One of the most widely used drugs in the United States – and the most commonly used painkiller worldwide – may be doing much more than simply relieving headaches, recent evidence suggests.
Paracetamol, also known as paracetamol and sold widely under the brand names Tylenol and Panadol, also increases risk-taking, according to a September 2020 study that measured changes in people’s behavior when under the influence of a common drug without recipe.
“Paracetamol seems to make people feel less negative emotions when they consider risky activities – they just don’t feel so scared,” said Ohio State University neuroscientist Baldwin Way in September 2020.
“With nearly 25 percent of the United States population taking acetaminophen every week, reduced risk perception and increased risk can have important effects on society.”
The findings add to recent research that suggests that the effects of paracetamol on pain reduction also extend to various psychological processes, decreasing people’s receptivity to hurt feelings, experiencing reduced empathy and even dulling cognitive functions.
Similarly, recent research suggests that people’s affective capacity to perceive and assess risks can be impaired when they take paracetamol. While the effects may be mild, they are definitely worth noting, as paracetamol is the most common drug ingredient in America, found in more than 600 different types of over-the-counter and over-the-counter medications.
In a series of experiments involving more than 500 university students as participants, Way and his team measured how a single 1,000 mg dose of paracetamol (the maximum recommended single dose for adults) randomly distributed to participants affected their risk behavior, compared to placebos given randomly to a control group.
In each of the experiments, participants had to pump an unfilled balloon on the computer screen, with each bomb making imaginary money. His instructions were to make as much imaginary money as possible by pumping the balloon as much as possible, but to make sure you didn’t pop the balloon, in which case they would lose the money.
The results showed that students who took paracetamol took significantly more risks during exercise, compared to the more cautious and conservative placebo group. Overall, those who took paracetamol pumped (and popped) their balloons more than the controls.
“If you are risk averse, you can pump a few times and then decide to cash out because you don’t want the balloon to burst and lose your money,” said Way.
“But for those who are taking acetaminophen, as the balloon gets bigger, we believe that they have less anxiety and less negative emotion about the size of the balloon and the possibility of bursting.”
In addition to the balloon simulation, participants also completed surveys during two of the experiments, assessing the perceived risk level in various hypothetical scenarios, such as betting a day’s income on a sporting event, bungee jumping from a high bridge or driving a car without seat belt.
In one study, the consumption of paracetamol appeared to reduce the perceived risk compared to the control group, although in another similar study, the same effect was not observed.
Overall, however, based on an average of results across the various tests, the team concludes that there is a significant relationship between taking paracetamol and choosing more risk, even though the observed effect may be mild.
That said, they recognize that the drug’s apparent effects on risky behavior can also be interpreted through other types of psychological processes, such as reducing anxiety, perhaps.
“It may be that as the balloon increases in size, those taking the placebo experience an increasing amount of anxiety about a possible burst,” explain the researchers.
“When anxiety becomes excessive, they end the test. Paracetamol can reduce that anxiety, leading to greater risk taking.”
Exploring such alternative psychological explanations for this phenomenon – as well as investigating the biological mechanisms responsible for the effects of paracetamol on people’s choices in situations like this – should be addressed in future research, the team said.
While they are doing this, scientists will undoubtedly also have future opportunities to further investigate the role and efficacy of paracetamol in pain relief more broadly, after studies in recent years have found that in many medical settings, the drug it can be ineffective in relieving pain, and is sometimes no better than a placebo, in addition to inviting other types of health problems.
Despite the seriousness of these findings, paracetamol remains one of the most widely used drugs in the world, considered an essential drug by the World Health Organization and recommended by the CDC as the main drug you should probably take to relieve symptoms, if you think who may have coronavirus.
In light of what we’re discovering about paracetamol, we may want to rethink some of that advice, Way said.
“Perhaps someone with mild symptoms of COVID-19 does not think it is so risky to leave the house and meet people if they are taking acetaminophen,” said Way.
“We really need more research on the effects of acetaminophen and other over-the-counter drugs on the choices and risks we take.”
The results are reported in Cognitive and Affective Social Neuroscience.
A version of this article was first published in September 2020.