When she was 9 years old, Camilla would entertain her friends by jumping off her bed and landing directly on her knees. She said she liked to hear the crunching sound they made—just like popcorn.
Another time, Camilla spent an entire school recess period walking around on a broken leg, without so much as a whimper, says neuroscientist India Morrison of the University of Gothenburg in Sweden. The child’s teachers didn’t believe Camilla when she said something was wrong, because she wasn’t sobbing or wailing in pain. Her father thought perhaps her leg needed massaging, but quickly realized the situation was much worse.
