Shirley Ardell Mason, formerly known as Sybil Isabel Dorsett, has dissociative identity disorder. The movie about her, The case on Sybil goes over her story and is a visual representation on the book by her own psychologist, Doctor Wilbur.

In the beginning of the movie, Sybil shows some vulnerability to her triggers such as a squeaking swing and a piano playing loudly. Sybil starts showing very odd behaviors such as holding her breath, breaking the glass out of window panes, and constantly looks at her watch, as if she was an entirely different person. She has “blackouts” between these shifting of behaviors that tend to last a few hours but can last up to years. The picture that Sybil is afraid of, is a picture of her mother, whom she is terrified