SECOND OPINION | Over-the-counter medicine could be affecting your mood

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You're probably reaching for them when you have a headache or when that old knee injury flares up. But over-the-counter pain relievers like ibuprofen and acetaminophen may be affecting your thoughts and emotions, too.

It's not the first time we've heard about this. Headlines about taking Tylenol for a broken heart have been capturing attention on the internet for a while. But a recent review of research on over-the-counter (OTC) analgesics provides some new insights into the unexplored potential of these common drugs to treat emotional pain, as well as some important reasons to exercise caution.

In part, it was concern about those headlines — and how they could affect use of these drugs — that prompted lead author Kyle Ratner to conduct a review of what scientists know so far.

"There had been several popular press articles about research on the topic," said Ratner, an assistant professor of psychological and brain sciences at the University of California Santa Barbara. "It's only been a handful of studies and because so many people take these drugs, before we jump to conclusions and make broad claims, we really need to be careful."

A few studies have shown that — at least in controlled, laboratory experiments — OTC analgesics can lessen hurt feelings, particularly the kind associated with social exclusion.

It's possible that how we were socialized to experience emotions could affect the way the drug influences us.- Kyle Ratner, professor

But one study of the effect of ibuprofen on social pain found that the treatment produced the opposite results in male and female participants. While women experienced less social pain after taking ibuprofen, men experienced more. The authors of that study postulated that the drugs may have disrupted the mens' default tendency to suppress emotional pain.

"It's possible that how we were socialized to experience emotions could affect the way the drug influences us," said Ratner. "The broader point is not assuming the drug is going to affect everyone the same way."

Caution against self-medicating

That's where reading just a headline or two could get you in trouble.

"If you think you're taking these drugs to dull something and you're getting an accentuating effect, that's problematic."

Research has also found that acetaminophen can reduce ability to empathize with others, as well as negatively affect performance on cognitive tests. Few of us want to be dumber and less caring versions of ourselves.

Ian Roberts, a postdoctoral fellow at University of Toronto who has conducted research on the effects of acetaminophen on volunteers who self-reported some features of borderline personality disorder, also cautioned that it's too soon to make treatment decisions based on his or other early inquiry into these uses for over-the-counter analgesics.

"I would strongly discourage anyone from using acetaminophen or any other OTC analgesic as treatment for emotional pain or distress," said Roberts.

Old drugs, new uses

"We really don't know what the effects would be in the longer term for folks who are interpersonally or emotionally sensitive … It's possible that self-medicating could have the opposite effect from what is intended."

Yet there are a lot of upsides to exploring new uses for old drugs.

"If you can repurpose old drugs that are used so well, where we have a good sense of toxicity issues and things like that, you can go through the research and development process faster," said Ratner. We already know that a huge swath of the population can tolerate these medications well. That's particularly helpful given that some psychiatric drugs have severe side effects.

Still, it's important to remember that overuse of acetaminophen can cause liver toxicity and is particularly dangerous when combined with alcohol, while taking too much ibuprofen can damage the lining of the stomach.

"It's not all harmless just because these are OTC drugs."

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