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.
http://www.ted.com/talks/elliot_krane_the_mystery_of_chronic_pain.html
