HQ Team
November 14, 2022: The most commonly consumed analgesic in the world, acetaminophen or paracetamol, can induce risky behaviour, according to a study.
Commonly known as Tylenol, this analgesic is recommended as the first line of therapy for pain and fever by the World Health Organization (WHO). This drug was initially approved by the U.S. FDA in 1951 and is available in syrup form, regular tablets, effervescent tablets, injections, and suppositories.
Acetaminophen is often found combined with other drugs in more than 600 over-the-counter (OTC) allergy medications, cold medications, sleep medications, pain relievers, and other products.19
The study from 2020 measured changes in people’s behaviour when under the influence of this medication.
“Acetaminophen seems to make people feel less negative emotion when they consider risky activities – they just don’t feel as scared,” explained neuroscientist Baldwin Way from The Ohio State University when the findings were published.
“With nearly 25 per cent of the population in the US taking acetaminophen each week, reduced risk perceptions and increased risk-taking could have important effects on society.”
Way conducted the study with Alexis Keaveney, a former doctoral student at Ohio State, and Ellen Peters, a former professor at Ohio State. The study was published online in the journal Social Cognitive and Affective Neuroscience.
Acetaminophen and risk-taking behaviour
The research involved 500 university students. Way and his team measured how a single 1,000 mg dose of acetaminophen randomly assigned to participants affected their risk-taking behaviour, compared to random placebos given to a control group.
The participants were asked to inflate a balloon on a computer screen, with every single pump of the balloon earning imaginary money. The aim was to earn as much imaginary money as possible by pumping the balloon but to make sure not to pop the balloon, in which case they would lose the money.
The results showed that the students who took acetaminophen engaged in significantly more risk-taking during the exercise relative to the more cautious and conservative placebo group. Participants on acetaminophen seemed to pump more with resultant more burst balloons than the controls.
“If you’re risk-averse, you may pump a few times and then decide to cash out because you don’t want the balloon to burst and lose your money,” Way said.
“But for those who are on acetaminophen, as the balloon gets bigger, we believe they have less anxiety and less negative emotion about how big the balloon is getting and the possibility of it bursting.”
In one study, 189 college students took either 1,000 mg of acetaminophen or a placebo that looked the same. After the drug took effect, the participants were asked to rate on a scale of 1 to 7 some activities as risky or not so risky. Results showed that those under the influence of acetaminophen-rated activities like bungee jumping, walking home alone at night in an unsafe area of town, starting a new career in their mid-30s, and taking a skydiving class as less risky than those who took the placebo.
Reduced anxiety
The drug’s apparent effects on risk-taking behaviour could also be interpreted via other kinds of psychological processes, such as reduced anxiety.
“It may be that as the balloon increases in size, those on placebo feel increasing amounts of anxiety about a potential burst,” the researchers explained.
“When the anxiety becomes too much, they end the trial. Acetaminophen may reduce this anxiety, thus leading to greater risk-taking.”
A growing body of research shows acetaminophen lowers people’s receptivity to hurt feelings, experiencing reduced empathy, and even blunts cognitive functions.
The effects on risky behaviour might be slight, but it s is worth taking note of, considering it is widely consumed as an over-the-counter medicine.
The team said that exploring such psychological alternative explanations for this phenomenon and investigating the biological mechanisms responsible for acetaminophen’s effects on people’s choices in situations like this should be addressed in future research.
The findings were reported in Social Cognitive and Affective Neuroscience.
