The Value of Biomarkers Is Oversold In General Medicine
Implications for psychiatry and DSM 5
Posted June 6, 2011
John Ioannidis, MD, of Stanford University has published a paper with wide implications for medicine and also for psychiatry ( in the June 1 issue of Journal of the American Association). Ioannidis finds that many influential studies have made exaggerated claims purporting to find connections between biomarkers and medical illness. Overstated associations between specific diseases and specific genes (or other laboratory tests) have arisen from flaws in the study methods and/or data analyses and also the fact that journals selectively publish positive findings. The rush to regard false biomarkers as diagnostic tools can have dangerous consequences if this leads to unnecessary and potentially harmful early treatment.
How does this apply to psychiatric diagnosis? Certainly, we do not yet have any biomarkers to oversell. But the recent preventive- treatment- of- biomarker fad in medicine has been used to provide justification for the DSM 5 effort at the early diagnose of mild subclinical "mental disorders." Early diagnosis in psychiatry is being oversold as a tool that will allow preventive intervention to reduce the lifetime burden of illness. This is packaged as evidence of progress in psychiatry- an analogy to the early diagnosis and prevention efforts in medicine (much of which are based on identifying and treating biomarkers).
The DSM 5 ambition never made sense on its own terms. We have no biomarkers and no other way of distinguishing a real patient who is early in his course from the worried well who will do fine on their own and need no diagnosis or treatment. Early diagnosis in psychiatry would clearly result in enormous false positive rates leading to unnecessary and (especially when it comes to antipsychotic medication) quite dangerous treatments. Other ills of over-diagnosis include unnecessary stigma, inability to gret life and disability insurance and inappropriate absolving of personal responsibility because of the sick role. If everyday problems become falsely relabeled as "mental disorder", the current exaggerated rates of reported mental disorder would sky-rocket even further.
All this seems even more ridiculous when one considers that there is no effective treatment for any of DSM 5's newly created mild "disorders" - none that exceeds their extremely robust response to placebo. Most of the new "patients" will acquire stigma, cost, and drug complications in exchange for no benefit whatever.
All of this was perfectly obvious before Ionnidis' deflation of the biomarker hype in general medicine. But his report is yet another reminder (if one were needed) that however desirable is the goal of preventive psychiatry, its necessary tools are decades away. Early diagnosis does not make sense until we can do it accurately, with a low false positive rate. Early treatment does not make sense until it is a lot more effective than placebo and almost as safe.