It's likely that everyone knows somebody—or they were the person, or they still are the person—that hurts themselves. Self-harm, through self-inflicted burns, cuts, or other means, is surprisingly common, practiced by roughly 20 percent of women and 14 percent of men, says science journalist Carrie Arnold in a story for Aeon.
Most people have a strong aversion to deliberately injuring their bodies. But for some people, writes Arnold, an odd connection in human brains means that bodily injury provides a sort of temporary relief from emotional turmoil:
When it comes to sensing physical and emotional pain, our brains use the same two areas: the anterior insula, a small patch of neural real estate that’s part of the cerebral cortex behind each ear, and the anterior cingulate cortex, a hook-shaped piece of brain tissue towards the front of the brain. These are the areas in the brain that process pain, regardless of whether we’ve felt the sting of rejection or the sting of a bee.
Pain relievers also act on these two areas, regardless of whether someone is experiencing emotional or physical pain. A 2010 study in Psychological Science revealed that the pain relievers such as Tylenol or paracetamol (acetaminophen) helped to relieve the distress associated with social rejection and also decreased activity in the anterior insula and the anterior cingulate cortex. This doesn’t mean that Tylenol is the next Prozac, but it does show just how intertwined emotional and physical pain are in the brain.
People who self-harm, writes Arnold, have “learned that, while the pain peaks with self-injury, it then comes down the other side. The physical pain lessens – as does the emotional pain.”
That doesn't mean self-harm is a healthy way to combat emotional distress. It's often used by those who've suffered trauma or been the victim of bullying or other personal attacks, and the UK's National Health Service recommends people see a therapist to help them learn to understand and cope with the underlying distress. After all, self-harm can cause serious damage, or even death.
In Arnold's own experience with self-harm, through self-inflicted cutting, she found that the relief offered was only temporary:
The problem was that the embarrassment of cutting, the knowledge that these marks would become permanently tattooed into my skin, and the fears that someone would discover my secret, meant that any relief was short-lived. All too soon, I was feeling worse than before, leaving me vulnerable to repeat episodes of psychic pain, followed by even more cutting.
It's often difficult for people who don't self-harm to understand why anyone would. But knowing about this bit of neuroscience might help make self-harm a little less mysterious: whether it's a good idea to exploit it, the connection—the physical wiring of the brain that ties emotions to physical sensation—is real.