I recently read an article, In the article it stated that one doesn't have to experience the highs to have bipolar. There are a few well respected doctor's who back this theory. They believe that there is another form of bipolar in which you only experience the lows. I don't think there has been any definitive research done on this, Therefor i can't agree with it. Try doing a little research and see what you come up with.

Good luck!