Tylenol is a trade name for acetaminophen, a medication that has been used for over a hundred years to treat pain and fever. Unlike acetylsalicylic acid (aspirin) it does not affect blood clotting and can safely be used by people who are on “blood thinners.” Metabolism of acetaminophen occurs in the liver with its breakdown products being readily excreted. However, an overdose can result in exceeding the liver’s ability to safely eliminate metabolites and one of these, N-acetyl-p-benzoquinone imine, can damage the liver to the extent that a liver-transplant is needed. Consuming alcohol enhances the formation of the toxic metabolites and many cases of acetaminophen-induced liver damage occur when the drug and alcohol are consumed together.
While liver toxicity is the main concern with acetaminophen, researchers have also raised the possibility that the drug may affect the mind. In particular, a 2015 study by Ohio State University psychologists suggesting that acetaminophen blunts emotional processing caused a flurry of social media activity with some bloggers claiming “soul-deadening” effects. The term “soul” was never mentioned by the researchers and I have no idea whether we have one, and if we do, what sort of chemical brutality can dispense with it. I will leave those discussions to experts in the fields of philosophy or religious studies.
“Empathy,” on the other hand, I can grasp. It is the ability to place oneself in another’s position and understand what they are feeling. It is a prime quality in a physician, and is something we look for when interviewing medical school applicants. So, does the Ohio State study show that acetaminophen reduces empathy?
Researchers gave either acetaminophen or a placebo to subjects who were then shown pictures that were extremely unpleasant, moderately unpleasant, neutral, moderately pleasant or extremely pleasant drawn from “The International Affective Picture System (IAPS) which is a database of pictures designed to provide a standardized set of pictures for studying emotion and attention. For example, an unpleasant picture may portray malnourished children, a cow in a field would be neutral, and children playing with kittens would be deemed pleasant. After being shown an array of forty pictures, participants were then asked: “To what extent is this picture positive or negative using a scale ranging from -5 (extremely negative) to +5 (extremely positive).”
People who took acetaminophen had a somewhat smaller spread of reactions than those taking a placebo. This was interpreted as “blunting evaluations towards both pleasant and unpleasant stimuli.” I think that is quite a stretch, given that the differences were tiny. In the “extremely unpleasant” category, for example, the difference on the 5-point scale between the acetaminophen group and the placebo group was 0.2, hardly a difference with any practical significance. I doubt that a doctor who has swallowed a couple of acetaminophen tablets for a headache would be less empathetic towards patients, or that a teacher would be less understanding about a dog having eaten the homework.
The Ohio State researchers are not the only ones to have explored the effects of acetaminophen on the mind. In a University of British Columbia study subjects were asked to write essays about death and those who had taken acetaminophen “were more able to cope with worrisome ideas more than those who had been given a placebo.” Furthermore, when asked to pass judgement on hypothetical criminal activities, they were less strict. Hard to know what the practical significance here is. Perhaps during jury selection prosecuting attorneys should ask prospective jurors if they had been taking acetaminophen.
Basically, all of this is pretty soft science. Thinking about what it all means can give one a headache. For which acetaminophen will work.
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