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DSM5: Double Standards, Part 1

August 29th, 2013 by drcoplan

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A double standard is defined as “the application of different sets of principles for similar situations” (http://en.wikipedia.org/wiki/Double_standard ). Double standards are usually regarded as “unfair” at best, and intellectually or morally questionable at worst. There are times when a double standard may be warranted (see my next post), but by and large the burden of proof lies with the person who claims the right to impose a double standard. Unfortunately, there are at least three opportunities for double standards in the DSM5, and the APA seems to have gotten it wrong all three times. We will discuss two of those situations here. The third situation is the topic of a following post.

In our last post (“The DSM: An idea whose time has come…. and gone?”), we stated that the DSM5 retains a symptom-oriented classification scheme, without regard for biological markers. In fact, this is not entirely true. When rewriting the definitions of various disorders and deciding how to group them, the editors of the DSM5 reviewed the scientific data on eleven “scientific indicators,” including “shared neural substrates, family traits, genetic risk factors, specific environmental risk factors, biomarkers, temperamental antecedents, abnormalities of emotional or cognitive processing, symptom similarity, course of illness, high comorbidity, and shared treatment response,” and used these data as “empirical guidelines to inform decision making by the work groups and the task force about how to cluster disorders to maximize their validity and clinical utility.” This is laudable, and forward-thinking. But after consulting these data and interpreting them for their own purposes, the committee removed these scientific validators from consideration by the practicing clinician, who must work from the clinical descriptors alone. The clinician’s role is reduced from that of a holistic diagnostician to that of an applier of rules. The clinician’s task is not to decide “Does my patient have such-and-such diagnosis, based on the totality of the presentation (including, perhaps, the patient’s early developmental history, or cognitive profile)?”, but “Does my patient meet DSM criteria for such-and-such diagnosis?” – an important but nevertheless more constricted role. What’s good for the working groups – the opportunity to incorporate biomedical data into the formulation of a diagnosis — ought to have been good for the end-user of the DSM as well, but the editors of the DSM felt otherwise.

Astonishingly, the editors of the DSM attempt to justify this double standard by invoking another double standard: “Until incontrovertible etiological or pathophysiological mechanisms are identified to fully validate specific disorders or disorder spectra, the most important standard for the DSM-5 disorder criteria will be their clinical utility for the assessment of clinical course and treatment response of individuals grouped by a given set of diagnostic criteria.” In other words, despite the acknowledged limitations of a classification scheme based on clinical categories (“It is impossible to capture the full range of psychopathology in the categorical diagnostic categories that we are now using”), these categories remain the bedrock of the DSM. Biological, epidemiological, and neuropsychological data, on the other hand, are deemed off-limits to the end-user of the DSM unless they rise to the level of being “incontrovertible.” Clearly, clinical criteria are being given an easy pass, while biomedical data are expected to clear a much higher bar.

The editors may be correct in stating “it is premature scientifically to propose alternative definitions for most disorders,” but no one was asking for that. The editors of the DSM5 created an artificial “either-or” situation: “Since a complete description of the underlying pathological processes is not possible for most mental disorders, it is important to emphasize that the current diagnostic criteria are the best available description of how mental disorders are expressed.” The editors had nothing to lose by adding the best available biomedical data to the mix. Ultimately, the two systems of classification (symptom-based and brain-based) will be complementary (at least, they ought to be!), and will co-exist for a very long time. Delaying the inclusion of biomedical data until they become “incontrovertible,” and provide “a complete description of underlying pathological processes” means putting it off forever. Some of us don’t have quite that long to wait.

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