On other forums, I've seen ENTPs talking about going several nights in a row without sleep because of what they described as "Ne function," psychic intuition, whatever, it's also called "racing thoughts" in the DSM and if you've stayed up 3 nights because of them, I'm gonna go head and say that the last 3 days have seen a remarkably different ENTP marauding around the house. That "Ne function" is hypomania well on its way to blowing up and showing the world a whole new you. Even Jungian literature about the MBTI remarks that ENTPs appear "hypomanic" when highly excited. Some of what I read on those forums could have come from the chapter on mood disorders in an abnormal psych class.
When I took the MBTI test in a psychiatric hospital, the first thing out of my mouth after reading the results was, "what's the rate of bipolar illness for this personality type?" They didn't know. But we know a few things about ENTP: the average IQ is well above expected, the rate of giftedness far exceeds the norm, and that swivel-chair psychologists on the Interwebz have squarely identified ENTP as the "sociopathic" type. I do not know about any unusual numbers of ENTPs receiving diagnoses of antisocial personality disorder, but that's because we're better at our jobs than the shrinks are at theirs. And the rate of manic-depressive illness among true ENTPs would astonish us all. Even the centrality of extraverted intuition reminds me of the manias I've had, the adventures and shenanigans and sin and madness of it; and of course all the poetry I have written while in a swing (I'm at the University of Iowa for poetry, I'm trying not to be a douche about poetry) and it's hard to think about. Manic depression is a gift and a curse. You get superpowers- oh yes, mania makes all the Jungian functions look childish- and you will suffer. Greatly.
But really, I don't accept for a moment the notion that there is a bipolar "disease" and I am not wearing a giant foam mitt advertising the term "disorder" either. "Illness" works because it allows there to be wellness. But I prefer "difference;" we know that manic depression is a genetic phenomenon, and its existence was recorded by the ancient Greeks.
A society needs a slice of manic-depressives or there can be no art and no music and no sunlight because we're probably talking about Alaska. It's a cold world, espeially when youre bipolar, but it's good to remember that it's been passed down to you and it's your gift and your curse.