The nature of the shamanic state of consciousness: a review.

A review of the literature suggests that a common psychobiological process is associated with various altered states of consciousness (ASC) utilized by shamans, meditators, and mediums. However, the shamanic state of consciousness (SSC) can be differentiated physiologically from possession trance states. The psychophysiological literature on different types of trances and on seizure conditions associated with the temporal lobe discharge syndrome is reviewed. On this basis, it is hypothesized that while both the SSC and possession trances involve hippocampal-septal stimulation, the difference between the SSC and the possession states includes the amygdala involvement associated with the latter. This criterion and others establish a basis for differentiating between the terms "shamanic," "shamanistic," and "mediumistic." The physiological concomitants of the SSC make it appear to be both physiologically and psychologically beneficial as well as indicating that it is most likely that there is a genetic component affecting one's ability to enter the SSC and other ASC.