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David Hammond

School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.

1 paper in the library · 1 citation · publishing 2026

Papers

A cross-national comparison of nonmedical and medical use of psychedelic drugs in the international cannabis policy study.

The International journal on drug policy August 1, 2026 Myfanwy Graham, Yimin Ge, Rosalie Liccardo Pacula et al. 1 citation

An estimated 19% of adults in Canada, the United States, Australia, and New Zealand have used psilocybin, LSD, MDMA, or ketamine at some point in their lives. Psilocybin was the most commonly used substance, with lifetime use highest in Canada (16.3%), followed by the US (13.0%) and New Zealand (12.1%), and lowest in Australia (7.8%). Among those who had ever used a psychedelic, 10-20% had asked their medical provider about medical use, and over a third of past-year users reported experiencing an adverse health effect. Past-month use was low across all countries. Consumer interest in therapeutic use has outpaced clinical trials and therapeutic provisions, and many people use these substances outside regulated pathways, which may increase the risk of adverse events.