This is the cover story of the New York Times Magazine for September 14. You'll find harrowing stories about kids with this mysterious disorder, pediatric bipolar disorder. Here's a portion of the article:
"The most basic question about bipolar kids remains a mystery:
Will they grow up to be bipolar adults? Because diagnosing the
condition in children is still relatively new, no studies have yet
followed a large number of them fully into adulthood. One fact is
suggestive: bipolar kids are predominantly male, while the adult
bipolar population skews slightly toward the female. The likelihood is
that many of these kids will grow up to have mental-health issues of
some kind, but which issues, and how chronic or severe they will be, no
one really knows. A long-term study in Pittsburgh overseen by Axelson
and Birmaher suggests that as children grow, the severity of their
disorders can change; bipolar II, the less severe form of the disease,
can convert to bipolar I, the more severe form. Nearly a third of
subthreshold bipolar cases (BP-N.O.S., or Not Otherwise Specified, in
D.S.M.) convert to the more serious forms."
Author Jennifer Egan goes on to quote another expert who notes that some kids seem to recover, leaving questions about what exactly was wrong when they were younger. Fascinating.