Marie Antoinette syndrome

Marie Antoinette syndrome is an alleged condition of hair suddenly turning white. The name comes from folklore about the hair of Queen Marie Antoinette of France turning stark white after her capture following the ill-fated flight to Varennes during the French Revolution. According to the Federation of American Societies for Experimental Biology (FASEB), witnesses claimed that Antoinette's hair rapidly turned white on three occasions.
An example of this syndrome, albeit fictional, is from the Tokyo Ghoul manga, where the protagonist Ken Kaneki’s hair turns white after being tortured for ten days. It has been found that some hairs can become colored again when stress is reduced.
Causes.
The syndrome has been hypothesized to be a variant of alopecia areata diffusa or autoimmune non-scarring hair loss that selectively affects all pigmented hairs, leaving only the white hair behind. Marie Antoinette syndrome is caused by high levels of emotional stress, which, in turn, causes less pigmentation of the hair. These form the basis of most uses of the idea in fictional works.
One study (which requires scientific replication and verification) experimented with the phenomenon in mice found that stress caused white hair even if the immune system was suppressed (ruling out auto-immune response) and if the glands producing cortisol were removed. The study concluded that over-activation of the sympathetic nervous system was causing stem cells to stop producing pigment cells in hair follicles.
History.
The earliest surviving recorded claim of sudden whitening of the hair is represented in the Talmud, by a story of a Jewish scholar who, at the age of 17 years, developed white hair locks due to overwork.
Now and again, contemporary cases of accelerated (though not sudden) hair-whitening have been documented, as with bombing victims in the Second World War, and in a case covered in the medical journal "Archives of Dermatology" in 2009.