RDoC Seeks to Redefine Addiction and Mental Health
There’s a movement afoot in psychiatry and psychology that has the potential to remake diagnosis and treatment of mental illness and addiction.
Called “Research Domain Criteria” (RDoC), the idea is straightforward but difficult to implement.
The practice of medicine is described as both an art and a science. The blend seems necessary because broad statistical measures have to be applied to specific patients. And this patient, the one sitting right here, is a complex mix of too many interrelated categories to capture completely by some rote recipe. Even clear, demonstrated-in-the-lab conditions like diabetes will present differently in different patients – based on genetics and lifestyle.
But in psychotherapy, perhaps the pendulum has swung too far into the ‘art’ and, as scientific understanding improves, we ought to look more toward the science side of the ledger. RDoC is an attempt to “scientize” the practice of psychological therapy and move it into the realm of biology. More science, less art.
With this in mind, the National Institutes of Mental Health (NIMH) has been promoting RDoC for some time.
Criticism of DSM-5
An example of why RDoC changes the landscape should clarify matters. In the DSM-5 (the diagnostic “bible” for mental health), schizophrenia is separate from unipolar and bipolar mood disorders. The diagnoses are based on how the patient presents and the symptoms they exhibit. The treatments (and the billing for those treatments) are also different, depending on symptoms. Lessening of symptoms is also the best we can do to evaluate how effective treatments are.
However, there is evidence that schizophrenia and the polar mood disorders actually have the same genetic basis. From a biological point of view, the disorders may have the same cause. RDoC highlights this model with the idea that we should treat the underlying causes instead of focusing on symptoms.
Using the diabetes analogy, the current state of affairs would be treating the symptoms of diabetes (excessive thirst, hunger, excessive urination and so on) and labeling an improvement in symptoms a valid treatment, instead of giving insulin to address the root cause.
Currently, DSM-5 contains lists of addiction disorders and labels them by severity of symptoms: If you match the criteria for an “alcohol use disorder” in this edition of the manual, you will be ranked by severity, and all the rest flows from that ranking – treatment recommendations, insurance billing, statistical reporting and others. It says nothing about a lab test for a biological marker indicating the cause of alcoholism and cannot differentiate someone who drinks because their peers pressure them from someone who drinks because they have an “alcoholic brain” or a genetic predisposition. No DNA tests are run; no metabolic studies are done.
This is made clear between editions of the DSM; the DSM-IV classified alcoholism one way, while the DSM-5 classifies it another. Printing a book with a new definition had the potential to increase the number of treatable cases by as much as 60 percent.
Is It Really that Bad?
Psychiatry and psychology aren’t going to disappear by revamping diagnostic criteria and making them fit clearer biological models. In fact, most professionals welcome this change. If lab values or standardized testing can make the situation clear and offer real comparisons between patients with divergent symptoms, they are all for it. The counter-challenge is to show the details.
It’s one thing to criticize therapy for mental illness on the basis of a lack of clarity and too much guesswork, but it’s another to replace it with something better. The chorus seems to be, “Give us the tools and we’ll use them.”
According to NIMH director Tom Insel, RDoC is more of a philosophical change than an immediate revamping of psychology and psychiatry:
It became immediately clear that we cannot design a system based on biomarkers or cognitive performance because we lack the data. In this sense, RDoC is a framework for collecting the data needed for a new nosology. But it is critical to realize that we cannot succeed if we use DSM categories as the "gold standard." The diagnostic system has to be based on the emerging research data, not on the current symptom-based categories ... That is why NIMH will be re-orienting its research away from DSM categories. Going forward, we will be supporting research projects that look across current categories – or sub-divide current categories – to begin to develop a better system.
The real advantage in finding diagnostic criteria that meet high-quality scientific standards is being able to test outcomes accurately. Dividing up patient populations by underlying causative factors means research studies more accurately compare apples to apples so that treatments can meet an objective standard. This alone would help us with, say, confidence: Given diagnosis X, treatment Y will work better than treatment Z. That’s a big step forward.