A former boss of mine suffered with this illness for years before he was finally definitively diagnosed a few years ago. Doctors had treated him for depression, but that was only part of it. He self-medicated with alcohol for a long time and that may have been why doctors didn't really know what was wrong with him. Last I heard he was involved in a study on bipolar disorder at the University of Pittsburgh. Not sure if anything came out of the study or if it's still ongoing.
I hope he has found some relief. He was a brilliant trial attorney, then everything fell apart for him. His legal career sunk like a rock. Kicked out of three law firms. In between, his beloved wife developed cancer and passed away. Two of his three kids were losers and no help at all. Tragic.