Acetaminophen increases risk-taking, according to study

Originally published at:


Couldn’t it just be that those people need to pop a couple tylenols because they’re sore from all the risky stuff they’ve been doing?


Interesting but rather odd study. For instance, they apparently started right out with acetaminophen and haven’t apparently tested any other analgesics - not even aspirin (or other NSAIDS). So pain reduction in general isn’t accounted for. And computer balloon popping aside there are apparently no numbers supporting that they’ve completely excluded the opposite causality; that risk taking increases acetaminophen taking.

Another question for future research will be identifying the biological mechanisms responsible for these effects of acetaminophen. Like more conventional nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and aspirin, acetaminophen inhibits the production of prostaglandins in the brain ([Flower and Vane, 1972](javascript:;)). The administration of such drugs might provide insight into whether the prostaglandins are involved in risk judgments as well as which enzymes producing prostaglandins (cyclooxygenase 1 and cyclooxygenase 2) are greater contributors to the effect.


Once again a psych study that mis-states it’s results. Should say “Acetaminophen alters MEN’S performance in a series of completely stakes-less exercises that we have decided to corelate to risk-taking because that sounds cool”


I don’t get what you are saying here. That sounds like “aside from this study, they have no numbers supporting the results of this study”

On the other hand, the introduction cites a number of studies purporting to show other neurological effects of acetaminophen:

I did have the same thought that this might be an indirect effect: pain reduction in general leads to lower risk perception and possibly all of those other things, and they don’t mention if similar studies have been done with NSAIDs.

The other thing that stood out to me was that they did the study three times and got congruent results that also aligned with the previous work: treatment group had more risk tolerance than the control. However, the third study used a different balloon popping program, and both the control and treatment groups showed greater risk aversion relative to the previous two studies by an amount far greater than the drug related effect they were looking for. This is of course why we do controls but it also indicates that the effect is small relative to other factors such as the wording or presentation of the challenge.

Why do you say MEN’S? they report the participant report genders, and they are about even. Two studies had somewhat more men and one had somewhat more women and they all showed similar results. Over the three studies combined they had 276 men, 265 women, and a few no response or prefer not to say. They don’t report separate statistical significance for men vs. women, but I don’t see any reason to assume it is drastically different. A much more accurate criticism would be that the study shows “Acetaminophen alters 20 year old college student’s risk assessment”. The participants are ~75% white, but in a college setting it is likely that most of the participants of any race are from relatively privileged socioeconomic classes. So even if the effect persists if you measure in retirees or racial minorities, or non college-educated adults, the baseline shift could easily be much much greater than the shift due to acetaminophen.

They do discuss the low-stakes nature of the study, but they also cite research showing that if you put real money on the line vs. fake money as in this study it tends to exaggerate effects like this rather than erase them. That doesn’t guarantee it would in this case, but it isn’t like they swept this under the rug.

They also in one of the 3 studies asked the participants to rate their willingness to engage in behaviors widely perceived as risky such as skydiving. This only measures attitudes not actions, but again agrees with the other results.


And yet it still does absolutely nothing for my headaches.


You got me - I had read another article that only stated the male population, and did not bother to actually read the link article or ,of course, the actual paper.

As for the rest of it until they can get reproducibility in psychology studies above a coin flip, I have great skepticism of any study that is based on results that involve people taking a survey, performing a stakeless simulation exercise, or self-reporting.


So about 95% of all studies. Yeah, me too.


:white_check_mark: Got out of bed this morning.


correlation and causation?


I was about to offer a response similar to yours, but much less extensive. Since you covered the issue so well, I’ll only note that clicking through to the 2015 DeWall et al. study gives this in the abstract: “Neuroscientific evidence suggests common overlap between systems involved in physical pain and decision-making.” So this is not exactly an odd hypothesis to be testing. I’d guess they’re testing with acetaminophen because it’s so darn common (despite its hepatotoxicity).

Also, I’m not a statistician or a biosciences researcher, but the p-values they’re getting are below 0.05, which I have read is the threshold for significance; that is you want to come in under that 0.05.

I wouldn’t be surprised if the hypothesized effect exists. We already know that a wide variety of chemicals have significant impacts on decision making and risk-assessment. But I doubt it’s a very big effect, or people would be crushing and snorting Tylenol.

EDIT to add: I did some more clicking around, and Keaveney’s MA thesis is on this topic. Ellen Peters is pretty well published, and has a book out on innumeracy, so I suppose she would be reluctant to sign on to anything with sloppy statistical methods.

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How about rewriting the title as

“Untreated pain decreases risk-taking”


Acetaminophen itself causes permanent liver damage, with each and every dose - but hey, that’s a risk worth taking, right? Ibuprofen damages your kidneys and gut - but at least you’re not gonna take that risk, right? There’s money to be made in cures for cures, folks.

And I don’t say that under the influence of acetominophen - I’m cool with my indica, thanks.


This jives with some earlier stuff I’ve read about acetaminophen reducing empathy. Weird stuff.–%20a%20potent%20physical%20painkiller,to%20emotional%20awareness%20and%20motivation.

Think outside the box.

I can’t. I have a headache.

Boom! Problem solved.

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Came in here to break down why this is yet another crappy study that shouldn’t even be getting press, but the BB commentariat is all over it already. Great job everyone.

Small sample size, overpowered conclusion from underpowered study, evidence of p-hacking, no evidence of mechanism, effect size within noise bars, poor controls, the list goes on. This paper has it all. Yet CNN is going to report it breathlessly and the world gets a little stupider. This is why we can’t have nice things.


I sometimes vaguely wonder how science stories like this (low stakes and importance, but zany headline potential) get surfaced in the first place. CNN doesn’t have someone reviewing every minor journal in every field; do universities have PR people forwarding this stuff? Do researchers do it themselves?

Sadly this is a lot of the problem, yup. The need to drive fundraising incentivizes all sorts of bad faith attempts to get press. One of many reasons we should be properly funding research with public funds. It’s a no-brainer return on investment, yet we starve these institutions and drive them to shenanigans to keep the lights on. Unless they have a football team, I guess.


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