The phrase altered state of consciousness, coined in the 1970s, describes intentionally induced changes in one's mental state, sometimes attained through the ingestion of drugs and psychedelic substances such as LSD, peyote, marijuana, mescaline, and the like.

An altered state of consciousness can also come about through the use of alcohol, a sensory deprivation tank, hypnosis, meditation and the practice of certain rituals (e.g. prayer) and disciplines (e.g. yoga).

Naturally occurring altered states of consciousness include channeling, dreams, premonitions, euphoria, and limerence.

Also see