How Do Psychedelics Reduce Fear of Death?

Increasing evidence suggests that psychedelic experiences, undergone in controlled conditions, can have various durable psychological benefits. One such benefit is reductions in fear of death, which have been attested in both psychiatric patients and healthy people. This paper addresses the question: how, exactly, do psychedelic experiences reduce fear of death? It argues, against some prominent proposals, that they do so mainly by promoting non-physicalist metaphysical beliefs. This conclusion has implications for two broader debates: one about the mechanisms of psychedelic therapy, and one about the potential non-medical uses of psychedelics for the alleviation of existential angst in psychiatrically healthy people. On the first count, the paper argues that the role of metaphysical belief change in fear of death supports the “Relaxed Beliefs Under Psychedelics” (REBUS) model of psychedelic therapy over alternative accounts. On the second count, the paper argues that the role of metaphysical belief change undermines the proposed use of psychedelics in the “neuroexistentialist” project of naturalizing spirituality. The best available evidence suggests that when psychedelic experiences reduce existential angst and restore a sense of meaning in life, they do so primarily by persuading people of the falsity of a broadly naturalistic worldview, and thus do not help reconcile people to the truth of such a worldview.