High school students who legitimately use an opioid prescription are one-third more likely to abuse the drug by age 23 than those with no history of the prescription, according to a new University of Michigan study.

These teens abuse OxyContin, Vicodin and other prescription pain relievers to get high, relax or feel good after leaving high school despite their strong disapproval of marijuana use, U-M researchers say.

Their findings are timely in light of the recent U.S. Food and Drug Administration’s decision to approve use of OxyContin for children ages 11 to 16, they say.

Somewhat counterintuitive, the risk is concentrated among adolescents who have little or no history of illegal drug use and who strongly disapprove of drug abuse. It may be explained in part by the novelty of drug use effects, since a prescription pain reliever is likely to be their initial experience with an addictive substance, the researchers say.

“Most likely, the initial experience of pain relief is pleasurable and this safe experience may reduce perceived danger,” said the study’s lead author Richard Miech, research professor at the U-M Institute for Social Research. “A pleasurable and safe initial experience with a drug is a central factor in theories of who goes on to misuse drugs.”

In contrast, among adolescents with more extensive drug experience, the legitimate use of a prescription pain reliever may be expected to make relatively less of an impression compared to other controlled substances they have used.

“Although these experienced individuals may go on to misuse prescription pain relievers, such misuse does not appear to result from an introduction to pain relievers through a legitimate prescription,” Miech said.

Data comes from the Monitoring the Future study, a nationally representative sample of 6,220 individuals surveyed in 12th grade and then followed up through ages 19-23. Participants indicated if they misused opioids in the last 12 months.

Parents may opt for non-opioid options as the initial treatment for minor painful conditions to lower their children’s risk for drug dependency. Pain relievers could be prescribed if non-opioid treatments are insufficient, the researchers say.

Miech and colleagues say the data does not have information on the dose, length or effectiveness for opioid prescriptions. In addition, teens who dropped out of high school by 12th grade — a segment previous research indicates has higher drug use levels — are not factored.

The study’s other authors were Lloyd Johnston, Patrick O’Malley, Katherine Keyes and Kennon Heard.

The findings appear in the current issue of Pediatrics.