Acetaminophen, the active ingredient in Tylenol, could be doing more than just dulling pain—a new study found that it dulls all emotions, both positive and negative. "It seems to take the highs off your daily highs and the lows off your daily lows," according to Baldwin Way, one of the study’s researchers, who is a psychologist at Ohio State University.

In the study of 82 college students, half the participants took 1,000 mg of acetaminophen (equivalent to two extra-strength Tylenol) and the other half took a placebo. After waiting an hour for the drugs to take effect, participants were shown 40 pictures from a database of photos that researchers around world use to elicit emotional responses. They ranged from very unpleasant (crying and malnourished children) to neutral (a cow in a field) to very pleasant (children playing with kittens). Participants ranked each picture according to how pleasant or upsetting each photo was and how powerful they thought the image was.

Participants who took the acetaminophen rated the unpleasant photos less negatively than those who took the placebo. They also rated the pleasant photos less positively than those who took the placebo. This study builds on research published in 2010 that found acetaminophen can reduce psychological pain as well as physical pain. At first glance, that may seem like a positive attribute. According to the new study, however, the drug also reduces feelings of happiness.

Each week, about 52 million people in America take a product containing acetaminophen. In addition to being a common ingredient in over-the-counter painkillers and cold remedies, it’s a common ingredient in opioid painkillers (often called narcotics).

This study is particularly interesting in the context of chronic pain. The primary drugs used to treat chronic pain are painkillers, most of which contain acetaminophen. People with chronic pain are also at a higher risk of depression than the general population. This is usually attributed to the physical and emotional strain of chronic pain. Could the drugs used to treat chronic pain, even the OTC painkillers that so many people think are harmless, be contributing to the higher incidence of depression?

REFERENCES

Grabmeier, J. (2015, April 13). Your pain reliever may also be diminishing your joy. Retrieved April 16, 2015, from http://news.osu.edu/news/2015/04/13/emotion-reliever/

Durso, G. R., Luttrell, A., & Way, B. M. (2015). Over-the-Counter Relief From Pains and Pleasures Alike Acetaminophen Blunts Evaluation Sensitivity to Both Negative and Positive Stimuli. Psychological Science, 0956797615570366.

Aubrey, A. (2015, April 16). Tylenol Might Dull Emotional Pain, Too. Retrieved April 16, 2015, from http://www.wbur.org/npr/399810896/tylenol-might-dull-emotional-pain-too?ft=nprml&f=399810896