Understanding the Mental Illness

Part of what I want to do with this blog is to help advertise certain movements in science, especially those that I find useful. Today I want to talk about the science around mental illness. Mental illness is a common and large public health burden, but we haven’t done a super great job at understanding, treating, and preventing these conditions given the amount of research that we have invested into the problem.

Image attributed to Davidmbusto

In 2008, the National Institute of Mental Health (which you may remember from “The Secret of NIMH”) began implementing a new strategy to studying mental illnesses. Basically, the old strategy was based around illnesses that were explicitly diagnosable according to the Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association. This manual serves as the standard classification of mental disorders used by mental health care professionals. Therefore, if you wanted to apply for a grant, you would have to say something like, “I’m studying schizophrenia, and here’s how I’m going to try to fix or understand, schizophrenia.”

The problem is that the DSM classifications allow for a huge amount of variance in how the illness manifests in any particular individual. This variance is probably due to a vast oversimplification in our classification because the brain is a complex beast. Thus, 5 different people diagnosed with schizophrenia may each have a unique underlying disorder in the brain. Since we’re trying to understand the biology and how to intervene mechanistically, it is very hard to make good progress if the names that we give mental illnesses do not perfectly reflect the variety of underlying mechanisms.

Enter RDOC (The research domain criteria)

Instead of studying a specific mental illness, the approach of the RDOC research framework is to establish dimensions of functioning underlying human behavior, and then studying those domains. You can check out the included domains here

So for instance, instead of studying bipolar disorder, which sometimes includes psychosis, you would study some specific attribute of psychosis and include individuals diagnosed with different diseases. Instead of assuming that we know anything about mental illness, we start by assuming that we know something about some more fundamental underlying process. We know, kind of, how visual perception works, so let’s study how in the world you can have a visual hallucination. The hope is to build up a much more thorough understanding of particular symptoms, while staying relatively agnostic about the mental illness itself.

Let me know what you think of the strategy!