In this issue of JAMA Psychiatry, Bebko et al1 present an innovative multisite study that uses both categorical and dimensional approaches to test associations between brain activity and symptoms in youth with severe emotional and behavioral dysregulation. Using functional magnetic resonance imaging (fMRI) and a reward-guessing task in 105 youth, the authors examined associations between brain activation and DSM-IV categories and between brain activation and dimensional measures of mania, depression, anxiety, and risk for bipolar spectrum disorder (BPSD, measured by the Parent General Behavior Inventory 10-Item Mania Scale [PGBI-10M]). During reward trials, Bebko et al found associations between frontal activation and both dimensional and categorical clinical measures. Specifically, using dimensional measures, they identified associations between PGBI-10M score and middle prefrontal cortical (mPFC) activity and between anxiety and dorsal anterior cingulate cortical (dACC) activity. However, they also report decreased ventrolateral prefrontal cortex (VLPFC) activity in youth categorized as having a disruptive behavior disorder (DBD, ie, conduct disorder and oppositional defiant disorder). Thus, when mapping patients’ symptoms onto brain activity, Bebko et al found that both dimensional and categorical approaches were useful.
Leibenluft E. Categories and Dimensions, Brain and BehaviorThe Yins and Yangs of Psychopathology. JAMA Psychiatry. 2014;71(1):15-17. doi:10.1001/jamapsychiatry.2013.2810