Viewpoint: COBY Study of Children With Bipolar Disorder Provides Important Longitudinal Descriptive Information




Randall F. White, MD, FRCPC; Andro Giorgadze, MD

Medscape Psychiatry & Mental Health. 2006;11(1) ©2006 Medscape
Posted 03/29/2006
Clinical Course of Children and Adolescents With Bipolar Spectrum Disorders

Birmaher B, Axelson D, Strober M, et al
Arch Gen Psychiatry. 2006;63:175-181
Summary

This is the first report from the Course and Outcome of Bipolar Illness in Youth (COBY) study, a multisite, prospective investigation of children aged 7 to 18 years with bipolar I and II disorders and bipolar disorder not otherwise specified (NOS). The investigators used stricter criteria than those in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), for bipolar disorder NOS: mood change and at least 2 other manic symptoms lasting 4 hours during at least 4 not-necessarily consecutive days. They recruited subjects from inpatient and outpatient settings in 3 US urban areas, verified diagnoses using the Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version (K-SADS-PL), and documented the longitudinal course of psychiatric symptoms of 263 children during a mean period of 95 weeks.

The report provides data on recovery from the most recent mood-disorder episode, recurrence of disorder, changes in mood polarity, and conversion from 1 type of bipolar disorder to another. Overall, 68% of subjects recovered from the index episode in a mean of 78 weeks; those with bipolar disorder NOS required a mean of 140 weeks, significantly longer than those with other types. Factors associated with lower likelihood of recovery included earlier onset of disorder, prepubertal status, lower socioeconomic status (SES), and bipolar NOS diagnosis. That diagnosis, however, was associated with a lower risk of recurrence than bipolar I or II diagnoses, the mean rate of which was 56% in the whole cohort. More than half of recurrences were depressive episodes, whereas 14% were manic. On average, subjects spent 22.4% of the observation time in syndromal mood episodes, 38% in subsyndromal mood episodes, and 3.1% with psychosis.

SES was inversely related to risk of recurrence and to total duration of mood symptoms. The presence of psychosis was associated with chronic mood symptoms, and along with low SES and bipolar NOS diagnosis, predicted more annual changes of mood polarity. Approximately 20% of subjects with either bipolar disorder NOS or bipolar II disorder converted to bipolar I disorder during the course of observation.
Viewpoint

This report confirms that bipolar disorder is fluctuating and recurrent in many patients early in its course. Worse outcomes occur with low SES, early onset, and psychosis. Low SES is a marker of many potential risk factors, including medical illness, unstable housing, poor nutrition, and prenatal stress; further investigation is necessary to determine the factors contributing to worse outcome in bipolar disorder. Bipolar NOS, as defined by these investigators, has a distinct profile, but during this relatively brief observation, 25% of cases converted to bipolar I or II disorder. The significance of the diagnosis as an entity is uncertain; perhaps it is a prodrome.

As in most prospective studies, selection bias is a concern, especially because the subjects were drawn from clinic populations; hence, the findings may not reflect the general population of patients with bipolar-spectrum disorders. Nevertheless, this well-conducted cohort study, the largest of bipolar youth to date, will yield many more findings.



Randall F. White, MD, FRCPC, Psychiatrist, St. Paul's Hospital, Vancouver, British Columbia

Andro Giorgadze, MD, Emory University, Atlanta, Georgia

Disclosure: Randall F. White, MD, has disclosed that he owns stock, stock options, or bonds in Novartis AG ADR, Millipore Corp., Novo Nordisk, and sanofi-aventis.

Disclosure: Andro Giorgadze, MD, has disclosed no relevant financial relationships.