Sleep and dream research are truly foundational to psychiatry, and history reflects how psychiatry has struggled to come to terms with mind versus brain dualism. Stimulated by speculative dynamic neurologists like Pierre Janet and Jean-Marie Charcot, Sigmund Freud created psychoanalysis in the same period Kraepelin and Bleuler labored. Of central importance to Freud's theory was his view of dreaming as an unconsciousmental process by which dreamers could bowdlerize unacceptable unconscious wishes that threatened to invade consciousness and awaken them. By preventing subjects from entering REM with enforced awakenings, William Dement and Charles Fisher theorized they could prevent dreaming and thus cause psychological distress in their subjects. By the mid-1970s, experimental dream laboratories were failing, but modern sleep medicine was burgeoning. As the reciprocal interaction and activation-synthesis hypotheses evolved, they metamorphosed into the 'activation level, input source, and mode of processing' (AIM) model based on findings in sleep and dream research. sleep medicine, psychiatry, REM sleep, dream deprivation, AIM model, dream consciousness