WASHINGTON (Reuters) - About a fifth of U.S. college students are taking painkilling pills and other prescription drugs to get high, a study published on Monday showed.

File photo illustration of pills of all kinds, shapes and colors, March 2003. REUTERS/Jacky Naegelen

And students who take prescription drugs for non-medical reasons are at least five times more likely to meet the definition of having a drug abuse problem than students not misusing them, the researchers reported in the journal Archives of Pediatrics & Adolescent Medicine.

The findings by researchers at the University of Michigan were based on a survey of 3,639 U.S. college students whose average age was just under 20.

“It’s very easy to get addicted,” Carol Boyd of the University of Michigan’s Substance Abuse Research Center, who helped conduct the study, said in a telephone interview.

“They perceive prescription medications as safer than street drugs such as cocaine and heroin despite the fact that the stimulants and the opioids (painkillers) are just like cocaine and heroin. And they’re very easy for them to get,” Boyd added.

Students were asked if they had taken four types of prescription drugs: opioids; stimulants; sleeping pills; and sedative or anti-anxiety pills.

About 60 percent said they had used such drugs with a prescription for medical reasons, while 20 percent said they had taken such drugs for non-medical reasons.

The students also were asked whether they had done anything illegal to get drugs, whether they had blackouts due to drug use, felt guilty about drug use, or felt sick after stopping taking the drugs.

If they answered yes for three or more of the 10 questions on the screening test, they were classified as having a drug abuse problem.

“A typical scenario that we hear from our focus groups and our students is: they go to the dentist to have their wisdom teeth taken out, and the dentist gives them 30 Vicodin (a powerful painkiller) and a refill,” Boyd said.

Many use the pills to manage the pain after the procedure then get rid of the unused ones when they are no longer needed, she said. But others keep them and use them to get high.

The findings are the latest evidence of an ongoing problem involving abuse of prescription drugs by U.S. young people.

A December report, also by University of Michigan researchers, showed that while overall use of illicit drugs by U.S. teenagers dropped in the past decade, abuse of prescription medications has not. Fifteen percent of 12th graders reported using a prescription drug for non-medical reasons in the prior year, that report found.

“It is the major emerging problem among teens,” said Sean Clarkin of the advocacy group Partnership For a Drug-Free America, who was not involved in the new study. “Their perceptions of the risks involved are pretty low.”