Canada

The roots of psychedelic research that affected Canada begin with discoveries in Europe: lysergic acid diethylamide (LSD) was synthesised by Albert Hofmann at Sandoz (Basel) in 1938 and its psychoactive properties were described in 1943. From the late 1940s Sandoz marketed LSD under the trade name Delysid and distributed material to researchers and psychiatrists internationally; Canadian clinicians and investigators were among those who received early supplies for experimental and therapeutic work. This international supply chain shaped the early clinical and psychiatric experimentation with serotonergic compounds in Canada during the 1950s and 1960s.

Within Canada the 1950s saw some of the most visible early clinical work. Notably, psychiatrist Humphry Osmond and colleague Abram Hoffer at Weyburn Mental Hospital in Saskatchewan conducted systematic studies of LSD and mescaline, particularly for alcoholism and related disorders. Osmond coined the term "psychedelic" in correspondence during this era; the Saskatchewan work became a reference point for later debates about therapeutic potential, methodology and ethics. Other Canadian clinicians experimented with psychedelics within psychiatric settings, often publishing case series and mechanistic speculation common to the period.

The cultural and regulatory backlash of the late 1960s and early 1970s, driven by widespread recreational use and international drug control agreements, brought a steep curtailment of clinical work. At the federal level, psychedelics were criminalised and tightly controlled under Canadian narcotics and subsequent Controlled Drugs and Substances frameworks, meaning that research required formal approvals, licences and stringent oversight. This regulatory environment, combined with reduced supply and shifting funding priorities, produced a multi-decade lull in mainstream clinical research.

Since the late 1990s and especially over the past decade there has been a marked revival of scientific and clinical interest in psychedelic compounds. Canadian investigators, hospitals and universities have re‑engaged with clinical trials and mechanistic studies, while a parallel ecosystem of advocacy groups, private companies and patient organisations has pushed for compassionate access and regulatory adaptation. Health Canada has granted case‑by‑case exemptions for therapeutic use in recent years and permitted carefully regulated research and training activities, signalling a changed but cautious posture compared with mid‑20th century practice.