Evidence Based Medicine can be defined as the practice of applying the best available scientific evidence to clinical decision making. Triple-blind randomized placebo-controlled clinical trials and their meta-analyses are held in highest regard as scientific evidence. EBM is often allegedly seen as a ‘cookbook’ approach by critics due its insistence on scientifically proven treatment for defined diagnosis. However, this allegation that Evidence Based Medicine (EBM) recognizes only evidence from systematic research as the sole and exclusive criterion of clinical decisions is more of a straw-man derived from the manner of Evidence Based Medicine (EBM) hyper-enthusiasts, something that is counter to the actual spirit of EBM that its pioneers have espoused.
Evidence Based Medicine (EBM) has been labeled as a means of integrating individual clinical expertise with external clinical evidence [Sackett et al 1996]. Ranga Krishnan voiced a similar view in an interview with Medscape, being a vocal proponent of applying Evidence Based Medicine (EBM) to psychiatry, where he stressed that Evidence Based Medicine (EBM) is more than just a “cook book” and rather a contextualization of the best possible available information in a systematic fashion. EBM therefore argues for a synthetic approach in which clinical judgment and research evidence are balanced. This is all well and good. However, the balance that exists between clinical judgment and evidence in psychiatry differs significantly from the balance that exists in other medical specialties.
Let us first look at the general limitations of Evidence Based Medicine (EBM) that are applicable to all medical specialties but present with greater relevance in psychiatry.
1) Time lapse between study and publication
Articles submitted to scientific journals often have to undergo considerable waiting time before they see the light of publishing, which could be a year or even more. Additionally, the various committees which take these published studies into account and recommend treatment guidelines for various disorders take years to come up with a final document. In a rapidly developing field such as psychiatry, this means that any treatment guideline will be years behind the actual advancement of scientific knowledge.
2) Generalizability
Evidence-based guidelines are riddled with the problem of generalizing available evidence to populations at large or to treatment course and outcomes over a prolonged period of time. The extent of extrapolation will remain a troublesome question. This is all the more acute in psychiatry because individual factors affect illnesses and treatment response in ways that are poorly understood.
3) Publication bias
A strong bias exists in favor of publishing only trials with positive results. This means there will be a large amount of scientific evidence that has not been made accessible, and therefore cannot be taken into account by evidence-based medicine, and yet that unpublished data can be of significant impact.
The problem with applying EBM to psychiatry goes deeper than these limitations. It has to do with the very manner in which diagnostic system in psychiatry functions. DSM classifies psychiatric diseases into discrete disorders based on clinical signs and symptoms. These disorders are basically ‘symptom-complexes’ and not specific illnesses whose pathophysiology is distinctly worked out. We do not know the exact etiology of any psychiatric disorder. The integrity of this nosological method is challenged by several observations, such as the high rates of over-all and comorbidity of psychiatric disorders, lack of homogeneity in treatment response and the fact that a broad range of different DSM disorders respond to the same medications. EBM employs these very DSM diagnoses in attempt to create specified algorithms for treatment, and the diagnostic issues at hand makes the whole venture uncertain at a fundamental level.
Research driven by EBM is focused on treatment efficacy for a particular diagnosis, but what is required in clinical psychiatric practice is the alleviation of specific symptoms. Once this crucial aspect is recognized it is easy to see that the insistence that EBM should monopolize psychiatry can be very detrimental. Psychiatric practice remains as much art as it is science, and there should be no shame for psychiatrists to acknowledge that treatment rationales ought to be driven not just by diagnosis-based statistically driven protocols, but also by sensible and reasonable conjectures based on the knowledge of particulars of an individual patient.
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