View full lesson: http://ed.ted.com/lessons/the-mystery-of-chronic-pain-elliot-krane We think of pain as a symptom, but there are cases where the nervous system develops feedback loops and pain becomes a terrifying disease in itself. Starting with the story of a girl whose sprained wrist turned into a nightmare, Elliot Krane talks about the complex mystery of chronic pain and reviews the facts we're just learning about how it works and how to treat it. Talk by Elliot Krane.