Acetaminophen can blunt empathy

Acetaminophen appears to reduce feelings of empathy in users, according to a new study.

The investigators presented scenarios of positive experiences to 114 students who took acetaminophen (1000 mg) or placebo and found that those who had taken acetaminophen experienced less pleasure and had less empathy towards hypothetical characters compared to those who had taken a placebo.

The ability to recognize pleasure and positivity has not been affected.

"We found that acetaminophen reduced the emotional, though not cognitive, side of empathy," said Dominik Mischkowski, PhD, assistant professor in the Department of Psychology at the University of Toronto. Ohio, Athens. Medscape Medical News.

"But I want to emphasize that this does not mean that you should stop recommending acetaminophen to patients who are suffering pain." The pain is a very aversive experience and an over-the-counter pain reliever is still a very good tool in the toolbox, "he said.

The study was published online on March 29 in Frontiers in psychology.

"Pure" measure of emotion

"The data reported in this article are part of a series of studies examining how the impact of acetaminophen on social influences and behaviors – how you feel towards others and how you interact with them, "said Mischkowski.

"Our previous work was focused on empathy with people experiencing negative emotions, in which we compared people taking acetaminophen to those taking a placebo in their reactions to scenarios." Negative events for people In this study, we found that acetaminophen reduced empathy for pain "he added.

In this study, 114 undergraduate students from Ohio State University were randomly assigned to receive either 1,000 mg of acetaminophen (n = 59) or a placebo in liquid form (n = 55). ).

To measure positive empathy, the investigators presented participants with written scenarios. In a scenario, a man proposes to his girlfriend; in another, a man is happy that a woman who is interested has agreed to an appointment; in a third, a woman receives a pay raise at work; in a fourth, the father of a woman attends his musical performance.

Participants made three measures of positive empathic perception and affective empathy: a measure of one element on perceived positivity, one measure of perceived pleasure and one measure out of six elements of personal pleasure.

In addition, while imagining the feelings involved in each scenario, the participants completed an established measure of six elements of empathic feelings led by others. This tool measured how much the participants felt sympathy, warmth, compassion, sweetness of heart, tenderness and the extent to which they were touched.

The researchers dismissed the initial affective differences between the group receiving acetaminophen and the placebo group by measuring initial affect and sexual arousal, using the respective subscales to an element. the self-assessment manikin.

To determine if acetaminophen modified positive empathy by altering the overall affect, participants completed the program on both positive and negative effects.

At the end of the study, participants were asked if they thought they had used acetaminophen or placebo.

"We wanted to control the basic effects and after receiving the drug because the drug takes time to work, and we wanted a pure measure of emotion not" contaminated "by the drug," Mischkowski said.

Reduced personal pleasure

Researchers used state-specific measures of variance (acetaminophen vs. placebo) as an inter-subject factor to determine whether acetaminophen reduced perceived positivity, perceived pleasure, personal pleasure and empathic feelings.

They found that, compared to placebo, acetaminophen decreased personal pleasure and empathic feelings (personal pleasure: F [1110] = 12.38; P <0.001; η _p ² = 0.101; empathic feelings: F[1110] = 11.67; P <0.001 η _p ² = 0.096).

In contrast, compared to placebo, acetaminophen did not significantly reduce perceived positivity or perceived pleasure (perceived positivity: F [1110] = 2.44; P = .121; η _p ² = 0.022; perceived pleasure: F[1,110] = 2.74; P = 0.101; η _p ² = 0.024).

"According to these findings, acetaminophen would reduce the empathic emotional response by reading that other people had positive experiences, but did not affect the perception of these positive experiences," note the authors.

Neither perceived positivity nor perceived pleasure, nor the two measures combined, moderates the effect of acetaminophen on the reduction of personal pleasure or on feelings of empathy directed by others.

"These findings suggest that empathic perceptions do not account for the effect of acetaminophen on the decrease in empathic affect," the authors write.

Compared to placebo, acetaminophen intake did not change overall positive or negative effect measured one hour after drug administration (just before reading the empathy scenarios).

"The mechanism [of the impact of acetaminophen on empathy] it's not clear, but there are assumptions and speculations, "Mischkowski said.

"Pain and empathy are complex, just as the brain is complex, so if you are targeting pain, you can also target other areas – and the areas involved in emotion processing, emotional awareness and acting on emotions are potential candidates, "he added. added.

He also noted an important warning.

"It's important to put these findings in context and recognize that many people take acetaminophen because they want to treat the pain.The pain itself diminishes our ability to sympathize with others, because it is short-sighted and self-centered, responding to the demands of others – what they need or want, instead you are more focused on your own survival, "he said.

In such a setting, if you relieve pain, you would expect a positive effect of acetaminophen [on empathy]But in my studies, I do not cause pain and I do not see how acetaminophen works with this and whether it improves the social functioning of those who take it for pain, "he added.

Empathy is based on neural processes

Commenting on the study for Medscape Medical NewsMarija-Magdalena Petrinovic, PhD, Lecturer at the Department of Forensic and Neurodevelopmental Sciences, Sackler Center for Translational Neuroscience, Camberwell, London (United Kingdom), did not participate in the research, stated that the Results "provide further support to the" theory of empathy, which suggests that empathy relies on neural processes similar to those underlying the first-hand experience of a patient. given emotion. "

She noted that "this interesting study did not investigate the mechanism by which acetaminophen reduced empathy for pleasant experiences of other people" and that it was "interesting that … acetaminophen has an effect on emotional empathy … but not on cognitive empathy. "

This suggests "a differential regulation of the underlying neural circuits – in other words, different brain circuits regulate different aspects of empathy – by acetaminophen and therefore encourages its subsequent use in validation aimed at discovering the neurobiological mechanisms of empathy. "

Future studies should compare the use of acetaminophen by healthy and painless participants to its use by those suffering from physical pain. They should also involve fMRI measurements of brain activity rather than relying exclusively on self-evaluation, Petrinovic said.

Mischkowski added that he was about to start a study using imagery to probe this issue further.

The study was funded in part by funds from Ohio State University and the National Center for the Advancement of Translational Sciences. The authors and Petrinovic have not revealed any relevant financial relationship.

Psychol before. Posted online 29 March 2019. Full text

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