Mood swings is a popular term that is nonspecific and not part of DSM-IV-TR diagnostic criteria for BD. The complaint of “mood swings” may reflect severe mood lability of pediatric patients with BD. This mood lability is best described by the Kiddie-Mania Rating Scale (K-MRS) developed by Axelson and colleagues as “rapid mood variation with several mood states within a brief period of time which appears internally driven without regard to the circumstance.” On K-MRS mood lability items, children with mania typically score:
Moderate—many mood changes throughout the day, can vary from elevated mood to anger to sadness within a few hours; changes in mood are clearly out of proportion to circumstances and cause impairment in functioning
Severe—rapid mood swings nearly all of the time, with mood intensity greatly out of proportion to circumstances
Extreme—constant, explosive variability in mood, several mood changes occurring within minutes, difficult to identify a particular mood, changes in mood radically out of proportion to circumstances.
Patients with BD typically exhibit what is best described as a “mood cycle”—a pronounced shift in mood and energy from 1 extreme to another. An example of this would be a child who wakes up with extreme silliness, high energy, and intrusive behavior that persists for several hours and then later in the day becomes sad, depressed, and suicidal with no precipitant for either mood cycle. BD patients also will exhibit other symptoms of mania during these mood cycling periods.