I've been an ibuprofen girl for as long as I can remember. But pregnancy brings many changes, among them the mandate to avoid OTC painkillers other than acetaminophen. (I presume this is because acetaminophen acts on the Central Nervous System, protected by the blood-brain barrier, as opposed to the more ‘exposed' Peripheral Nervous System-but I'm not a doctor and my long list of banished items did not offer any explanations.)
After wrestling hopelessly against the tide of late-night leg pain the other evening, I went to the cabinet for some Tylenol. Drifting finally into a pain-free sleep, I noticed how oddly peaceful my mind had become. Attributing this to my newly acquired pain-free state rather than the analgesic, I went to bed and forgot about it.
Shortly thereafter, an issue of Psychological Science arrived on my doorstep, featuring a new study by fellow PT blogger Nathan DeWall, suggesting that acetaminophen can be used to treat social as well as physical pain. This intriguing new work builds on previous evidence that regions of the brain dealing with feelings of social rejection and physical pain overlap.
In Jaak Panksepp's 1998 book, Affective Neuroscience: The Foundations of Human and Animal Emotions, he theorized that given humans' long, uber-dependant infancies, a social attachment system that piggybacked onto the evolutionary physical pain system would promote survival. A 2003 study by Naomi Eisenberger using fMRI imaging showed that brain regions involving physical and social pain did indeed overlap. People often refer to the pain of social rejection with physical words like "heartbreak" and "hurt feelings," and it turns out those aren't just metaphors. The same acetaminophen that treats your headaches could also help soothe your broken heart.
The researchers gave participants a painkiller or placebo for three weeks and had them use a Hurt Feelings Scale to determine the extent of their social rejection for the day (amazing they didn't start with participants in junior high). The participants also gave measures of daily positive emotion to see if the pills might increase positive experience. The group getting the painkillers had a significant decrease in ‘hurt feelings,' but didn't show any difference in positive emotion.
Skeptical of self-report? The same study was repeated using fMRI imaging of blood flow activity in the brain, and got the same results. And the results of the replicated findings are encouraging. If the pain of social rejection can by soothed by acetaminophen, side effects of rejection - such as aggression and anti-social behavior - might be mitigated as well. The fMRI results showed that the pills reduced reactivity in regions linked to aggression, like the amygdala. This might explain why my Tylenol nightcap seemed to soothe more than just my achy joints. While scientists don't know how exactly the analgesics work (on social or physical pain for that matter), the effect seems to be centered in the ‘hurt feelings/social rejection' regions of the brain.
We've long known that social relationships are good for our health: People with more active friendships tend to live longer and suffer fewer health problems. Evolutionary overlaps linking physical and emotional/social reactions (i.e. physical and moral disgust, zygomaticus activity and humor assessments) are also nothing new. Surprisingly though, this was the first study to actively test what possibilities simple interventions like pain killers might have in these regions of overlap. The study of such interventions might lead to new possibilities for effective (and cheap) treatments of common social disorders. In fact, the researchers are presently working on one study suggesting that Tylenol reduces day-to-day carryover of social anxiety, and another examining whether Tylenol can boost self-esteem. Another new study led by George Slavich at UCLA shows that individuals with greater neural sensitivity to social rejection also experience more inflammation. Ironically, acetaminophen doesn't treat inflammation like ibuprofen does, but I'd love to see those researchers at a symposium discussing the collaborative potential of their findings.
It's tempting to race out to the nearest bar, set yourself up for an embarrassing social failure, and run back home to see if the Tylenol numbs the pain, but try to resist. Prolonged use of acetaminophen in high doses - or when mixed with alcohol - can cause liver damage, and the researchers caution against experimenting at home until more is known about the outcomes of off-label use.