Abstract

This paper reviews some of the evidence indicating that hallucinogens or psychedelic substances have therapeutic effects. The general character hallucinogen use in non- Western societies is briefly reviewed to present data about the characteristic beliefs and uses associated with these substances. Evidence for therapeutic effectiveness is addressed from several perspectives: the findings from clinical medicine on effects of LSD; a general model of altered states of consciousness, their physiological characteristics, and therapeutic effects; and laboratory studies of physiological, sensory, emotional, behavioral, and cognitive effects of hallucinogens. These findings illuminate the general psychophysiological effects of hallucinogens and their consciousness altering and therapeutic mechanisms.