Bipolar disorders. The central feature differentiating disruptive mood dysregulation disor- der and bipolar disorders in children involves the longitudinal course of the core symptoms. In children, as in adults, bipolar I disorder and bipolar H disorder manifest as an episodic illness with discrete episodes of mood perturbation that can be differentiated from the child’s typical presentation. The mood perturbation that occurs during a manic episode is distinctly different from the child’s usual mood. In addition, during a manic episode, the change in mood must be accompanied by the onset, or worsening, of associated cognitive, behavioral, and physical symptoms (e.g., distractibility, increased goal-directed activity), which are also present to a de- gree that is distinctly different from the child’s usual baseline. Thus, in the case of a manic ep- isode, parents (and, depending on developmental level, children) should be able to identify a distinct time period during which the child’s mood and behavior were markedly different from usual. In contrast, the irritability of dismptive mood dysregulation disorder is persistent and is present over many months; while it may wax and wane to a certain degree, severe ini- tability is characteristic of the child with disruptive mood dysregulation disorder. Thus, while bipolar disorders are episodic conditions, disruptive mood dysregulation disorder is not. In fact, the diagnosis of disruptive mood dysregulation disorder cannot be assigned to a child or who has ever had a manic or hypomanic episode lasting more than 1 day. Another central is the presence of elevated or expansive mood and grandiosity. These symptoms are common features of mania but are not characteristic of disruptive mood dysregulation disorder.
Oppositional defiant disorder. While symptoms of oppositional defiant disorder typi- cally do occur in children with disruptive mood dysregulation disorder, mood symptoms of disruptive mood dysregulation disorder are relatively rare in children with opposi- tional defiant disorder. The key features that warrant the diagnosis of disruptive mood fiant disorder are the presence of severe and frequently recurrent outbursts and a persis- tent disruption in mood between outbursts. In addition, the diagnosis of disruptive mood dysregulation disorder requires severe impairment in at least one setting (i.e., home, school, or among peers) and mild to moderate impairment in a second setting. For this rea- son, while most children whose symptoms meet criteria for disruptive mood dysregula- disorder, the reverse is not the case. That is, in only approximately 15% of individuals with be met. Moreover, even for children in whom criteria for both disorders are met, only the diagnosis of disruptive mood dysregulation disorder should be made. Finally, both the prominent mood symptoms in disruptive mood dysregulation disorder and the high risk for depressive and anxiety disorders in follow-up studies justify placement of disruptive mood dysregulation disorder among the depressive disorders in DSM-5. (Oppositional defiant disorder is included in the chapter "Disruptive, Impulse-Control, and Conduct
Disorders") This reﬂects the more prominent mood component among individuals with disruptive mood dysregulation disorder, as compared with individuals with oppositional defiant disorder. Nevertheless, it also should be noted that disruptive mood dysregulation disorder appears to carry a high risk for behavioral problems as well as mood problems.