Kay Redfield Jamison

Her parents, she said, has put a pinball machine inside her head when she was five years old. The red balls told her when she should laugh, the blue ones when she should be silent and keep away from other people; the green balls told her that she should start multiplying by three. Every few days a silver ball would make its way through the pins of the machine. At this point her head turned and she stared at me; I assumed she was checking to see if I was still listening. I was, of course. How could one not? The whole thing was bizarre but riveting. I asked her, What does the silver ball mean? She looked at me intently, and then everything went dead in her eyes. She stared off into space, caught up in some internal world. I never found out what the silver ball meant.
-Kay Redfield Jamison, An Unquiet Mind: A Memoir of Moods and Madness