Defining clinical phenotypes of juvenile mania.

OBJECTIVE The authors suggest criteria for a range of narrow to broad phenotypes of bipolar disorder in children, differentiated according to the characteristics of the manic or hypomanic episodes, and present methods for validation of the criteria. METHOD Relevant literature describing bipolar disorder in both children and adults was reviewed critically, and the input of experts was sought. RESULTS Areas of controversy include whether the diagnosis of bipolar disorder should require clearly demarcated affective episodes and, if so, of what duration, and whether specific hallmark symptoms of mania should be required for the diagnosis. The authors suggest a phenotypic system of juvenile mania consisting of a narrow phenotype, two intermediate phenotypes, and a broad phenotype. The narrow phenotype is exhibited by patients who meet the full DSM-IV diagnostic criteria for hypomania or mania, including the duration criterion, and also have hallmark symptoms of elevated mood or grandiosity. The intermediate phenotypes include 1) hypomania or mania not otherwise specified, in which the patient has clear episodes and hallmark symptoms, but the episodes are between 1 and 3 days in duration, and 2) irritable hypomania or mania, in which the patient has demarcated episodes with irritable, but not elevated, mood. The broad phenotype is exhibited by patients who have a chronic, nonepisodic illness that does not include the hallmark symptoms of mania but shares with the narrower phenotypes the symptoms of severe irritability and hyperarousal. CONCLUSIONS The presence of distinct episodes and hallmark symptoms can be used to differentiate clinical phenotypes of juvenile mania. The utility and validity of this system can be tested in subsequent research.