Lizzie (1957)

Elizabeth has reoccurring headaches and trouble sleeping. Threatening letters signed by Lizzie are given to her, but she does not know anyone named Lizzie. As her situation deteriorates, she goes to a Dr. Wright who hypnotizes her. Deep in her subconscious, Dr. Wright finds three personalities; Elizabeth, the shy one that everyone knows; Lizzie, the wild one like her mother; and Beth, the good one she should have become. Dr. Wright must help the personality of Beth become the only one.