yea 1% in the UK
Bipolar Disorder (manic depression)
This is the page from the Royal Collage of Psyciatrists, so I'd say a good source for a statistic.
Teeny tiny. I do think that in the US they tend to be diagnosis happy....
I had a bit of a though earlier in the week... if there is a larger population of obese/sluggish people, normal/energetic beahviour must seem hyper... may be why there seems to be over diagnoses of hyperactivity... sorry I may be clouding thoughts here