Twenty-one paid volunteers who were chronic users of LSD were interviewed and participated in a series of cognitive and perceptual tests and EEG studies. Among other observations derived from both interviews and testing, the authors noted that the group shared a set of magical-mystical beliefs and profound nonaggressive attitudes, as well as a unique sensitivity to certain types of sensory stimulation. The authors suggest that the beliefs and attitudes of the group may have arisen as learned consequences of frequent, intense LSD experiences in susceptible individuals.Abstract Teaser