Thanks for the replies! Sounds like a sleep study may be worth a try. I've never thought of myself as being narcoleptic, and I don't think I meet the DSM criteria, but I am tired a lot. I've always linked that to my bipolar episodes, though, since I'm generally most fatigued during depressions and not during euthymia or hypomania. I wonder if it would be difficult to separate the sleep study results from symptoms of mood episodes?