Neuro-Immune Medicine

Nova Southeastern University

Director, Miami VA Medical Center GWI and CFS/ME Program

Miami, Florida, USA

Andreas M. Kogelnik, MD, PhD

Director and Chief Executive Officer

Open Medicine Institute

Mountain View, California, USA

Eliana M. Lacerda, MD, MSc, PhD

Clinical Assistant Professor

Disability & Eye Health Group/Clinical Research Department

Faculty of Infectious and Tropical Diseases

London School of Hygiene & Tropical Medicine

London, UK

Charles W. Lapp, MD

Medical Director

Hunter-Hopkins Center

Charlotte, North Carolina, USA

Assistant Consulting Professor

Department of Community and Family Medicine

Duke University School of Medicine

Durham, North Carolina, USA

Bruce Levin, PhD

Professor of Biostatistics

Columbia University

New York, New York, USA

Alan R. Light, PhD

Professor of Anesthesiology

Professor of Neurobiology and Anatomy

University of Utah

Salt Lake City, Utah, USA

Vincent C. Lombardi, PhD

Director of Research

Nevada Center for Biomedical Research

Reno, Nevada, USA

Alex Lubet, PhD

Professor of Music

Head, Interdisciplinary Graduate Group in Disability Studies

Affiliate Faculty, Center for Bioethics

Affiliate Faculty, Center for Cognitive Sciences

University of Minnesota

Minneapolis, Minnesota, USA

Steven Lubet

Williams Memorial Professor of Law

Northwestern University Pritzker School of Law

Chicago, Illinois, USA

Sonya Marshall-Gradisnik, PhD

Professor of Immunology

Co-Director, National Centre for Neuroimmunology and Emerging Diseases

Griffith University

Queensland, Australia

Patrick E. McKnight, PhD

Professor of Psychology

George Mason University

Fairfax, Virginia, USA

Jose G. Montoya, MD, FACP, FIDSA

Professor of Medicine

Division of Infectious Diseases and Geographic Medicine

Stanford University School of Medicine

Stanford, California, USA

Zaher Nahle, PhD, MPA

Vice President for Research and Scientific Programs

Solve ME/CFS Initiative

Los Angeles, California, USA

Henrik Nielsen, MD

Specialist in Internal Medicine and Rheumatology

Copenhagen, Denmark

James M. Oleske, MD, MPH

François-Xavier Bagnoud Professor of Pediatrics

Senator of RBHS Research Centers, Bureaus, and Institutes

Director, Division of Pediatrics Allergy, Immunology & Infectious Diseases

Department of Pediatrics

Rutgers New Jersey Medical School

Newark, New Jersey, USA

Elisa Oltra, PhD

Professor of Molecular and Cellular Biology

Catholic University of Valencia School of Medicine

Valencia, Spain

Richard Podell, MD, MPH

Clinical Professor

Department of Family Medicine

Rutgers Robert Wood Johnson Medical School

New Brunswick, New Jersey, USA

Nicole Porter, PhD

Psychologist in Private Practice

Rolling Ground, Wisconsin, USA

Vincent R. Racaniello, PhD

Professor of Microbiology and Immunology

Columbia University

New York, New York, USA

Arthur L. Reingold, MD

Professor of Epidemiology

University of California, Berkeley

Berkeley, California, USA

Anders Rosén, MD

Professor of Inflammation and Tumor Biology

Department of Clinical and Experimental Medicine

Division of Cell Biology

Linköping University

Linköping, Sweden

Peter C. Rowe, MD

Professor of Pediatrics

Johns Hopkins University School of Medicine

Baltimore, Maryland, USA

William Satariano, PhD

Professor of Epidemiology and Community Health

University of California, Berkeley

Berkeley, California, USA

Ola Didrik Saugstad, MD, PhD, FRCPE

Professor of Pediatrics

University of Oslo

Director and Department Head

Department of Pediatric Research

University of Oslo and Oslo University Hospital

Oslo, Norway

Charles Shepherd, MB, BS

Honorary Medical Adviser to the ME Association

Buckingham, UK

Christopher R. Snell, PhD

Scientific Director

WorkWell Foundation

Ripon, California, USA

Donald R. Staines, MBBS, MPH, FAFPHM, FAFOEM

Clinical Professor

Menzies Health Institute Queensland

Co-Director, National Centre for Neuroimmunology and Emerging Diseases

Griffith University

Queensland, Australia

Philip B. Stark, PhD

Professor of Statistics

University of California, Berkeley

Berkeley, California, USA

Eleanor Stein, MD, FRCP(C)

