Teenagers who harm themselves are more likely to develop substance use problems later in life, compared with their peers who do not engage in self-harm, according to a new study.

Almost 5,000 16-year-olds participating in the study completed a questionnaire. They were asked whether they had ever hurt themselves on purpose in any way, such as by cutting themselves or taking too many pills. They were also asked if they had ever seriously wanted to kill themselves, Medical Daily reports.

“This is the first study to investigate outcomes amongst those with non-suicidal self-harm,” lead researcher Dr. Becky Mars of Bristol University in England, told Medical Daily. “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.”

The study found about 19 percent of the teens had a history of self-harm, and most had not sought professional help. The teens were followed for five years. Those who had a history of self-harm without suicidal intent were more likely to develop mental health problems, including depression and anxiety, than their peers. They were more likely to harm themselves and to develop substance use problems, the researchers report in the journal BMJ.

“There is widespread lack of understanding amongst health and teaching professionals about those who self-harm without intending to take their lives,” Mars said in a news release. “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.”