Humans
PUBLISHED
What you'll discover in this article:
- Dental wear on 25,000-year-old human teeth indicates long-term, daily sucking on psychoactive betel nuts.
- This represents the earliest evidence for drug use in human history.
- Study author Professor Adam Brumm told IFLScience that sucking on betel nuts doesn't produce the same high as chewing them in a "quid", but this prehistoric user does appear to have become addicted.
Every human society uses some form of mind-altering drug, and new evidence suggests that we’ve been ingesting these substances for tens of thousands of years.
Analyzing the teeth of a 25,000-year-old skeleton from Sulawesi, Indonesia, researchers have deduced that this individual habitually sucked on betel nuts, and probably developed an addiction to this popular stimulant.
Widely consumed across southeast Asia and the Pacific, betel nuts are the world’s fourth most popular drug, behind alcohol, caffeine, and nicotine. These days, the nuts are typically mixed with slaked lime and chewed as a “quid” in order to release the psychoactive compound arecoline, triggering mild euphoria and heightened alertness.
Although the roots of this practice are poorly understood, it is generally assumed that betel chewing does not pre-date the Bronze Age, some 3,500 years ago.
We suspect this practice was not just habitual – it was an addiction.
Professor Adam Brumm
However, researchers have now uncovered two prehistoric hunter-gatherer skeletons displaying deep, rounded grooves in their teeth, which appear to have been caused by continually sucking on betel nuts over the course of many years.
The oldest of the pair dates to between 25,000 and 16,000 years ago, indicating that humans have been using narcotics since at least the late Pleistocene.
In an email to IFLScience, study author Professor Adam Brumm from Griffith University explained that “the modern custom of chewing betel nut in a a quid with slaked lime appears to have evolved from a much older habit of simply sucking on intact betel nuts, a practice dating to as early as 25,000 years ago in Sulawesi.”
To determine what effect this might have had, the team soaked betel nuts in artificial saliva, which they then used to stimulate cloned human receptors. This indicated that just sucking on the nuts releases enough arecoline to alter brain function, although not to the same extent as chewing on a quid.
Biochemical analyses, meanwhile, detected arecoline on the ancient teeth, confirming that these prehistoric nut suckers experienced some sort of psychoactive effect.
Ironically, this medicinal remedy for oral pain actually made their dental health much worse over the long term.
Professor Adam Brumm
“As far as we can ascertain, sucking the nut on its own does not bring on the betel 'high',” says Brumm. “But based on the depth and extent of the tooth grooves, the ancient hunter-gatherers from Sulawesi were clearly sucking on betel nuts for prolonged periods on a very regular basis, probably daily for many years, so we suspect this practice was not just habitual - it was an addiction,” he adds.
Given the atrocious dental health of these specimens, the researchers propose that the pair may have initially sought out betel nuts due to their painkilling effects, possibly in an attempt to alleviate toothache.
“Ironically, this medicinal remedy for oral pain actually made their dental health much worse over the long term, wearing down their teeth so badly that in some cases the tooth’s pulp cavity or 'living core' became exposed,” says Brumm.
“At this point we suspect these early foragers were caught in a self-perpetuating cycle where they were pathologically addicted to nut-sucking to treat the pain of a condition caused by this practice itself,” he explains.
More broadly, these new insights reveal that humans have always been susceptible to the tumbling down the slippery slope that is drug use, and that addiction is not an exclusively modern phenomenon. Until recently, it had been suggested that the trouble only started once we invented beer at the onset of the agricultural revolution, yet that narrative now appears inaccurate.
“The new findings from Sulawesi suggest an earlier origin for the human use of neuroactive plant drugs, and indeed for habitual drug use and the negative health outcomes that result, a universal part of the human condition today,” says Brumm.
The study is published in the journal Science Advances.
