The earliest evidence of human drug use dates back 25,000 years to an ancient hunter-gatherer in Indonesia who consumed mind-altering betel nuts, according to a new study by Griffith University scientists. This finding significantly pushes back the previously accepted timeline for human drug use, which was thought to have begun around 13,000 years ago during the Neolithic period.
Betel nuts, which are still consumed in the Asia-Pacific region, induce mild euphoria and heightened alertness. Professor Adam Brumm, the lead author of the study, noted that betel nut is the world's fourth most widely used psychoactive substance, after alcohol, caffeine, and nicotine, despite being less known in Western societies.
The research team discovered the remains of two early human foragers on the Indonesian island of Sulawesi. One individual's remains dated to between 25,000 and 16,000 years ago, and the other to between 7,600 and 6,300 years ago. Both individuals exhibited unusual dental wear patterns, characterized by deep, rounded grooves in their teeth, suggesting they had been sucking on whole betel nuts.
Historically, it was believed that betel nuts needed to be chewed to release their psychoactive compound, arecoline. However, the study's experiments demonstrated that sucking on intact betel nuts is sufficient to release arecoline in amounts that can physiologically affect brain function. Researchers tested broths created by soaking betel nuts in artificial saliva against cloned human receptors.
It is theorized that these ancient individuals may have initially used betel nuts to alleviate toothache. However, the prolonged habit of sucking on the hard nuts led to severe dental wear, exposing the inner pulp and causing significant pain, difficulty eating, and increased risk of chronic infection. This may have created a cycle of continued use.
"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," Professor Brumm concluded. The findings suggest that some modern drug-taking behaviors have deep roots in ancient forager traditions.