In short: psychedelics were studied intensively in the 1950s and 60s, including in Saskatchewan, before laws in the early 1970s all but stopped the research. A revival that began in the 1990s and 2000s has produced today’s clinical trials. Along the way, plenty of myths built up on both sides.
A short history
- Traditional use. Psilocybin mushrooms, peyote, ayahuasca and iboga have been used in Indigenous ceremonial and healing traditions for centuries or longer.
- 1938–1943: LSD. Swiss chemist Albert Hofmann first made LSD in 1938 and discovered its effects in 1943.
- 1950s: Saskatchewan. At the hospital in Weyburn, psychiatrists Humphry Osmond and Abram Hoffer studied LSD as a treatment for alcoholism. Osmond coined the word “psychedelic” in 1957.
- 1958: psilocybin. Hofmann isolated psilocybin from mushrooms.
- 1960s: research and backlash. Thousands of research papers were published, but loose methods and rising recreational use led to a political backlash.
- 1970–1971: prohibition. The US Controlled Substances Act (1970) and the UN Convention on Psychotropic Substances (1971) put most psychedelics in the most restricted categories. Research all but stopped for two decades.
- 1990s–2000s: revival. Researchers restarted human studies, including DMT studies in the 1990s and a 2006 Johns Hopkins study of psilocybin in healthy volunteers.1
- 2000: ketamine for depression. The first controlled study showed rapid antidepressant effects.
- 2019–2020: esketamine approved in the US and Canada.
- 2020s: larger trials of psilocybin and MDMA, new regulations in Alberta, Oregon and Australia, and a US regulatory setback for MDMA in 2024.
Common myths, checked against the evidence
“Psychedelics are highly addictive.” Mostly false for classic psychedelics. Psilocybin, LSD and similar drugs have low potential for dependence, and tolerance builds quickly, which discourages frequent use. Ketamine is different: it can be habit-forming, and MDMA carries some risk of problematic use.
“One psychedelic trip will fix depression.” False. Some people improve after one or two sessions in trials, but not everyone responds, benefits can fade, and trials include preparation, support and follow-up. It’s a treatment approach, not a switch.
“Microdosing is proven to work.” Not supported yet. In a large self-blinded study, people microdosing reported improvements, but so did people unknowingly taking placebo, and the differences between them were small.2 Better-controlled trials are under way.
“Natural means safe.” False. Ayahuasca can interact dangerously with common antidepressants, and ibogaine, from a plant, can cause fatal heart-rhythm problems. See Safety.
“Psychedelics will make you go crazy.” Misleading. In screened, supervised trials, lasting psychiatric harm is rare. But psychedelics can trigger psychosis or mania in vulnerable people, which is why trials exclude people with those histories.
“Ketamine is just a horse tranquilizer.” Misleading. It’s used in veterinary medicine, but it was developed for people and is on the WHO’s List of Essential Medicines. See our ketamine guide.
“The science is settled.” Not yet. There are promising results, some approved treatments, and many open questions about blinding, long-term effects and who benefits most. That’s why we grade the evidence (see What the evidence says).