A standard dose of the common painkiller acetaminophen made people noticeably less cautious when facing a frightening drop, according to a new experiment. Participants who took the drug stepped out onto a virtual plank 80 stories up sooner, walked along it faster, and their hearts raced less than those who swallowed a placebo.
The study was carried out by Savannah Yerman of Loyola University Maryland and Pat Barclay of the University of Guelph in Canada. It was published online in the journal Emotion on February 17, 2026, under the title “Behavioral Consequences of Blunting Fear With Acetaminophen”.
Acetaminophen, also called paracetamol, is already known to dull a range of emotional reactions, from hurt feelings to empathy. The researchers wanted to know whether it also dulls fear, the emotion that keeps people away from danger.
A plank, a headset and an 80-story drop
The team recruited 260 participants, mostly students, at the University of Guelph between 2022 and 2023. In a double-blind design, 129 received two capsules containing 1,000 mg of acetaminophen in total and 131 received identical capsules of inert cellulose. Neither the participants nor the experimenters knew who got what, and participants could not guess their condition afterward.
After waiting an hour for the drug to be absorbed, each person put on a Meta Quest 2 headset and rode a virtual elevator to the top of a skyscraper. The doors opened onto a narrow plank jutting out over the street. To make it feel real, a 2-meter wooden plank lay on the lab floor, lined up with the virtual one and growing wobblier toward its far end.
The task worked. Heart rates rose by about 34 beats per minute on average, people took around 15 seconds to get both feet on the plank, and they then inched along at about 5 centimeters per second. Two participants were too scared to step on at all.
Faster, calmer and less careful
Those on acetaminophen took less time to step onto the plank: a median of two seconds faster, which the authors put at 17%. Once on it, they walked at 5.47 centimeters per second compared with 4.48 for the placebo group, a 22% difference.
Their bodies also reacted less. Resting heart rates were the same in both groups before the walk, but during it the acetaminophen group’s heart rate rose by 31.95 beats per minute on average, against 36.41 for the placebo group, about 12% less.
A similar pattern showed up in an optional second walk in which virtual spiders swarmed the plank. Participants on the drug walked marginally faster and their heart rates again rose significantly less.
What the drug did not change
Strikingly, people on acetaminophen did not report feeling much less afraid. Their combined fear scores were 5.96 on a 10-point scale versus 6.23 for placebo, a difference that was not statistically significant.
The authors argue that the behavioral and physical measures matter more than what people say they feel, and note that all of them were correlated with self-reported fear. The drug also had no measurable effect on how far people walked, how much they looked down, or how fast they returned to the elevator.
The researchers point to a practical worry. If people on acetaminophen act less cautiously when there is real danger, they write, they might for example be more likely to speed while driving. They also suggest, purely as a question for future clinical trials and not as medical advice, that the drug’s dampening of fear could one day be tested as an aid to exposure therapy for phobias.
Study Details:
- Title: Behavioral Consequences of Blunting Fear With Acetaminophen
- Authors: Savannah Yerman, Pat Barclay
- Journal: Emotion
- Publication Date: February 17, 2026
- DOI: 10.1037/emo0001610