Psychiatrist in Private Practice

Assistant Clinical Professor

University of Calgary

Calgary, Alberta, Canada

Staci Stevens, MA

Founder, Exercise Physiologist

Workwell Foundation

Ripon, California, USA

Julian Stewart, MD, PhD

Professor of Pediatrics, Physiology and Medicine

Associate Chairman for Patient Oriented Research

Director, Center for Hypotension

New York Medical College

Hawthorne, NY, USA

Leonie Sugarman, PhD

Emeritus Associate Professor of Applied Psychology

University of Cumbria

Carlisle, UK

John Swartzberg, MD

Clinical Professor Emeritus

School of Public Health

University of California, Berkeley

Berkeley, California, USA

Ronald G. Tompkins, MD, ScD

Summer M Redstone Professor of Surgery

Harvard Medical School

Boston, Massachusetts, USA

David Tuller, DrPH

Lecturer in Public Health and Journalism

University of California, Berkeley

Berkeley, California, USA

Rosemary A. Underhill, MB, BS, MRCOG, FRCSE

Physician and Independent Researcher

Palm Coast, Florida, USA

Rosamund Vallings, MNZM, MB, BS

General Practitioner

Auckland, New Zealand

Michael VanElzakker, PhD

Research Fellow, Psychiatric Neuroscience Division

Harvard Medical School & Massachusetts General Hospital

Instructor, Tufts University Psychology

Boston, Massachusetts, USA

Mark VanNess, PhD

Professor of Health, Exercise & Sports Sciences

University of the Pacific

Stockton, California, USA

Workwell Foundation

Ripon, California, USA

Mark Vink, MD

Family Physician

Soerabaja Research Center

Amsterdam, Netherlands

Frans Visser, MD

Cardiologist

Stichting Cardiozorg

Hoofddorp, Netherlands

Tony Ward, MA (Hons), PhD, DipClinPsyc

Registered Clinical Psychologist

Professor of Clinical Psychology

School of Psychology

Victoria University of Wellington

Wellington, New Zealand

Adjunct Professor, School of Psychology

University of Birmingham

Birmingham, UK

Adjunct Professor, School of Psychology

University of Kent

Canterbury, UK

William Weir, FRCP

Infectious Disease Consultant

London, UK

John Whiting, MD

Specialist Physician

Private Practice

Brisbane, Australia

Carolyn Wilshire, PhD

Senior Lecturer

School of Psychology

Victoria University of Wellington

Wellington, New Zealand

Michael Zeineh, MD, PhD

Assistant Professor

Department of Radiology

Stanford University

Stanford, California, USA

Marcie Zinn, PhD

Research Consultant in Experimental Electrical Neuroimaging and Statistics

Center for Community Research

DePaul University

Chicago, Illinois, USA

Executive Director

Society for Neuroscience and Psychology in the Performing Arts

Dublin, California, USA

Mark Zinn, MM

Research Consultant in Experimental Electrophysiology

Center for Community Research

DePaul University

Chicago, Illinois, USA

New individuals added 23 March 2017

Norman E. Booth, PhD, FInstP

Emeritus Fellow in Physics

Mansfield College

University of Oxford

Oxford, UK

Joan Crawford, CPsychol, CEng, CSci, MA, MSc

Chartered Counselling Psychologist

Chronic Pain Management Service

St Helens Hospital

St Helens, UK

Lucy Dechene, PhD

Professor of Mathematics (retired)

Fitchburg State University

Fitchburg, Massachusetts, USA

Valerie Eliot Smith

Barrister and Visiting Scholar

Centre for Commercial Law Studies

Queen Mary University of London

London, UK

Margaret C. Fernald, PhD

Clinical and Research Psychologist

University of Maine

Orono, Maine, USA

Simin Ghatineh, MSc, PhD

Biochemist

London, UK

Alan Gurwitt, M.D.

Former Clinical Child Psychiatry Faculty Member

Yale Child Study Center, New Haven, Connecticut

University of Connecticut School of Medicine, Farmington, Connecticut

Harvard Medical School, Boston, Massachusetts

Co-author of primers on Adult and Pediatric ME/CFS

Clinician in Private Practice (retired)

Boston, Massachusetts, USA

Geoffrey Hallmann, LLB, DipLegPrac

Former Laywer, (Disability And Compensation)

Lismore, Australia

Susan Levine, MD

Clinician in Private Practice

New York, New York, USA

Visiting Fellow

Cornell University

Ithaca, New York, USA

Marvin S. Medow, Ph.D.

Professor of Pediatrics and Physiology

Chairman, New York Medical College IRB

Associate Director of The Center for Hypotension

New York Medical College

Hawthorne, New York, USA

Sarah Myhill MB BS

Clinician in Private Practice

Knighton, UK

Pamela Phillips, Dip, Dip. MSc MBACP (registered)

Counsellor in Private Practice

London, UK

Gwenda L Schmidt-Snoek, PhD

Researcher

Former Assistant Professor of Psychology

Hope College

Holland, Michigan, USA

Robin Callender Smith, PhD

Professor of Media Law

Centre for Commercial Law Studies

Queen Mary University of London.

