The long story
Twelve thousand years together.
One century apart.
People have grown cannabis for about as long as they have grown anything. It gave rope, cloth, food and oil long before anyone wrote laws, and it travelled with farmers, traders and healers across Asia, Africa, Europe and the Americas.
The connection runs deeper than farming. Every human body has an endocannabinoid system: a network of receptors and home-made signalling molecules that helps regulate mood, appetite, pain, memory and sleep. It evolved for the body's own chemistry, hundreds of millions of years before the plant existed — but the plant's compounds happen to fit the same receptors. That is why cannabis affects us at all.
Against that history, prohibition is new. The worldwide ban is barely a lifetime old, and this index measures how much of it is still standing.
- c. 10,000 BCE
Domesticated in East Asia
Genome studies trace all of today's hemp and drug varieties back to plants first cultivated in early Neolithic East Asia — making cannabis one of humanity's oldest crops, grown for fibre, seed and oil.
- c. 500 BCE
Smoked in the Pamir mountains
Wooden braziers from a 2,500-year-old cemetery in western China still carry residue of high-THC cannabis — the earliest direct chemical evidence of people using it for its effect on the mind.
- 1961
Banned by treaty
The UN Single Convention on Narcotic Drugs places cannabis in its strictest category, alongside heroin. Most national prohibitions date from this century, not earlier.
- 1964 – 1992
The body's own cannabinoids
Chemists in Israel isolate THC in 1964. Researchers then find receptors for it in the brain and, in 1992, a molecule the body makes itself to fit them. They name it anandamide, from the Sanskrit for bliss.
- 2013
The first country legalises
Uruguay becomes the first nation to make cannabis legal for adults. A handful of others have followed.
- 2020
The UN steps back
After 59 years, a UN commission votes 27 to 25 to remove cannabis from the treaty's most restrictive schedule, recognising its medical use.
Sources:Ren et al. 2021, Science Advances — domestication history of Cannabis sativa · Ren et al. 2019, Science Advances — the origins of cannabis smoking in the Pamirs · Gaoni & Mechoulam 1964, J. Am. Chem. Soc. — isolation of THC · Devane et al. 1992, Science — discovery of anandamide · UN News, December 2020 — UN commission reclassifies cannabis