Mental health seems to be all the rage in the corporate world today. But the reality is that great leaders, great creatives, and great innovators throughout time have also been likely to suffer from bouts of mental strain and illness - even if it was called something else. Historian Nancy Koehn has long studied leaders from Abraham Lincoln to Oprah Winfrey, and she shares lessons from them on how to get through depressive or anxious times - lessons she’s even applied in her own life.