BP-NOS Often Develops Into Bipolar I or II Disorder

November 4, 2011 · Posted in Course of Illness 

At a symposium on new research on juvenile bipolar disorder at the meeting of the American Academy of Child and Adolescent Psychiatry (AACAP) in 2010, David Axelson of the University of Pittsburgh summarized the longitudinal course of sub-syndromal bipolar disorder in children and adolescents as observed in a research program called COBY (Course and Outcome of Bipolar Youth). Axelson called attention to the 35% of the bipolar spectrum children who had a diagnosis of bipolar NOS (not otherwise specified) as opposed to the 58% who had full-blown bipolar I illness. BP-NOS is defined as illness not meeting criteria for bipolar I or II, including duration of illness and number of symptoms, so it includes presentations in which there is one fewer symptom present than the four required for a diagnosis of euphoric mania or the five required for a diagnosis of irritable mania. The mania or hypomania in BP-NOS must occur for at least four hours/day for at least four days.

young man

Overall, the COBY researchers found that among children with a BP-NOS diagnosis, it was the duration of the manic symptoms that tended to fall short of the requirements for a BP-I or BP-II diagnosis rather than any qualitative difference in clinical presentation. The COBY study followed 446 BP-NOS patients aged 7 to 17 for an average of five years using the LIFE methodology, which rates severity of ill states on a weekly basis. The assessments of LIFE data were conducted at an average of eight-month intervals.

Axelson’s key point was that within the 5-year period of the study, 45% of the children with BP-NOS, which some would consider a subthreshold bipolar disorder, converted to a full-blown bipolar disorder; 23% to a BP-I presentation and 22% to a BP-II presentation. If there was a positive family history of mania, it was even more likely that a child with BP-NOS would convert to BP-I or BP-II (58.5%, as opposed to 35.5% when there was no positive family history for mania).

Children with BP-NOS are almost as highly impaired as those with BP-I and BP-II illness, and clearly deserve early treatment intervention, both to alleviate problematic symptomatology, but also to possibly prevent the conversion to more full-blown BP-I and II syndromes. Axelson stressed the importance of treating those with BP-NOS who do not convert to BP I or II, because they too remain substantially impaired.


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