Recovery of memory after posthypnotic amnesia.

Documentation of the reversibility of posthypnotic amnesia has been hampered by the correlation of hypnotizability with the initial level of response to amnesia suggestions. In a sample of 691 subjects, groups differing in hypnotic susceptibility could be matched for initial amnesia recall, thereby eliminating the ceiling effect. At virtually every point along the distribution of initial amnesia response, hypnotizable subjects were significantly better able than insusceptible subjects to recapture the previously blocked memories after the amnesia suggestion was lifted. Conversely, those subjects who showed reversibility of amnesia were more responsive overall to hypnosis than those who did not. Reversibility is of value in distinguishing between amnesia and pseudoamnesia and between partial amnesia and nonamnesia. Furthermore, reversibility helps define posthypnotic amnesia as a process involving the disruption of retrieval processes in memory.