Research Domain Criteria (RDoC) vs. DSM 'taxonomy' - pick one

[deltasigma]

Pick one. Why? Because the battle for grant money is ON! And the two paradigms seem so fundamentally at odds that it’s hard to see their co-existing.

RDoC is a project launched by the National Institute of Mental Health (NIMH) which will attempt to understand psych pathologies by taking a bottom up approach which specifically means starting from the biochemistry, then the neurology and finally how identifiable organic abnormalities correlate with pathologies.

If you think that executing such an approach might be less linear than it sounds, you’re not alone. But here’s their announcement.

n brief, the effort is to define basic dimensions of functioning (such as fear circuitry or working memory) to be studied across multiple units of analysis, from genes to neural circuits to behaviors, cutting across disorders as traditionally defined. The intent is to translate rapid progress in basic neurobiological and behavioral research to an improved integrative understanding of psychopathology and the development of new and/or optimally matched treatments for mental disorders.

The DSM series takes the top down approach. It’s like a taxonomy of psychiatric symptoms just like you would classify plants by the shape of their leaves, type of flower, etc.

Both approaches have merit and both are flawed. RDoC will (optimistically) take many years to fully quantify any disorders as we know them from the DSM. It doesn’t recognize any pathology for which a specific, reproducible neuro/biological basis cannot be identified. Finally it doesn’t even start to deal with intangible and unquantifiable issues. An article in Time gives a good overview of the conflict and concludes that we shouldn’t choose. As a clinician, in this in other passages, he adds the necessary human element.

What happens to the concept of PTSD [Post Traumatic Stress Disorder] once it is deconstructed into its Research Domains? Is there room for understanding the personal meaning of the traumatic event: for grief, guilt, shame, moral injury, intergenerational history or any other dimension of human experience which clinical experience and abundant research demonstrate to have significant importance in understanding and treating PTSD? And what has become of the patient in this debate?

Of course the DSM approach is also flawed as is often pointed out. The relationship between symptoms and and disease isn’t sharply defined and sometimes wrong. This can be misleading for research if you think you have one disorder that actually has 3 or 4 or more actual causes.

So it seems obvious that we need both approaches, but it’s equally obvious that the battle lines have been drawn - and by none other than the head of NIMH.

Unlike our definitions of ischemic heart disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure. In the rest of medicine, this would be equivalent to creating diagnostic systems based on the nature of chest pain or the quality of fever. Indeed, symptom-based diagnosis, once common in other areas of medicine, has been largely replaced in the past half century as we have understood that symptoms alone rarely indicate the best choice of treatment.Patients with mental disorders deserve better.