Researchers at the Ohio State University studying the widespread pain reliever acetaminophen recently discovered that the drug can blunt strong emotions, a previously unknown side effect. In their study, the researchers found that participants who took acetaminophen reported less strong reactions when viewing both pleasant and disturbing photographs compared to those who took placebos (1). Previous research has shown that acetaminophen lessens psychological pain as well as physical pain (2). The new study takes these results one step further by showing that acetaminophen specifically reduces the strength of users’ emotions (1).
Acetaminophen, the main ingredient of the over-the-counter drug Tylenol, has been used for decades as a drug ingredient in the United States. This is the first time that a psychological side effect as been documented. Geoffrey Durso, lead author of the study, says that the results suggest Tylenol and similar products may have broader consequences than previously thought (1).
Acetaminophen is the main ingredient in pain medication such as Tylenol. (Source: Wikimedia Commons)
The research was divided into two studies. The first involved 82 participants randomly assigned to take a dose of acetaminophen or a placebo. Then the participants were asked to rank 40 pictures on an 11-point scale from -5 (extremely negative) to 5 (extremely positive).
The participants were then shown the pictures again and asked to rate their emotional reaction from a scale of 0 (little to no emotion) to 10 (extreme emotion) (2). The results showed that those who took acetaminophen rated the photographs less extremely than those who did not. Positive photos were not seen as positively, and negative photos were not seen as negatively; all participants rated neutral photos similarly.
The second study involved 85 different participants who completed the same tasks in the first study. Then, the participants saw the images once again, this time to judge how much of the color blue each picture contained on a scale from 0 (no blue) to 10 (100% blue). Just like those in the first study, the participants had similar levels of emotional reaction to the pictures. However, the evaluations of blue levels were alike across the board. This suggests that acetaminophen affects emotional judgments but not all magnitude judgments (2).
These results may have impact not only on the pharmaceutical industry but also on psychology. Acetaminophen’s unexpected side effect might offer new forms of medication or new ways of making drugs. In addition, the research presented may help answer the question of whether the same biochemical factors control both positive and negative emotional reactions.
Reference:
1: Ohio State University. (2015, April 13). Your pain reliever may also be diminishing your joy.ScienceDaily. Retrieved April 19, 2015 from www.sciencedaily.com/releases/2015/04/150413091647.htm
2: G. R. O. Durso, A. Luttrell, B. M. Way. Over-the-Counter Relief From Pains and Pleasures Alike: Acetaminophen Blunts Evaluation Sensitivity to Both Negative and Positive Stimuli. Psychological Science, 2015; DOI: 10.1177/0956797615570366