Structural Neuroimaging of Brain Circuits: Some implications in Treating Psychiatric Conditions with Neuromodulation Approaches - Could Research Domain Criteria (RDoC) and Diagnostic and Statistical Manual of Mental Disorders (DSM) approaches be Integrated?

Modern neuroscience has produced a paradigm shift in biomedical sciences with important implications for psychiatry. In the 1990s, a new hypothesis was formulated, namely that psychiatric disorders are associated with altered brain circuitries and thus could be viewed as disorders of brain connectivity. In this paradigm, brain circuitries are considered putative biomarkers (or endophenotypes) in psychiatric disorders. The neural systems approach in psychiatric clinical research aims to identify well-understood neural systems in psychiatric conditions and to determine whether these neural systems are correlated with specific behaviors as well as with specific genotypes. These three issues can be addressed currently with the aid of neuroimaging in clinical psychiatric studies. Although it is not yet feasible for a diagnosis in psychiatry to be addressed at a brain circuitry level, neurocircuitry has become a major emphasis in psychiatric research. This is reflected clearly in the RDoC (Research Domain Criteria) framework, which integrates multiple levels of information in different domains of human biology and functioning – from genes to behavior – to investigate mental health and dysfunction. Although it is not a diagnostic instrument, the RDoC could be of great use to psychiatrists in enhancing their understanding of the behavioral dimensions in which a given patient may be strong or weak. A clinician psychiatrist or psychotherapist could use this information to sharpen and tailor a therapeutic intervention for a patient. Thus, the utilization of dimensional tools (such as the RDoC) and categorical tools (such as the Diagnostic and Statistical Manual of Mental Disorders-5 or DSM-5) could be complementary and mutually reinforcing to benefit the patient. Using neuroimaging, we can identify brain circuits and stimulate them using transcranial magnetic stimulation (TMS) or deep brain stimulation (DBS) aimed at modulating their activity (neuromodulation) to treat psychiatric conditions such as refractory depression or obsessive-compulsive disorder (OCD).