Botox injections are the most common cosmetic surgeries performed in the United States, with over 4.6 million people every year being injected with the botulinum toxin in order to paralyze facial muscles and prevent wrinkles. But botox doesn't just make people look younger (or, if done poorly, like a lion) - it might actually force its patients to stop feeling angry or sad, even if they don't want to.
The ever delightful NCBI ROFL has the scoop. Here's the paper, which comes from a 2008 issue of the Journal of the American Academy of Dermatology:
"The facial feedback hypothesis suggests that muscular manipulations which result in more positive facial expressions may lead to more positive emotional states in affected individuals. In this essay, we hypothesize that the injection of botulinum toxin for upper face dynamic creases might induce positive emotional states by reducing the ability to frown and create other negative facial expressions."
It's actually a simple enough idea - just as our emotions influence our facial expressions, our expressions can actually loop back and subtly influence our emotion. And if your face is so full of paralyzing bacteria that your mouth is stuck in a frozen smile...well, who wouldn't start feeling good eventually? At the very least, botox can repress negative emotions, as the researchers explain:
The use of botulinum toxin to pharmacologically alter upper face muscular expressiveness may curtail the appearance of negative emotions, most notably anger, but also fear and sadness. This occurs via the relaxation of the corrugator supercilii and the procerus, which are responsible for brow furrowing, and to a lesser extent, because of the relaxation of the frontalis.
But the face isn't just too paralyzed to feel pain. It's also apparently too stiff to feel true happiness:
Concurrently, botulinum toxin may dampen some positive expressions like the true smile, which requires activity of the orbicularis oculi, a muscle also relaxed after toxin injections.
Still, if you're worried botox will mean an end of happiness entirely, fear not! As the researchers so reassuringly put it, botox generally means a net decrease in negative emotions, which is pretty much the medical equivalent of being deliriously happy:
"On balance, the evidence suggests that botulinum toxin injections for upper face dynamic creases may reduce negative facial expressions more than they reduce positive facial expressions. Based on the facial feedback hypothesis, this net change in facial expression may potentially have the secondary effect of reducing the internal experience of negative emotions, thus making patients feel less angry, sad, and fearful."
Via NCBI ROFL.