Barrister and Information Rights Judge

London, UK

Samuel Tucker, MD

Former Assistant Clinical Professor of Psychiatry

University of California, San Francisco

San Francisco, California, USA

AM Uyttersprot, MD

Neuropsychiatrist

AZ Jan Portaels

Vilvoorde, Belgium

Paul Wadeson, Bsc, MBChB, MRCGP

GP Principal

Ash Trees Surgery

Carnforth, UK

ME/CFS Patient Organizations

25% ME Group

UK

Emerge Australia

Australia

European ME Alliance:

Belgium ME/CFS Association

Belgium

ME Foreningen

Denmark

Suomen CFS-Yhdistys

Finland

Fatigatio e.V.

Germany

Het Alternatief

Netherlands

Icelandic ME Association

Iceland

Irish ME Trust

Ireland

Associazione Malati di CFS

Italy

Norges ME-forening

Norway

Liga SFC

Spain

Riksföreningen för ME-patienter

Sweden

Verein ME/CFS Schweiz

Switzerland

Invest in ME Research

UK

Hope 4 ME & Fibro Northern Ireland

UK

Irish ME/CFS Association

Ireland

Massachusetts CFIDS/ME & FM Association

USA

ME Association

UK

ME/cvs Vereniging

Netherlands

National ME/FM Action Network

Canada

New Jersey ME/CFS Association

USA

Pandora Org

USA

Phoenix Rising

International membership representing many countries

Solve ME/CFS Initiative

USA

Tymes Trust (The Young ME Sufferers Trust)

UK

Wisconsin ME and CFS Association

USA

New Organizations added 23 March 2017

Action CND

Canada

Associated New Zealand ME Society

New Zealand

Chester MESH (ME self-help) group

Chester, UK

German Society for ME/CFS (Deutsche Gesellschaft für ME/CFS)

Germany

Lost Voices Stiftung

Germany

M.E. Victoria Association

Canada

ME North East

UK

ME Research UK

UK

ME Self Help Group Nottingham

UK

ME/CFS and Lyme Association of WA, Inc.

Australia

ME/CFS (Australia) Ltd

Australia

ME/CFS Australia (SA), Inc.

Australia

ME/CVS Stichting Nederland

Netherlands

ME/FM Myalgic Encephalomyelitis and Fibromyalgia Society of British Columbia

Canada

MEAction

International membership representing many countries

Millions Missing Canada

Canada

National CFIDS Foundation, Inc.

USA

North London ME Network

UK

OMEGA (Oxfordshire ME Group for Action)

UK

Open Medicine Foundation

USA





Quebec ME Association

Canada

The York ME Community

UK

Welsh Association of ME & CFS Support

UK

Organization added 29 March 2017

Supportgroup ME and Disability

(Steungroep ME en Arbeidsongeschiktheid)

Groningen, Netherlands

[1] White PD, Goldsmith K, Johnson AL, et al. 2013. Recovery from chronic fatigue syndrome after treatments given in the PACE trial. Psychological Medicine 43(10): 2227-2235.

[2] White PD, Goldsmith KA, Johnson AL, et al. 2011. Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial. The Lancet 377: 823–836

[3] Racaniello V. 2016. An open letter to The Lancet, again. Virology Blog, 10 Feb. Available at: https://www.virology.ws/2016/02/10/open-letter-lancet-again/ (accessed on 2/24/17).

[4] White PD, Sharpe MC, Chalder T, et al. 2007. Protocol for the PACE trial: a randomised controlled trial of adaptive pacing, cognitive behaviour therapy, and graded exercise, as supplements to standardised specialist medical care versus standardised specialist medical care alone for patients with the chronic fatigue syndrome/myalgic encephalomyelitis or encephalopathy. BMC Neurology 7: 6.

[5] Tuller D. 2015. Trial by error: the troubling case of the PACE chronic fatigue syndrome trial. Virology Blog, 21-23 Oct. Available at: https://www.virology.ws/2015/10/21/trial-by-error-i/ (accessed on 2/24/17)

[6] Wilshire C, Kindlon T, Matthees A, McGrath S. 2016. Can patients with chronic fatigue syndrome really recover after graded exercise or cognitive behavioural therapy? A critical commentary and preliminary re-analysis of the PACE trial. Fatigue: Biomedicine, Health & Behavior; published online 14 Dec. Available at: http://www.tandfonline.com/doi/full/10.1080/21641846.2017.1259724 (accessed on 2/24/17)

[7] PACE Participants Newsletter. December 2008. Issue 3. Available at: http://www.wolfson.qmul.ac.uk/images/pdfs/participantsnewsletter3.pdf (accessed on 2/24/17).

[8] Sharpe M, Chalder T, Johnson AL, et al. 2017. Do more people recover from chronic fatigue syndrome with cognitive behaviour therapy or graded exercise therapy than with other treatments? Fatigue: Biomedicine, Health & Behavior; published online 15 Feb. Available at: http://www.tandfonline.com/doi/full/10.1080/21641846.2017.1288629 (accessed on 2/24/17).

[9] Green CR, Cowan P, Elk R. 2015. National Institutes of Health Pathways to Prevention Workshop: Advancing the research on myalgic encephalomyelitis/chronic fatigue syndrome. Annals of Internal Medicine 162: 860-865.