J.K. Rowling

The 'Harry Potter' author suffered from depression in her 20s and says that it is impossible to describe to a person who have not experience the condition.

In an interview with Oprah Winfrey, Rowling said: "It's so difficult to describe [depression] to someone who's never been there, because it's not sadness. But it's that cold absence of feeling - that really hollowed-out feeling."