A note of caution on the Waterloo-Stanford Group Scale of hypnotic susceptibility: a brief communication.

The scant literature on the sequelae of hypnotizability-measurement instruments indicates that different scales produce different reactions. The Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C (WSGC) was developed as a group version of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). Parallel to the literature showing that the SHSS:C can produce more negative aftereffects than the Harvard Group Scale of Hypnotic Susceptibility, Form A, we report preliminary descriptive statistics documenting the infrequent occurrence of negative reactions to the WSGC age-regression item. We recommend that experimenters take this matter into consideration and, at the very least, ensure the presence of a clinician with hypnotic experience during the administration of the WSGC.