Over the last couple decades, more young people appear to be pulling out razor blades and lighters in order to injure themselves, according to anecdotal reports from counselors. Their intent is not to die, just to inflict harm, a behavior known as non-suicidal self-injury.

A recent study on the mental health of college students, presented in August at the American Psychological Association Meeting, found empirical evidence to document these observations. The results show that at one university, the rate of non-suicidal self-injury doubled from 1997 to 2007.

However, scientists aren't sure whether the behavior actually is becoming more rampant, or if they're simply detecting more cases due to increased awareness. And some researchers say that while there might have been an increase in the 1990s to early 2000s, it has likely hit a plateau by now. [See: Are More Kids Intentionally Hurting Themselves?]

Nonetheless, the widespread prevalence of non-suicidal self-injury does represent a public health concern. Several recent studies have found some 17-28 percent of teens and young adults say they have engaged in the behavior at some point in their lifetimes.

Scientists are now analyzing non-suicidal self-injury in an unprecedented way, trying to answer a number of questions, including: Why do people hurt themselves? Are some people hard-wired to self-injure? And what treatments work best to stop the cutting?

The consequences of the behavior go beyond physical harm and include depression, anxiety, social isolation and an increased risk for attempting suicide, said Peggy Andover, a psychology professor at Fordham University in New York.

"All of these negative consequences put together, coupled with the fact that this is such a highly prevalent behavior in our high schools, in our colleges, just in our community, it really highlights the fact that we really need to address this behavior," Andover said.

The "disorder" could also become official in the upcoming revision to the Diagnostic and Statistical Manual of Mental Disorders, or DSM, also known as the "Psychiatric Bible," due to arrive in 2013.

Suicide primer?

Non-suicidal self-injury is commonly defined by scientists as "deliberate discrete destruction of body tissue without the intent of suicide," said Kimberly Harrison, postdoctoral practitioner at Park Center Inc., a mental health treatment center in Fort Wayne, Ind. "You're trying to destroy your body in some way without trying to kill yourself," Harrison said.

A wide range of behaviors fit this description, including cutting, burning and carving of the skin to breaking bones, preventing wound healing and sticking yourself with pins and needles.

People usually start self-injuring in early adolescence, between the ages of 11 and 15.

Estimates for exactly how prevalent the behavior is in adolescents and young adults vary widely, from as low as 4 percent to as high as 38 percent.These estimates are mostly based on studies of small populations involving a few hundred people. But taken together, experts agree the percentage falls somewhere in the high teens to low 20s.

The most obvious harms from self-injury arise from the wounds themselves, which pose a risk of infection.But there are psychological consequences as well, including feeling shame about the behavior and fearing social rejection if the self-injurers do admit to hurting themselves.

There is also some evidence that people who engage in non-suicidal self-injury are at an increased risk of suicide, although the link is strongest among psychiatric patients. Researchers have speculated that self-injury might prime people for suicide in that they are able to overcome the fear and pain that comes from hurting themselves.

But "the vast majority of people who report non-suicidal self-injury are not trying to end their life, they're trying to cope with life," said Janis Whitlock, a researcher at Cornell University in Ithaca, N.Y., who recently published a review article on non-suicidal self-injury. "It's absolutely the opposite of what suicide is."

Like drugs and sex

Indeed, experts say most people engage in self-injury as a way to cope with their emotions, particularly negative ones. And most self-injurers report that it works – it calms them and brings a sense of relief.

These soothing feelings most likely result from the release of endorphins, brain chemicals that relieve pain and can produce euphoria.

"People use self-injury in a lot of ways that other people use drugs or alcohol, or food or sex…to try to feel better in the short run," Whitlock said.

People might also self-injure as a form of punishment.

Matthew Nock, a professor of psychology at Harvard University, has come up with four main reasons for engaging in self-injury, both personal and social. His model, which he recently discussed at the APA meeting, suggests that people self-injure to:

relieve tension or stop bad feelings;

feel something, even if it's pain;

communicate with others to show they are distressed;

get others to stop bothering them.

There is also evidence that people are more likely to self-injure if they have a negative body image coupled with strong negative emotions and poor coping skills.

"It makes it easier for them to harm the body," said Jennifer Muehlenkamp, a psychology professor at the University of Wisconsin-Eau Claire, who studies the condition.

A few studies also suggest biology is at play. For instance, research published in the July issue of the Journal of Affective Disorders found that non-suicidal self-injurers had lower levels of opioids in their bodies (endorphins are a type of opioid) than those who did not self-injure. One hypothesis is that people who self-injure have an opioid deficiency and do it to boost their natural opioid levels.

Recent research involving patients diagnosed with borderline personality disorder, a condition in which people often self-injure, found that self-injury could inhibit brain regions often involved in processing emotion.

Something about adolescence

Adolescence is a prime time for the behavior.

"From a developmental perspective, you've got a perfect storm for self-injury," said Whitlock, the Cornell researcher.

Not only do the young have to navigate a growing number of personal relationships, their brains and bodies are undergoing changes as well.

In early adolescence, part of the brain involved in emotion, the amygdala, and part of the brain involved in higher thinking, the cortex, are not fully connected, and as a result, they don't communicate as well as they do later in life.

"It's very common for adolescents, particularly early adolescents, to feel high levels of emotion and really not have many skills to deal with the emotion," Whitlock said.

When the children's brains are fully developed, they may learn other, more positive methods for coping with their emotions, such as talking to a friend, going for a run, or meditating. Self-injury does seem to be a behavior many adolescents grow out of, with around 80 percent reporting that they stopped injuring themselves within five years of starting, according to Whitlock's review, published in the May Issue of the journal PLoS Medicine.

From a practical point of view, self-injury is an easily accessible behavior for teens who might have a hard time getting a hold of drugs and alcohol.

Gender differences

Earlier research had suggested that self-injury is a more common behavior among girls, but recent studies show a more even split between the genders. A study of college students by Harrison, the Park Center scientist, found a higher rate of the behavior among males.

However, girls and boys might use different methods for hurting themselves.

For instance, a 2010 study by Andover, the professor at Fordham, found that girls are more likely to use cutting while boys are more likely to burn themselves. The researchers aren't certain the reason for the gender difference, but suggest it involves the idea that some injury methods are perceived as being more masculine, and others more feminine.

It's also unclear whether the genders differ in why they hurt themselves in the first place. For instance, it's possible males seek a display of physical toughness rather than a way to cope with emotions. However, much more research is needed in this area.

Lack of treatment options

There are no specific treatments for non-suicidal self-injury, although a technique known as dialectical behavioral therapy, used for borderline personality disorder, has been employed with some success.

"It's very, very intensive treatment," Andover said, and may not be appropriate for everyone with non-suicidal self-injury.

The majority of self-injurers likely overcome the behavior without seeking treatment, Muehlenkamp said, but treatment for these individuals might still be helpful.

"Anyone who's engaged in self-injury, even if it's one time in their life, they still report many more difficulties in their life, psychologically [and] socially," she said. "So even if you have someone who's self- injured one time, it may not be a bad idea for them to consider seeking some type of help."