Compared to other cultures around the world, Americans are big stoners.
About 40 percent of Americans say they've tried marijuana at some point in their lifetimes, a large survey found. That rate was the highest reported across 17 countries, and it's nearly 10 times higher than the global average.
But when it comes to reefer madness, nobody can top the Aka — a group of traditional hunter-gatherers in the Congo Basin.
About 70 percent of Aka men regularly use marijuana, scientists at Washington State University in Vancouver reported last month in the American Journal of Human Biology. By contrast, only about 6 percent of the women partake of the drug.
Many of the Aka men think of cannabis as a performance-enhancing drug, says anthropologist Edward Hagen, who led the study. "They say, 'It keeps me warm, it gives me strength.' "
And others say, they just — well — have a "desire" for cannabis.
But Hagen thinks THC, the main mind-altering ingredient in pot, may serve the Aka men a secondary purpose: It could help get rid of intestinal worms.
On average, the more THC byproduct that Hagen's team found in an Aka man's urine, the fewer worm eggs were present in his gut.
"The heaviest smokers, with everything else being equal, had about half the number of parasitic eggs in their stool, compared to everyone else," Hagen says.
Of course, this result is a simple correlation. Hagen doesn't know if the THC in the men's system is actually keeping the parasitic worms at bay. And taking a few pills is a much easier way to get rid of intestinal worms.
"This is just the first word on this idea, not the last" he says. "We're trying to see if this topic is something to look into further."
THC — and nicotine — are known to kill intestinal worms in a Petri dish. And many worms make their way to the gut via the lungs. "The worms' larval stage is in the lung," Hagan says. "When you smoke you just blast them with THC or nicotine directly."
Traditional groups in the Congo Basin smoke a variety of psychoactive substances, including tobacco and motunga — a plant found in nearby forests.
"They dry the leaves on a fire," Hagen says. "We smoked it while we were there. Motunga has the same effect as a cigarette: You get a slight buzz."
The Aka also make a tea with motunga leaves, Hagen says. "Drinking that tea has been shown to kill intestinal worms."