From the 1960s to the present day, American research into the therapeutic effects of psychedelic drugs has focused on their ability to facilitate “mystical” experiences in test subjects. “Mysticomimetic” research has close ties to perennialist notions of religion that gained popularity over the course of the 20^th century. Figures such as William James and Aldous Huxley promoted perennialist ideals within intellectual circles, particularly influencing psychological researchers. As research into psychedelics has gathered momentum from the 2000s onward, claims that mystical experience is key to the compounds’ palliative effects remain tied to perennialist thought, with current research picking up where studies in the 1960s left off. Perennialism can itself be considered a new religious movement that has developed in scientific and academic circles, the existence of which brings into relief the breakdown of notions of a dichotomist relationship between science and religion in the process.