25,000-Year-Old Teeth Push Back Timeline for Earliest Habitual Psychoactive Drug Use

On September 9, 2026, researchers from Australia and Indonesia published findings in the journal Science Advances revealing that human drug use dates back at least 25,000 years—tens of thousands of years earlier than previously established. The study centers on the skeletal remains of two prehistoric hunter-gatherers unearthed on the Indonesian island of Sulawesi, whose teeth bear deep, rounded grooves from habitually sucking on whole betel nuts.[1]

The discovery upends the long-held archaeological consensus that the habitual consumption of psychoactive substances began alongside the agricultural revolution roughly 12,500 years ago. Prior to this finding, the earliest evidence of drug use was tied to the Neolithic production of fermented alcoholic drinks, such as barley beer in Israel, and the cultivation of specific crops for their mind-altering properties.

The two adult foragers examined in the study lived millennia apart, yet shared the same distinct dental pathology. The older individual, a man who died between the ages of 40 and 50, was recovered from the Leang Bulu Bettue site and lived between 25,000 and 16,000 years ago during the Last Glacial Maximum. The second individual, found at the Leang Cappalombo 1 cave, lived between 7,600 and 6,300 years ago.[1]

Both sets of remains exhibited a highly unusual pattern of dental wear that initially puzzled the excavation teams. The deep, rounded scars across their teeth were unlike ordinary prehistoric wear and tear, matching the exact dimensions of holding hard, spherical objects measuring 10 to 20 millimeters across in the mouth for extended periods.[1]

To confirm their hypothesis, the research team—which included scientists from Griffith University, the University of Hasanuddin, and Indonesia's National Research and Innovation Agency—conducted chemical analyses on the dental calculus. They detected arecoline, the primary psychoactive alkaloid found in the seeds of the Areca catechu palm, commonly known as the betel nut.[1]

"Emerging by up to 25,000 years ago in Sulawesi, thus long preceding the onset of agriculture, betel nut-sucking may be the earliest evidence for drug use anywhere in the world," said Professor Adam Brumm, an archaeologist at Griffith University and the study's lead author.

Today, betel nut is the world's fourth most widely consumed psychoactive substance, used by an estimated one in ten people globally. Modern users typically chew the processed seed as a "quid" mixed with slaked lime, which triggers a chemical reaction that rapidly releases arecoline into the bloodstream, inducing mild euphoria and heightened alertness.[3]

The Ice Age foragers, however, employed a simpler method. Laboratory experiments using genetically engineered frog eggs with human neuroreceptors demonstrated that simply sucking on the intact nut releases sufficient levels of arecoline to produce a physiological effect, even without the addition of slaked lime or crushing the seed.[1]

The researchers suspect the habit may have originated as a primitive medical treatment. Arecoline acts as a natural analgesic, and both prehistoric individuals suffered from severe dental decay prior to the extreme wear. The more they sucked on the nut to relieve their toothaches, the worse the structural damage to their teeth became.

Over years of continuous use, the hard, abrasive seeds wore down the foragers' teeth so severely that the inner pulp chambers became completely exposed. This extreme wear would have caused chronic infections and intense pain, creating a vicious cycle where the individuals likely consumed more of the analgesic nuts to cope with the damage caused by the habit itself.

The findings suggest that modern drug-taking behaviors are deeply rooted in ancient foraging traditions, rather than being a byproduct of settled farming societies. Future excavations across Southeast Asia will now look for similar dental wear patterns, as archaeologists re-examine older skeletal remains to determine just how far back the human pursuit of altered states truly goes.[4]