Tylenol may be good at dulling pain, but new research suggests it may also dull something else - your empathy.
A recent study by researchers at The Ohio State University found that when participants taking acetaminophen were told about others' pain and suffering, they weren't as concerned as those who were not on the drug.
"These findings suggest other people's pain doesn't seem as big of a deal to you when you've taken acetaminophen," Dominik Mischkowski, co-author of the study and a former Ph.D. student at Ohio State, now at the National Institutes of Health, said in a press release.
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"Acetaminophen can reduce empathy as well as serve as a painkiller."
How can a pain reliever influence empathy? Currently researchers have no idea.
"We don't know why acetaminophen is having these effects, but it is concerning," said Baldwin Way, senior author of the study and an assistant professor of psychology and member of the Ohio State Wexner Medical Center's Institute for Behavioral Medicine Research.
Way conducted an earlier study that also found acetaminophen also appears to diminish feelings of joy.
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The latest research was done in three parts. For part one 40 college students drank a solution containing 1,000 mg of acetaminophen, while 40 others drank a placebo solution that contained no drug. After waiting an hour for the medicine to take effect, the entire group was asked to read about people undergoing painful events, such as getting a deep knife wound or losing a parent.
The students who had taken acetaminophen rated the pain and suffering of the people in the scenarios to be less than did those who took the placebo.
Drug distribution was set up the same way among a second group of 114 college students. The students were then subjected to blasts of white noise that ranged from 75 to 105 decibels. They were asked to rate how unpleasant the blasts were and also to rate how much pain the blasts would cause others.
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The students who had taken the drug found the blasts to be more bearable than those who had not taken the drug. They also thought it would be less unpleasant for others.
"Acetaminophen reduced the pain they felt, but it also reduced their empathy for others who were experiencing the same noise blasts," Mischkowski said.
A final group was instructed to participate in a "game" in which one person in a group of three was actively excluded. Later each student was asked to rate to what extent the game hurt the feelings of the excluded person. The group students who had taken acetaminophen reported significantly less concern for the excluded people.
"In light of those results, it is understandable why using Tylenol to reduce your pain may also reduce your ability to feel other people's pain as well," Way said.
The researchers are trying to get to the bottom of how acetaminophen influences emotion and behavior. And they're also starting investigations into whether another pain killer, ibuprofen, may have similar effects.
The study was published online in the journal Social Cognitive and Affective Neuroscience.