The paracetamol (acetaminophen) is a widely used drug for its pain and fever properties. As with other medications, its use can have unwanted side effects. Until now, it was known, for example, that taking it in high doses negatively affected the liver.

Recent research from Ohio University seems to indicate that the active ingredient in acetaminophen, which is also found in other medications, decreases the ability to feel both positive and negative emotions.

Acetaminophen does not only affect pain

The study of the relationship between paracetamol and emotions is not new; previous research found that subjects who took paracetamol for three weeks felt less emotional pain than people who took a placebo. But the new study, published in Psychological Science , appears to show that this drug affects positive emotions as well, not just negative ones.

The study and its results

The research, led by Geoffrey R. O. Durso, Andrew Luttrell and Baldwin M., was conducted at Ohio University. Two groups of 41 subjects each were formed. The first group received a dose of 1000 mg of acetaminophen and the second group received a placebo (an alleged drug). One hour later (time needed for the acetaminophen to take effect) they were shown a series of pictures to elicit either negative or positive emotions. These images had been selected to provoke strong emotional reactions. The subjects had to evaluate from +5 (most positive) to -5 (most negative) their positive or negative perception of the image. After looking at the images and evaluating them a first time, they were presented with the sequence of images again for a second evaluation.

The results revealed that the group that had consumed paracetamol felt less intense emotional reactions to the images, i.e. negative images were assessed as less negative, and positive images were assessed as less positive.

To rule out that the perception of other image qualities (such as color intensity, etc…) had not affected the emotional assessment, a second study was conducted. The results showed that paracetamol did not alter the visual perception of the image.

It should be mentioned, that the difference in the scores of both groups was not very large. The average of the scores of the placebo group was 6.76, while those of the group that had taken paracetamol were 5.85.

Other studies in relation to pain and emotions

We already commented in the article “The Phantom Limb: Mirror Box Therapy” that the studies of Ronald Melzack, a researcher and professor of psychology at McGill University in Canada, gave rise to the Neuromatrix Theory . This theory attributes the diffusion of pain and its transmission through the body to a complex system. Various areas (of the central and peripheral nervous system, the autonomic nervous system and the endocrine system) intervene in the system and are directly influenced by various psychological, emotional, genetic and social factors.

Another study, conducted by Naomi Eisenberger, a researcher at the University of California, Los Angeles (UCLA), seems to indicate that physical pain and social pain are processed in the same brain regions. These brain regions are activated in a similar way in the face of physical pain or social rejection, such as a break-up. In addition, people “who are more sensitive to physical pain are also more sensitive to social pain” concludes the author of the research.

If it is true that paracetamol affects emotions, will other painkillers such as Aspirin or Ibuprofen also have an effect on emotions? There will certainly be further research in this area.