White Hair...

[outside artist]

I recently read a factual book in which someone underwent such trauma that his hair turned completely white overnight. I have heard of this, but I never believed it actually happened. What exactly causes this, biochemically speaking, that is?

[Shagnasty]

It doesn't. Well sort of.

http://www.straightdope.com/classics/a2_315b.html

[outside artist]

Oh, silly of me to not have checked Cece first, but thank you.
This makes me wonder about the veracity of the rest of the volume.