I love stories about hoaxes, so I will have to get the new book called Sybil Exposed, which goes behind the story of a woman allegedly afflicted with 16 different personalities. The sensational story generated an industry of sorts, including movies. Unfortunately, the story was total bullshit.
It seems the author of the original story was used by the so-called patient and her unethical shrink to generate publicity and money.
Adaptation of book
All three women are now dead, but the hoax lives on.
I read the book, Sybil, decades ago when it first came out. It doesn't surprise me at all the story was a fake.