After Sybil’s suicide attempt, Dr. Wilbur reluctantly decides to treat Sybil with sodium pentothal, a barbiturate sometimes used as anesthetic that can also calm anxiety and induce drowsiness, which was used, according to Schreiber, as a hypnotic. Using pentothal in combination with psychoanalysis, she hoped, would make it possible for Sybil to tolerate the pain associated with recalling and discharging her still-buried trauma.

The effects of pentothal last 56 to 70 hours, and give Sybil a sense of complete freedom and wellness, a feeling she’s never had before. On the days after the treatment, having discharged some of her traumatic memories while “asleep,” under the influence of pentothal, she feels euphoria. Dr. Wilbur then presents Sybil with the memories that poured out of her while she was “asleep,” and they begin to filter into her normal awareness. The most powerful feeling unleashed by the pentothal is a deep-seated hatred of her mother.

Though the pain of the memories sometimes provokes even more regression into other personalities, glimmers of integration begin to show during treatment with sodium pentothal. One Friday night, in the spring of 1958, Sybil, thinking about the previous day, which was blank to her, suddenly remembers what happened. The sensation is odd: she doesn’t remember what she did as Sybil, but what she “had done as Mary and Sybil Ann” (371).