A new study revealed that taking acetaminophen, the ingredient of the popular painkiller Tylenol, not only reduces pain but also decreases a person’s empathy as well. The study, published on May 5 in the journal Social Cognitive and Affective Neuroscience, states that those who took the drug seem to be indifferent to other people’s pain and suffering.

The researchers from the Ohio State University do not know why the drug produces these effects. The findings correspond to an earlier research that showed the painkiller also dulls positive feelings like joy, which was also conducted by the new study’s researcher Baldwin Way.

“Empathy is important,” says Way, an assistant professor of psychology and member of the Ohio State Wexner Medical Centre’s Institute for Behavioural Medicine Research. “If you are having an argument with your spouse and you just took acetaminophen, this research suggests you might be less understanding of what you did to hurt your spouse’s feelings.”


Kids comforting their friends. Credit: Preachers Institute

The researchers studied 80 college students in their first experiment. Half of these participants unsuspectingly took a liquid with 1,000 milligrammes of acetaminophen while the other only took a placebo solution without the drug.

These students were asked to read eight short scenarios involving a person suffering from pain an hour after taking the solution. One scenario depicted the story of a person hurt by a knife cut that went all the way to the bone and another scenario told the story of a man experiencing his father’s death. Based on a pain scale from one to five, with one as no pain and five as worst pain, the participants who drank the acetaminophen rated those characters from those awful scenarios as experiencing less pain.

For the team’s second experiment, they asked half of the 114 college students to take acetaminophen and the other half with the placebo. Those who took the placebo claimed that the sounds blasted by the researchers are painless and not unpleasant. Another experiment revealed that those who took the drug did not feel sorry for those people who got rejected from a game.

The team is currently exploring the other effects of acetaminophen on other human emotions and behaviours. The researchers also started to study if another painkiller called ibuprofen can also lead to these similar effects.