Most people probably wouldn’t think to grab a knife when they’re in need of comfort, but for millions of Americans, especially adolescents and young adults, self-injury provides an escape. Non-suicidal self-injury, deliberate harm most commonly carried out by cutting or burning oneself, is rarely intended to cause death. Anger, emotional pain, or frustration may seem like obvious reasons for masochistic behavior, but according to a team of researchers from Maastricht University in the Netherlands, boredom may be another reason behind self-injury.

To test their theory, the team recruited 69 participants and placed each one in a room alone to watch one of three types of films. One third of the participants was coaxed into boredom by watching a monotonous, 83-second-long clip of a table tennis game repeatedly over the course of an hour. Meanwhile, the other two groups watched either an hour-long sad movie or a documentary, which served as the neutral, control experiment.

During the viewing, participants could give themselves an electric shock with varying levels of intensity. It turned out, participants who watched a boring film clip administered shocks more frequently and at a higher intensity, compared to participants who watched a neutral or sad film.

Participants reported their mental and physical health history after the viewing, and the results showed those with a history of non-suicidal self-injury administered more shocks during the first 15 minutes of the experiment, compared to participants without a history. Their findings, published in the journal Psychiatry Research , suggest that boredom instigated much of the self-harm. It’s possible, the researchers said, that participants wanted to distract themselves from the monotony of the video with self-harm instead of trying to cope with negative emotions associated with boredom.

“Self-injury has a paradoxical effect in that the pain self-inflicted actually sets off an endorphin rush, relieving the self-harmer from deep distress,” psychologist and psychoanalyst Dr. Deborah Serani wrote for Psychology Today. “Deliberately injuring one's self can be viewed as a method to communicate what cannot be spoken. With self-harm, the skin is the canvas and the cut, burn, or bruise is the paint that illustrates the picture. Most individuals who self-injure have difficulties with emotional expression.”

Each year, one in five females and one in seven males turn to self-harm for relief. Ninety percent of them begin doing so during their teen or pre-adolescent years. People who struggle to express themselves may turn to self-harm out of frustration, or as a substitute for communication. The cuts may also bring a momentary sense of calm, a release from the tension that’s causing the pain.

Self-harm can quickly become a bad habit. Someone who does it once may begin to hurt themselves every time they experience a flicker of pain, frustration, or anger, and it can quickly become an unhealthy coping mechanism. This is why boredom may also activate the wish to commit self-harm — someone who is bored isn’t being positively stimulated, which triggers their bad habit.

Conversely, the group who shocked themselves may have wanted to gain control over the experiment, which they had no control over. According to Mental Health America, people intentionally hurt themselves for various reasons, but feeling out of control is one of the more common triggers. Participants were not allowed to choose which movie to watch, so they may have felt helpless.

While experts in the field have known about the more conspicuous sources of self-harm, adding boredom to the list of motives may improve treatments for at-risk populations. For those who already recognize they have a problem, being aware of what triggers self-harm is key to prevention. “Become aware of what issues bend or break you,” Serani said. “Try to dilute your exposure to them, call upon others to help you move through them and remind yourself that you can emerge from triggers successfully.”

Source: Nederkoorn C, Vancleef L, Wilkenhoner A, Claes L, and Havermans RC. Self-inflicted pain out of boredom. Psychiatry Research. 2016.