Can stress really cause your hair to turn white or grey? If so, why does it do that?

The Maelstrom. Edgar allan poe described the fisherman caught in the maelstrom with premature white hair. No one really believes that this is true. Pigment of the hair gradually fades with age. Disease and genetics (albinism) can alter the pigment cells, but the effect is slow and specific to those hairs that lack the pigment.