It has been noted that there seems to be a correlation between mood disorders and creativity. Many great artists, poets, writers, musicians have been troubled with mental health issues.: Ernest Hemingway, Carrie Fisher, Kurt Cobain, to name a few.
Jim Phelps, M.D. writes on his website how some evolutionary biologists believe that there is an advantage to having a small dose of bipolar genes (similar to having a trait), advantages like: creativity, courage, productivity. 1 The idea of having a bipolar trait is one theory.