Electroencephalography while a child is in a mildly frustrating situation may improve distinction of pediatric bipolar disorder versus severe mood dysregulation syndrome, according to an article in the February issue of the American Journal of Psychiatry.

Results of the study, which was conducted by the US National Institute of Mental Health (NIMH), indicate that different brain mechanisms may lead to irritability in children with severe mood dysregulation than in children with bipolar disorder, a finding that may allow more effective diagnosis and treatment of both conditions.

"These aren't children with the occasional bad moods you see in most kids. They're typically very ill, with symptoms that interfere with their lives in major ways. Establishing clear diagnostic criteria is an essential step toward making sure they get the help they need," said NIMH Director Thomas R. Insel, MD.

Children have a comparatively low rate of bipolar disorder, but the rate increases with age to approximately 1 percent among adolescents. About 3 percent of pre-adolescent and adolescent youth are estimated to have severe mood dysregulation. Mood-stabilizing and antipsychotic medications are used to treat children with bipolar disorder, although data on effectiveness are limited and several studies are underway. Because severe mood dysregulation was only recently defined, there are no systematic studies on its treatment, and children are often treated as if they have bipolar disorder.

Defining pediatric bipolar disorder is a major issue in child psychiatry because it tends to be severe in this age group and the rate of diagnosed cases is rising. Until recent years, most studies of bipolar disorder were conducted in adults. Some researchers maintain that pediatric bipolar disorder should be defined more broadly to include children with severe mood dysregulation, an assertion countered by the new findings.

The classic definition of juvenile bipolar disorder includes extreme, sustained mood swings that range from over-excited, elated moods and irritability -- the manic phase of the disorder -- to depression. In contrast, children with severe mood dysregulation are extremely irritable and hyperactive but do not have clear-cut manic episodes.

One component of irritability is the tendency to get acutely frustrated when a goal is not met. Thus, researchers used electroencephalograms to observe brain activity when children with one disorder or the other were given a mildly frustrating simple task.

"We're approaching the day when we'll be able to use neuroscience techniques to improve psychiatric diagnoses. Pediatric bipolar disorder has some of the most pressing needs in this regard, because of its severity and because of questions about how to best make the diagnosis," said senior author Ellen Leibenluft, MD, Chief of the Unit on Bipolar Spectrum Disorders in the Emotion and Development Branch of the NIMH Mood and Anxiety Disorders Research Program.

In this study, scientists obtained electroencephalograms of 35 children with classic bipolar disorder, 21 children with severe mood dysregulation, and 26 healthy children (average age 12 to13 years) while they performed a task repeatedly; each time they did the task, they won or lost 10 cents. The task was frustrating because the children often lost money.

Although both groups of patients became more frustrated than healthy children performing the same task, the brain mechanisms associated with their frustration differed.

Children with bipolar disorder had an abnormality in the brain's P3 electrical signals, which measure ability to purposefully direct attention, whereas children with severe mood dysregulation had abnormalities in N1 signals, which occur when a stimulus grabs someone's attention. Both abnormalities suggest deficits in the brain's attention-related activity, but in different phases of that activity.

"If future research indicates that bipolar disorder and severe mood dysregulation are two separate disorders, this could guide parents and physicians toward the right treatments," said lead author Brendan Rich, PhD, of the NIMH Unit on Bipolar Spectrum Disorders. "A good example is that medication prescribed for symptoms seen in severe mood dysregulation, such as stimulant medication, might be inappropriate for a child with classically defined bipolar disorder."