tylenolDo you take acetaminophen (Tylenol) to treat menstrual pain, migraines, headaches, back aches or other discomfort? You may be surprised to discover that this popular over-the-counter pain remedy doesn’t just impact pain. Research shows it also affects your moods and behavior in unexpected ways. Here’s what the studies show happens to you whenever you pop this pill:

You make more errors–without realizing it

In a new study in the journal Social Cognitive and Affective Neuroscience, researchers gave 30 study volunteers 1,000 mg. of acetaminophen (the maximum standard adult dose) and another 30 a placebo, then had them do a task that measures mental accuracy. Called the “Go or No Go”, participants were asked to hit a Go button every time the letter F flashed on a screen but refrain from hitting the button if an E flashed on the screen.

What happened next? Those who took acetaminophen made more errors than those given the placebo–but they were unaware they were making the mistakes. The study authors, therefore, concluded that acetaminophen appears to reduce your ability to recognize an error.

While at first this seems like a pretty innocuous effect unless you’re taking an exam, the researchers point out that in the real world, this can have important consequences. That’s because it means you’re less likely to make sudden corrections when needed, for instance, if you’re talking to a friend while crossing a street and you need to react to an erratic driver.

You’re not as happy or as sad

In a 2015 study from Ohio State University, 41 volunteers were given 1,000 mg. of acetaminophen and another 41 took a placebo. After waiting 60 minutes for the drug’s full effect to kick in, researchers showed the participants 40 images designed to trigger a range of emotional responses, including feeling positive (such as young children playing with cats), negative (such as crying, malnourished children) and neutral (such as a cow in a field).

The result? The folks who took acetaminophen experienced about 20% less intense positive and negative reactions than those who didn’t take the drug, suggesting that it blunts both your positive and negative emotions.

Social rejection doesn’t feel as painful

At some point, we’ve all experienced the sting of being rejected, for instance, by a friend, partner, family member or colleague. Well, according to a 2010 study in the journal Psychological Science, when taken over time, acetaminophen can make social rejection less emotionally painful.

To prove this, the researchers tested this effect two ways: In their first experiment, 31 volunteers took a 500 mg. dose of acetaminophen in the morning and 500 mg. one hour before bedtime while another 31 volunteers took a placebo morning and night every day for three weeks. Over the course of the experiment, those who took the drug reported feeling less hurt feelings related to social interactions, such as perceived exclusion or teasing. Compare that to the placebo group who experienced no change in hurt feelings.

In their second experiment, one group of 10 participants took a daily 1,000 mg. dose of acetaminophen in the morning and a 1,000 mg. dose one hour before bedtime while a group of 15 participants took a daily placebo morning and night. At the end of the three weeks, both groups were instructed to play a video game that they didn’t know was purposely rigged to make them feel socially rejected. While they played, the researchers examined their brain activity through functional magnetic resonance imaging (fMRI). What they discovered: In response to social rejection, folks in the acetaminophen group had less activity in brain regions associated with social pain and physical pain (the dorsal anterior cingulate cortex and anterior insula) while these brain areas were more highly activated in those who were in the placebo group–evidence that the drug was tamping down the brain’s response to social rebuffs.

It’s easier to make difficult decisions

Ever had to make a tough choice? For example, maybe you were torn between two health insurance policies. Or, perhaps, you were trying to sell your car, but you weren’t getting any offers at the price you asked, so you had to decide whether to cut your asking price or wait for a buyer who’d meet your original request. Believe it or not, taking an acetaminophen can impact the decision you make.

In a 2015 study in the Journal of Experimental Social Psychology, researchers using two experiments with volunteers who took 1,000 mg. of acetaminophen or a placebo discovered that the drug reduces the emotional pain of difficult decisions, making you feel less negatively about a choice you rejected (such as opting for a health insurance policy that only covered emergency care) and more willing to accept loss (such as a lower price for your car) when making your decision.

In addition, the researchers speculate that acetaminophen’s emotional pain-blunting effect may also extend to the checkout counter, making you willing to pay more since parting with your cash would “hurt” less.

You fear death less and are less confused by abstract art

You know how it is–when someone you know passes away or you hear news about someone’s death, it can trigger somber or anxious thoughts of your own inevitable demise and have you questioning the meaning of your life, a condition called “existential angst”. While it sounds strange, it turns out that taking acetaminophen can reduce these uneasy feelings, according to a 2013 study in the journal Psychological Science that was led by some members of the research team who conducted the “Go or No Go” study. As the study authors explain it, acetaminophen appears to block the brain signal that’s telling you something is wrong, so you feel less dread.

Interestingly, the same study found that acetaminophen can also make you less disturbed by movies, paintings and other scenes that are surreal, abstract, confusing or surprising, making them easier to accept.

Note: While it’s intriguing to uncover new and unexpected ways that acetaminophen can affect you when using it to treat pain, taking this drug solely to moderate your moods or behavior is risky since long-term use and/or taking more than the recommended single and daily dosages can cause serious injury, such as liver damage and death. Visit MedlinePlus for more information about acetaminophen and how to use it safely.

[Photo: Tonystl]