I wouldn't say that bipolar individuals are more intelligent - smarter perhaps but not necessarily more intelligent. Intelligence incidentally is a measure of cognitive capacity. Smartness is experiential knowledge. I suggest that bipolar people tend to be more adept at gathering and recalling different knowledge. We have a thirst for expanding our world (to my understanding).

Creativity too I think goes hand in hand with this. It is no great leap to say that creativity and bipolar go hand in hand. Creativity itself takes a certain kind of smartness. And creativity takes multiple forms. While for some it may be the visual or performing arts, creativity also takes the form of elevated thought processes. Again, I don't believe a creative person is necessarily more intelligent but I DO think that they are able to use that intelligence in more creative ways. Thus, a bipolar person might seem to be more intelligent.