Section on Mood Dysregulation and Neuroscience (SMDN)
SMDN focuses primarily on two severe pediatric mood disorders with significant public health impact: chronic, severe irritability and bipolar disorder (BD). Our studies of irritability include both youth with the DSM-5 diagnosis of Disruptive Mood Dysregulation Disorder (DMDD) and those whose irritability is more mild but still impairing. Our work consists of studies on the brain mechanisms underlying BD and irritability, and on testing novel psychological and pharmacological treatments for DMDD. We conduct pathophysiological research, based on systems neuroscience principles and techniques, with the goal of informing novel treatment development.
Our focus on irritability arose in response to questions about whether severely impairing irritability, without distinct manic episodes, should be considered to be a form of pediatric BD. To facilitate research on this question, we defined a syndrome called severe mood dysregulation (SMD); this research informed the DSM-5 discussions regarding DMDD. Our brain-based research, in concert with longitudinal and family studies, support the conclusion that, while both BD and chronic irritability are very impairing in youth, they are not manifestations of the same illness. That is, relatively few youth with severe irritability develop BD in adulthood. This conclusion has significant treatment implications, in that first-line treatments for BD and DMDD are likely to differ.
Indeed, since DMDD is a new diagnosis, few treatments have been tested. Much of our research is designed to elucidate the brain mechanisms mediating irritability, both in DMDD, where it is particularly severe, and in anxiety disorders, depression, attention deficit hyperactivity disorder, and BD, where irritability is also common. Our major technique for uncovering relevant brain mechanisms is fMRI, although we also use other neuroimaging techniques. The tasks that we use in the fMRI scanner focus on responses to frustration, face emotion processing, and attentional mechanisms. Based on these and related studies, we are developing and testing several novel psychological treatments, including computer-based treatments and cognitive behavioral therapy.
Bipolar disorder is a relatively rare, highly heritable illness with a distinct clinical presentation i.e., the manic episode. Thus, our BD research focuses on identifying BD-specific biological risk factors or risk markers present in youth and adults with BD, and in unaffected youth at risk for BD. Our specific focus, motivated by consistent behavioral deficits we identified and by the literature, is on identifying BD-specific neural dysfunction that affects face emotion processing and attentional function.