A new study by an Ohio University faculty member showed that acetaminophen limited the positive empathy a person has for others while taking it. The study, titled "A Social Analgesic? Acetaminophen (Paracetamol) Reduces Positive Empathy" was conducted by visiting assistant professor Dominik Mischkowski.

In the study, 114 participants were either given 1,000 milligrams of acetaminophen or an inert placebo. The experiment was conducted double blind—neither the study coordinators nor the participants were aware if they were being given acetaminophen or the placebo.

After an hour, participants looked at four scenarios describing two men and women having a positive experience. While looking at each scenario, participants rated how positive they felt the scenarios were, how much pleasure they thought those in the scenario were experiencing, how much pleasure participants themselves were experiencing while reading these scenarios, and how much empathy they had for people in the scenario.

The study found that while the acetaminophen reduced personal pleasure and empathic feelings, it has no effect on perceptions of pleasure and positivity.

"I'm still surprised about the striking psychological effects of such a common painkiller such as acetaminophen," Mischkowski said. "However, based on previous research we expect acetaminophen not only to reduce empathy for pain but also empathy for pleasure. It is nice that it came out that way."

This is not the first time that Mischkowski has looked at acetaminophen and its effects. In 2016, he published a study also looking at acetaminophen. "We conducted the original study to test how pharmacologically reducing pain responsiveness (via acetaminophen) also reduces responsiveness to the pain of others," Mischkowski said. During the previous study, participants responded to written scenarios about somebody in physical or emotional pain.

The current study was aimed at expanding on the previous findings. These expanded results are important when it comes to fully understanding the effects of acetaminophen. Acetaminophen is found in many popular over-the-counter pain- and fever-reducing medications. "Given that an estimated quarter of all US-American adults consume a drug containing acetaminophen every week, this research really matters," Mischkowski said.