Intended for healthcare professionals

Editor's Choice

Let’s proceed with caution

BMJ 2010; 340 doi: (Published 04 March 2010) Cite this as: BMJ 2010;340:c1266
  1. Fiona Godlee, editor, BMJ
  1. fgodlee{at}

    The lively response to last month’s editorial on chronic fatigue syndrome (BMJ 2010;340:c738, doi:10.1136/bmj.c738) brings home the inadequacy of our current understanding of this condition, or group of conditions. The responses from patients, carers, and clinicians remind us that we remain largely in the dark about its causes and prognosis, there are no accepted diagnostic tests, and treatment options are limited ( Sufferers must also deal with social and (if they are doctors) professional stigmatisation, as dermatologist Stephanie Munn experienced (doi:10.1136/bmj.c1179).

    Little wonder if many who live or work with chronic fatigue syndrome leapt at the news last October that scientists in Nevada had found a “highly significant association” between the condition and a newly discovered retrovirus, xenotropic murine leukaemia virus-related virus (XMRV). The case-control study published in Science was trumpeted, especially by the authors, as having found the cause of chronic fatigue syndrome, with promises of a diagnostic test and treatments to follow.

    As an epidemiologist, Cathie Sudlow’s initial response was sceptical, quickly confirmed when she saw that the paper lacked basic methodological information (doi:10.1136/bmj.c1260). “Where were the details of the characteristics and selection procedures for the cases and controls, or of blinding of researchers to the case-control status of the samples? Where was the discussion of the potential role of bias and confounding?”

    She and others sent electronic letters to the journal. Four months on, these have yet to appear. Meanwhile, and sadly for those whose hopes had been raised, the study has been refuted by three further case-control studies, one of them in the BMJ (doi:10.1136/bmj.c1018). Myra McClure and Simon Wessely point out that claims of association between retroviruses and diseases often fail to withstand the test of time (doi:10.1136/bmj.c1099).

    The paper by Van Kuppeveld and colleagues is an unusual paper for the BMJ to publish. As our research highlights page explains, we would usually reject a small case-control study examining the prevalence of a virus in 20 year old blood samples. Instead we fast tracked it. We did this because it’s about an important and debilitating syndrome that’s often seen by generalists and because we felt it added to an important and highly controversial debate. We and our reviewers also thought it was well done.

    So yes, let’s have more research into chronic fatigue syndrome, but let’s make sure it’s good enough research.

    We’re all under pressure to innovate, so we need to ensure as far as possible that innovation brings improvement. This may not be the case with the new edition of America’s (and hence the world’s) Diagnostic Criteria for Psychiatric Disorders. Three years in the drafting, DSM-V is now out for consultation with a view to publication in 2013.

    Our editorialist cries caution (doi:10.1136/bmj.c1168). DSM-IV was unwittingly responsible, says Allen Frances, for three “epidemics” of overdiagnosis. Rates of attention deficit hyperactivity disorder, autism, and childhood bipolar disorders shot up when it was published, fuelled not only by DSM-IVs more inclusive diagnostic criteria but by zealous marketing of drugs to doctors and the public.

    Now DSM-V threatens worse. It widens the criteria for several existing diagnoses and creates five new ones: binge eating, mixed anxiety depression, minor neurocognitive problems, risk of psychosis, and temper dysregulation. This could “expand the territory of mental disorder and thin the ranks of the normal,” exposing vast numbers of new “patients” to avoidable harm.


    Cite this as: BMJ 2010;340:c1266