RDoC: New ways of thinking about diagnosis of neuropsychiatric disorders
RDoC (Research domain criteria initiative): The aim is to understand the nature of mental health and illness in terms of varying degrees of dysfunction in fundamental psychological/biological system (i.e. major domains of neurobehavioral functioning), rather than within established diagnostic categories.
RDoC Domains: negative valence systems, positive valence systems, cognitive systems, social processes, arousal and regulatory systems,
Some examples of RDoC constructs: reward responsiveness, reward prediction error, attention, perception, cognitive control, performance monitoring, social communication etc.)
RDoC: aims to address the heterogeneity in the current nosology by providing a biologically-based, rather than symptom-based, framework for understanding mental disorders
The question now becomes one of when and how to build a long-term framework for research that can yield classification based on discoveries in genomics and neuroscience as well as clinical observation, with a goal of improving treatment outcomes (Insel et al. 2010)
What does RDoC do?
Conceptualizes mental illnesses as brain disorders [of brain circuits]
Assumes that dysfunction in neural circuits can be identified with the tools of clinical neuroscience
The framework assumes that data from genetics and clinical neuroscience will yield biosignatures that will augment clinical symptoms and signs for clinical management
How would this work in practice?
Clinician could supplement a clinical evaluation of what we now call an “anxiety disorder” with data from functional or structural imaging, genomic sequencing, and laboratory-based evaluations of fear conditioning and extinction to determine prognosis and appropriate treatment, analogous to what is done routinely today in many other areas of medicine
How could RDoC alter clinical practice?
The critical test is how well new molecular and neurobiological parameters predict prognosis or treatment response.
What would be some examples of success?
if a BDNF polymorphism identifies people with anxiety syndromes who do not respond to behavior therapy
if a copy number variant defines a form of psychosis with high remission rates
if neuroimaging yields a subtype of a mood disorder that consistently responds to lithium
Conventional way of thinking about diagnosis:
Diagnosis is based on clinical observation: identifying symptoms that cluster together, determining when symptoms appear, resolve, recur, become chronic.
Problem: difficult to deconstruct clusters of complex behaviors and link them to neurobiological systems. By linking basic biological and behavioral components, it will become possible to construct valid, reliable phenotypes (measurable traits or characteristics) for mental disorders.
Mental disorders are biological disorders involving brain circuits that implicate specific domains of cognition, emotion, or behavior.