Irritability and emotional dysregulation are recognized as serious aspects of psychopathology seen in in pediatric psychiatric patients. While various behavioral as well as psychopharmacological interventions have shown some efficacy in improving irritability and emotional dysregulation, there are no data determining the neurobiological mechanism of effect at the neural level. Previous studies have demonstrated that heightened amygdala response to negative emotional stimuli is closely related to irritability and emotional dysregulation in children and adolescents. Also, there are studies showing administration of oxytocin can decrease the heightened amygdala response to negative emotional stimuli across various psychiatric diagnoses. This study is a double-blind randomized trial of oxytocin for irritability and emotional dysregulation in the pediatric population. Neuroimaging modalities of fMRI and MEG are employed to probe the neuro-circuitry changes occurring as a result of the oxytocin intervention, specifically including heightened amygdala response to negative emotional stimuli and dysfunctional fronto-amygdala connectivity. The investigators will also investigate the genetic sequence of the oxytocin receptor in the study participants and its relationship with symptom profile and neural activity changes. Children and adolescents (age 10-18) with a diagnosis of disruptive mood and/or behavior disorders (including Attention Deficit/Hyperactivity Disorder [ADHD], Oppositional Defiant Disorder [ODD], Conduct Disorder [CD], and Disruptive Mood Dysregulation Disorder [DMDD]), and clinically significant levels of irritability and emotional dysregulation as measured by the Affective Reactivity Index Scale (score>/= 4).