Is psychedelic use associated with cancer?: Interrogating a half-century-old claim using contemporary population-level data.

BACKGROUND: In 1967, concerns about the carcinogenic potential of psychedelics arose after a study reported chromosomal damage in human leukocytes following in vitro lysergic acid (LSD) exposure. Worries were further heightened by subsequent reports of leukemia and other cancers in LSD users. Additional investigations of psychedelics' effects on chromosomes were published over the next decade, with the majority suggesting these concerns were unfounded. However, the relationship between psychedelics and cancer has been explored only minimally from an epidemiological perspective. AIMS: To determine whether associations exist between psychedelic use and either lifetime cancer or hematologic cancer diagnoses. METHODS: We analyzed data from adult participants in the 2015-2019 administrations of the National Survey on Drug Use and Health for associations between lifetime use of psychedelics and lifetime diagnosis of either any cancer or hematologic cancer. RESULTS: We identified no associations between lifetime psychedelic use and either lifetime cancer diagnosis or hematologic cancer diagnosis. Sub-analyses of lifetime lysergamide, phenethylamine, and tryptamine use also revealed no associations with lifetime cancer or hematologic cancer diagnosis. CONCLUSIONS: While laboratory studies and case reports from the 1960s and 1970s generated concerns about psychedelics' carcinogenic potential, this analysis of recent epidemiological data does not support an association between psychedelic use and development of cancer in general or hematologic cancer. Important study limitations to consider include a lack of information about psychedelic dosage, number of lifetime psychedelic exposures, and the temporal relationship between psychedelic use and cancer diagnosis.