Samuel Donkoh had just turned ten when he began to slip away. His brother Martin, two years his senior, first realized something was wrong during a game of soccer with a group of kids from the neighborhood. One minute Samuel was fine, dribbling the ball, and the next he was doubled over in spasms of laughter, as if reacting to a joke nobody else had heard. His teammates, baffled by the bizarre display, chuckled along with him, a response Samuel took for mockery. He grew threatening and belligerent, and Martin was forced to drag him home.