If you're a Botox user you're basically a zombie who's devoid of all emotion, according to new research. Talking to someone who uses Botox is sometimes tough, especially when you try to get a read on their expressions but can't get over the permanent look of shock on their face. But, in a bizarre twist, it goes both ways: The results of a study published in the journal Social Psychological and Personality Science have found that Botox patients can't understand your expressions, either.

NPR's Shots blog explains the background of the study, led by professors David Neal and Tanya Chartrand of Duke University:

Neal and Chartrand say the subtle contraction of our facial muscles when we mirror a friend's happiness or woe generates a feedback signal to our brains. Those incoming signals from facial nerves help the brain interpret how the other person is feeling.

It's all part of neuroscientists' recent focus on so-called "mirror neurons" – the brain cells that give us the power to empathize (to "feel with") someone else.

Now how does that relate to Botox users? The researchers tested 31 women who use Botox or a derma filler to see how quickly they could judge what emotions were displayed in a series of images. And the Botox users scored poorly against derma filler patients, meaning "Botox patients' ability to make fast judgments about another person's emotions was blunted." In other words, injecting botulinum toxin into your face to temporarily paralyze your muscles might actually be harmful. Who knew?

[Women who don't actually understand each other, image via Getty]