...that manic depression, far from being a liability was an advantage. It was a selected trait. If it wasn't selected for, then the "disorder" would have disappeared long ago, bred out of the population like anything else that didn't increase the odds of survival. The advantage was obvious. The advantage was the energy, the creativity, the feeling of genius, almost, that Leonard felt right now. There was no telling how many great historical figures had been manic-depressives, how many scientific and artistic breakthroughs had occurred to people during manic episodes.

Autore: Jeffrey Eugenides