Popular Painkiller May Subdue Positive Feelings

In addition to relieving pain, acetaminophen (Tylenol) may cause patients to experience less intense emotional responses.

Previous research has suggested acetaminophen may alleviate not only physical pain, but also psychological pain. A new study, published online in Psychological Science, set out to determine whether the drug affects positive emotions, as well.

The study’s 82 participants—half of whom were given 1000 mg of Tylenol and the other half placebo—were asked to view 40 photographs of unpleasant images (crying and malnourished children), pleasant images (young children playing with cats), and neutral images (a cow in a field). Participants were then asked to rate each picture on a scale of -5 (extremely negative) to +5 (extremely positive).

After viewing the photographs once more, participants were asked to rate the extent to which each picture made them feel, from 0 (little or no emotion) to 10 (intense amount of emotion).

Those who received acetaminophen rated the photographs more moderately than those who did not, with the former group rating unpleasant pictures less negatively and pleasant pictures less positively than the latter group, the research team found. Both groups rated neutral pictures similarly.

The most emotionally jarring photos of malnourished child and kids playing with kittens elicited a stronger overall emotional reaction from those who received placebo compared with those who took Tylenol.

“This means that using Tylenol or similar products might have broader consequences than previously thought,” said lead author Geoffrey Durso, a doctoral student in social psychology at The Ohio State University, in a press release. “Rather than just being a pain reliever, acetaminophen can be seen as an all-purpose emotion reliever.”

In exploring explanations for their findings, the researchers considered the possibility that acetaminophen may change how individuals judge magnitude, subduing their broader judgments of everything, rather than simply emotional content.

To test this theory, the research team conducted the same experiment on a separate group of 85 participants. In addition to rating the pictures and their emotional responses, the participants were asked to report how much blue they saw in each photograph.

Once again, the photographs provoked a more intense emotional response in those who received placebo than those who took Tylenol. However, the participants’ judgments of the amount of blue in each image were similar regardless of whether or not they were given acetaminophen.

This indicates the OTC painkiller affects emotional response in particular, not magnitude judgment as a whole.

The researcher team plans to expand upon their findings to determine whether other pain relievers, such as ibuprofen and aspirin, also have an effect on emotional response.