We tend to think that the great figures of history—those who changed the world through their inventions or art or books—were free of the kind of self-doubts and neuroses that can hold back the rest of us. But as Claudia Kalb discovered when researching Andy Warhol Was a Hoarder: Inside the Minds of History’s Great Personalities (published by National Geographic), famous people also can suffer from chronic psychological or physiological disorders, which deeply affect their lives and the lives of those around them. New advances in neurological science are now enabling us to better understand their challenges—and our own. (Find out why your brain is hardwired to snap.)

Talking from her home in Alexandria, Virginia, Kalb takes us inside