Does our hair turn white all of a sudden?

Some historians write that \*\*Queen Marie Antoinette\*\*'s hair turned completely white on the night before she was due to go to the guillotine. Doctors admit that such an event can only occur in a matter of weeks in certain cases. Due to extreme grief or fear, a person's black hair can fall out en masse within a few weeks, leaving only the hair that had already turned gray or white. This condition can be seen in cases of diabetes, thyroid gland disorders, and extreme stress.