What do joke-lovers and junkies have in common? According to new research, they’re both responding to the same kind of “high.” The study suggests that genuine laughter releases endorphins in the brain, chemicals that activate the same receptors as drugs like heroin, to pain-killing and euphoria-producing effects.
Researchers led by Oxford University’s Robin Dunbar conducted a series of experiments — both in the lab and at the Edinburgh Fringe Festival — to tease out the effect of laughter on people’s ability to withstand pain.
Previous research has linked hearty ha ha‘s with pain relief. Watching comedy videos, for example, has been shown to decrease hospital patients’ need for opioid painkillers. But it wasn’t clear whether it was laughter itself or general positive emotions that were responsible for relieving pain.
In the new study, scientists tested dozens of participants’ tolerance to pain through various methods: a tightening blood pressure cuff, a frozen wine-chilling sleeve placed around the arm, or a strenuous exercise in which participants had to hold themselves against a wall with their legs bent at a 90-degree angle, as if sitting on a chair. (Trust me, it hurts).
In several lab experiments, the researchers subjected people to the painful stimuli both before and after exposing them to episodes of comedy, including video clips of shows like South Park, The Simpsons and Friends or clips of stand-up by performers like Eddie Izzard. The lone field experiment at the comedy festival involved people who had either watched or acted in comic performances.
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Viewing or participating in comedy led to higher pain tolerance, the researchers found, and there was a dose-related response to laughter: people who laughed more felt less pain later.
In one experiment, researchers compared the effect of watching funny videos with watching feel-good ones, such as a nature video from the series Planet Earth. Turns out, it’s the laughter, not the positive emotion, that elicits pain relief.
Laughing along with other people was also better at relieving pain than laughing alone, and that, according to Dunbar, may be the key to its effects. As the New York Times reported:
Dr. Dunbar thinks laughter may have been favored by evolution because it helped bring human groups together, the way other activities like dancing and singing do. Those activities also produce endorphins, he said, and physical activity is important in them as well. “Laughter is an early mechanism to bond social groups,” he said. “Primates use it.”
The current research did not directly measure endorphins in the brain, but prior studies of opioid-blocking drugs in humans and animals show that endorphin activity is tied to pain relief. Earlier research shows also that endorphins are important for bonding between parents and children. Endorphins are released in babies’ brains when a soothing parent responds to their cries, providing safety, warmth and food; babies come to connect that endorphin-induced stress relief with their parents’ presence. Research has further shown that opioids are one of the few things that can ease the cries of young animals that have been separated from their mothers.
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This may help explain why childhood trauma — particularly abuse and neglect — dramatically raises a person’s risk of future heroin or prescription opioid addiction. When a person’s stress system becomes overactive in the absence of parental nurture or social support, he is more likely to seek external opioid drugs to soothe it.
Increasingly, research finds that emotional and physical pain are not distinct and that social contact, whether it be a parent’s touch or a friend’s joke, can provide relief. That should be good news to all those working comedians out there—or maybe, a bit more pressure. If they’re not laughing, they’re may be hurting!
The study was published in the Proceedings of the Royal Society B.
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Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.