Also see: The Source Code of Creativity: How Flow Drives Creative Genius

From The Rise of Superman via YouTube:

Flow is a powerful force for human achievement, but flow states also hide a dark side. The neurochemicals underpinning flow have all the addictive power of drugs, and the drive to achieve these seemingly super-human feats sometimes brings athletes face to face with their limits.

Episode 4 of The Rise of Superman video series explores how far people will go to achieve ultimate human performance, and the potential downsides of that pursuit. Jimmy Chin, Travis Rice, Dean Potter, Mike Horn, Danny Way and Robbie Maddison talk candidly about moments in their lives when the pushing the limits of their own capabilities brought them perilously close to the edge.