altered state of consciousness (ASC)
a state of psychological functioning that is significantly different from that experienced in ordinary states of consciousness. Reports of the experience of ASCs are highly subjective, but the phenomenon is susceptible to some degree of empirical study. It tends to be characterized by altered levels of self-awareness, affect, reality testing, orientation to time and place, wakefulness, responsiveness to external stimuli, or memorability, or by a sense of ecstasy, boundlessness, or unity with the universe. ASCs may result from changes in neurobiological functioning due to oxygen depletion or psychoactive drug use; from hypnosis, meditation, and sensory deprivation; or from mystical or religious experience. Although classical psychoanalysis has tended to regard ASCs as symptoms of regressive states, other schools of thought, such as Jungian, humanistic, and transpersonal psychology, regard them as higher states of consciousness and, often, as indicative of a more profound level of personal and spiritual evolution.