PARAGRAPH: Consciousness, for the purposes of this discussion, refers to an individuals awareness of their own thoughts, actions, environments and memories. Altered states of consciousness have been defined by Tart 1972 as 'a qualitative alteration in the overall pattern of mental functioning, such that the experiencer feels his or her consciousness is radically different from the way it functions ordinarily. this essay discusses the similarities and differences between the use of drugs, and dream states as altered states, although there are a number of altered states of consciousness. Dreams are most common in REM sleep, part of a four stage cycle that takes around ninety minutes to complete. In REM sleep, dreams are more visual, and there is stronger activation of emotion areas, and diminished activation of the frontal lobes (Nir & Tononi, 2010). There are a much wider range of substances that are under the classification of drugs, however, which can have a range of effects on a persons conscious perception. Psychedelic drugs like Psilocybin will be the focus of this discussion, comparing similarities in memory, methodological issues, and lack of inhibitions between dreams and drug induced states. It also discusses the neurological, ego and memory differences between the two.