It's quite another to think you have bipolar disorder but really you were misdiagnosed. There is a spike in reported cases, and it's coming to light that many times that's a result of misdiagnosis.
"From 1993-2004, the diagnosis of bipolar disorder in children increased by 40 fold (Moreno, et al 2007
The extent misdiagnosis happens is up to wild debate. But that doesn't 'stop more and more studies from coming out, and stats being released, to confirm there's an upward trend.