Her case was depicted in the 1950s book The Three Faces of Eve, written by her psychiatrists, Corbett H. Thigpen and Hervey M. Cleckley, upon which the film of the same name, starring Joanne Woodward, was based.
In accordance with then-current modes of thought on the disorder, Thigpen reported that Sizemore had developed multiple personalities as a result of her witnessing two deaths and a horrifying accident within three months as a small child.
However, in Sizemore's own report, these traumatic incidents only triggered the evidencing of selves which were already present: Despite authorities' claims to the contrary, my former alters were not fragments of my birth personality.
[citation needed] In 1970, she started treatment with Tony Tsitos, whom she credited with making the greatest progress in integrating the divergent personalities over the next four years.
[4] According to both Sizemore and the psychiatrists who worked with her after her treatment with Thigpen and Cleckley, it was not until she was in Tsitos' care that she became aware that she experienced not just 3 selves but more than 20 personalities, that eventually were unified.
Upon discovering in 1988 that her legal rights to her own life story had been signed away to 20th Century Fox by Thigpen, Sizemore went to Manhattan's Federal District Court to contest the contract.