Self-harm can include cutting yourself, burning yourself, banging your head, sticking hurtful objects into your body, or taking too many pills. While some people self-harm only once or twice and then abandon the behavior, others do it routinely. Now, a new study finds self-harming teens are more likely to develop emotional problems while also encountering difficulties at both school and work later in life.

"This is the first study to investigate outcomes amongst those with non-suicidal self-harm," Dr. Becky Mars, who led the research at Bristol University's School of Social and Community Medicine, told Medical Daily in an email. "We were quite surprised at just how high the risks were in relation to non-suicidal self-harm, given its high prevalence in the community."

To understand the frequency of self-harm among teens, the team of Bristol University researchers made use of the Avon Longitudinal Study of Parents and Children (ALSPAC), an ongoing birth cohort study. The team sent a detailed questionnaire on self-harm to 9,383 participants at age 16. It was returned by about 52 percent of participants with 4,810 participants completing the self-harm items. Those who returned the questionnaire were more likely to be female and white and to have a mother with higher education, higher income, and higher social class.

However, according to Mars, "there is no reason to believe that those individuals who returned the questionnaire were more likely to self-harm than those who didn't." In fact, Mars noted in her email to Medical Daily, "we have found that questionnaire non-responders have an increased risk of self-harm when compared with responders." Self-harm, Mars explained, is more common in females, those with negative mood symptoms, or those whose mothers reported negative mood symptoms when the child was age 11. While no differences have been found based on ethnicity, the behavior is also more common among those whose mothers perform manual labor.

While the questionnaire gathered data on mental health, substance use, education, and occupation, a prominent question focused on self-harm: “Have you ever hurt yourself on purpose in any way (for example, by taking an overdose of pills or by cutting yourself)?” To understand which participants had considered suicidal self-harm, the researchers asked two further questions: “On any of the occasions when you have hurt yourself on purpose, have you ever seriously wanted to kill yourself?” and “Do any of the following reasons help to explain why you hurt yourself on that (the most recent) occasion?” One response option to this second question is “I wanted to die.”

About 19 percent of the 16-year-olds who took part in the study had a history of self-harm, the researchers discovered, and most had not sought help from health professionals. Examining their progress over the next five years revealed even those who self-harmed without suicidal intent had an increased risk of developing mental health problems, including depression and anxiety, compared with their peers. They were also more likely to self-harm and to develop substance use problems — smoking and drinking too much or using illegal drugs.

However, the risks were generally stronger among the suicidal. They showed a higher risk of poor educational results and, five years later, were less likely to have progressed as far as their peers in education, training, or employment. While self-harm cannot be said to directly cause mental health problems or other difficulties, the researchers believe the study results indicate this behavior is a clear signal that all is not well.

"There is widespread lack of understanding amongst health and teaching professionals about those who self-harm without intending to take their lives,” said Dr. Becky Mars, who led the research at Bristol University's School of Social and Community Medicine. “It should not be dismissed or viewed as trivial, as it could be a warning sign for suicidal behavior or other problems later in life.

Source: Mars B, Heron J, Crane C, et al. Clinical and social outcomes of adolescent self harm: population based birth cohort study. BMJ. 2014.