Most teens who misuse prescription opioids are seeking pain relief, a new study concludes. University of Michigan researchers found four out of five teens who misused opioids said they did so to relieve pain.

Thirty percent of teens who did not take their medication as directed, and 47 percent of those who used another person’s prescription, were also motivated by other reasons, such as wanting to get high.

The study of 3,000 teens found teenage girls were almost twice as likely as boys to have misused prescription painkillers in the past year, HealthDay reports. The researchers did not find a gender difference in teens’ reasons for taking the drugs.

The study, published in The Journal of Pain, found black teens were more likely than white teens to misuse their prescriptions. Three-fourths of black teens who misused their prescriptions said they did so to relieve pain. “The authors noted that racial differences observed in this study could be related to inadequate pain management, poor communication, insufficient opioid availability, and under prescribing among black patients,” a journal news release notes.

Teens who misused their medications for reasons other than pain relief were more likely to divert their medications. The researchers said their findings indicate a need for close monitoring of opioids among teens.