Domain Research

 

The Research Domain Criteria (RDoC) project is an initiative being developed by US National Institute of Mental Health. In contrast to the Diagnostic and Statistical Manual of Mental Disorders maintained by the American Psychiatric Association, RDoC aims to be a biologically-valid framework for understanding mental disorders: “RDoC is an attempt to create a new kind of taxonomy for mental disorders by bringing the power of modern research approaches in genetics, neuroscience, and behavioral science to the problem of mental illness.The 2008 NIMH Strategic Plan calls for NIMH to “Develop, for research purposes, new ways of classifying mental disorders based on dimensions of observable behavior and neurobiological measures.”The strategic plan continues:

Currently, the diagnosis of mental disorders is based on clinical observation—identifying symptoms that tend to cluster together, determining when the symptoms appear, and determining whether the symptoms resolve, recur, or become chronic. However, the way that mental disorders are defined in the present diagnostic system does not incorporate current information from integrative neuroscience research, and thus is not optimal for making scientific gains through neuroscience approaches. It is difficult to deconstruct clusters of complex behaviors and attempt to link these to underlying neurobiological systems. Many mental disorders may be considered as falling along multiple dimensions (e.g., cognition, mood, social interactions), with traits that exist on a continuum ranging from normal to extreme. Co-occurrence of multiple mental disorders might reflect different patterns of symptoms that result from shared risk factors and perhaps the same underlying disease processes.

To clarify the underlying causes of mental disorders, it will be necessary to define, measure, and link basic biological and behavioral components of normal and abnormal functioning. This effort will require integration of genetic, neuroscience, imaging, behavioral, and clinical studies. By linking basic biological and behavioral components, it will become possible to construct valid, reliable phenotypes (measurable traits or characteristics) for mental disorders. This will help us elucidate the causes of the disorder, while clarifying the boundaries and overlap between mental disorders. In order to understand mental disorders in terms of dimensions and/or components of neurobiology and behaviors, it will be important to:

Initiate a process for bringing together experts in clinical and basic sciences to jointly identify the fundamental behavioral components that may span multiple disorders (e.g., executive functioning, affect regulation, person perception) and that are more amenable to neuroscience approaches.
Develop reliable and valid measures of these fundamental components of mental disorders for use in basic studies and in more clinical settings.
Determine the full range of variation, from normal to abnormal, among the fundamental components to improve understanding of what is typical versus pathological.
Integrate the fundamental genetic, neurobiological, behavioral, environmental, and experiential components that comprise these mental disorders.In that post, Insel wrote: “Patients with mental disorders deserve better.” He would later elaborate on this point, saying “I look at the data and I’m concerned. … I don’t see a reduction in the rate of suicide or prevalence of mental illness or any measure of morbidity. I see it in other areas of medicine and I don’t see it for mental illness. That was the basis for my comment that people with mental illness deserve better.”

In their effort to resolve their issues with the new DSM, the NIMH launched the Research Domain Criteria Project (RDoC), based on four assumptions:

A diagnostic approach based on the biology as well as the symptoms must not be constrained by the current DSM categories,
Mental disorders are biological disorders involving brain circuits that implicate specific domains of cognition, emotion, or behavior,
Each level of analysis needs to be understood across a dimension of function,
Mapping the cognitive, circuit, and genetic aspects of mental disorders will yield new and better targets for treatment