THURSDAY, Dec. 24, 2009 (HealthDay News) -- Acetaminophen -- best known as Tylenol -- is usually taken to relieve physical pain, but a new study suggests that the over-the-counter drug may also help ease the psychological pain of rejection.
Researchers assigned 62 healthy college undergraduate students to one of two groups. One group took 1,000 milligrams of acetaminophen daily, while the others took a placebo. Every evening for three weeks, participants were asked to report to what degree they experienced social pain using the "Hurt Feelings Scale," a measure widely used by psychologists.
Those taking acetaminophen reported fewer hurt feelings and social pain over the course of the experiment, while there was no change in reports of hurt feelings among those taking the placebo.
In a second experiment, 25 healthy students were asked to take either 2,000 milligrams of acetaminophen daily or a placebo. After three weeks, participants played a computer game designed to simulate social rejection. (Participants played a virtual ball-tossing game with two unseen, fictitious players who at first appeared to be sharing the ball but later "rejected" the student by not throwing them the ball.)
Students underwent functional MRI while they were playing. When it became apparent they were being rejected, those who had been taking acetaminophen had reduced neural responses in the dorsal anterior cingulate cortex and anterior insula -- areas of the brain associated with the emotional response to pain -- compared to those on the placebo.
"When you experience something that is socially painful, your body is going to experience it in much the same way as it would experience physical pain," explained study author C. Nathan DeWall, an assistant professor of psychology at the University of Kentucky. "By numbing physical pain, you should numb people to social pain. And that's what we've found."
The researchers theorize that acetaminophen may work because areas of the brain that process physical and social pain overlap, and what works to dull one sort of pain may help dull the other.
"When people are snubbed, rejected or dumped, they describe it as feeling hurt, crushed or broken-hearted," DeWall said. "What these data show is it's not just a metaphor. There is strong evidence neurobiologically to support that."
The study will be published in an upcoming issue of the journal Psychological Science.
Researchers noted that levels of positive emotions remained stable during the first experiment involving the hurt feelings journals.
"We don't have any evidence acetaminophen makes people feel good or happy," DeWall said. "What we found was that acetaminophen does make things feel not as bad when you feel rejected."
And during the second experiment, despite differences in brain activity levels, participants reported similar levels of feelings of distress about the rejection.
That raises a question about the study, said Dr. Bernard Carroll, scientific director of the Pacific Behavioral Research Foundation in Carmel, Calif. If those taking the acetaminophen and those taking the placebo reported the same level of negative feelings about being rejected by their computer playmates, then the acetaminophen really didn't provide much in the way of psychological benefit.
Furthermore, it wasn't just the dorsal anterior cingulate cortex and anterior insula that showed differences in activity between the acetaminophen and the placebo groups. There were differences in many areas of the brain, which would indicate a generalized effect of the pain reliever rather than some specific impact on processing of pain-related emotions.
"My problem with the experiment is that they have shown a nominal statistical difference but they do not reveal the real-world importance," Carroll said.
Yet the concept that a single drug could work on both psychological and sensory pain isn't a new one, Carroll said. Before other drugs became available, depression and psychosis were sometimes treated with morphine or heroin, Carroll said.
So the question is, if you've recently been dumped, gotten divorced or have otherwise been snubbed, will acetaminophen help make the rejection sting less?
It's premature to recommend widespread use of over-the-counter pain relievers to get you through a break-up, DeWall said. Overuse of acetaminophen can cause liver failure and drinking alcohol while using the drug can raise the risk of overdose.
"We don't want our paper to be read as a widespread call to use acetaminophen to solve all your problems," DeWall said.
The American Academy of Family Physicians has more on emotional health.