The struggle to maintain accurate data on the prevalence of opioid abuse

In a new study published in the American Journal of Drug and Alcohol Abuse by researchers at New York University's Center for Drug Use and HIV Research (CDUHR), lead researcher Joseph J. Palamar, PhD, MPH and his team sought to describe differences in self-reporting of nonmedical opioid use among high school seniors, who were asked about both general nonmedical opioid use and also specifically about nonmedical Vicodin and OxyContin use.

The data was drawn from the Monitoring the Future (MTF) survey, a nationwide ongoing annual study of the behaviors, attitudes, and values of American secondary school students. The MTF survey is administered in approximately 130 public and private schools throughout 48 states in the US. Roughly 15,000 high school seniors are assessed annually.

The results were not always clear-cut.

"If someone checks off that they haven't used opioids you'd expect them to check off 'no' to nonmedical use of Vicodin and OxyContin later in the survey, but this wasn't always the case," said Dr. Palamar, who is also an assistant professor of Population Health at the NYU Langone Medical Center (NYULMC). "A lot of these teens reported that they've never used opioids in a nonmedical manner, but later on they report nonmedical Vicodin and/or OxyContin use."

The survey defines opioids as painkillers such as Vicodin and OxyContin for those taking the survey, but Dr. Palamar explains that "it is likely that a lot of teens either don't read the definition of opioid or simply don't pay attention."

In order to determine the prevalence and correlates of discordant self-reports of nonmedical use of opioids, the researchers' analyses utilized the responses collected from 31,149 high school seniors (12th graders) between 2009 and 2013. The students were first asked how many times they had taken narcotics other than heroin without a doctor's instruction in the past year. Later in the survey students were asked the same question twice more, once with regard to Vicodin and a second time for OxyContin.

In total, 8.3% (2,585) said they had engaged in nonmedical opioid use, 7.6% (2,365) had engaged in nonmedical Vicodin use and 4.4% (1,381) reported nonmedical use of OxyContin. However, 37.1% of those reporting nonmedical Vicodin use and 28.2% of those reporting nonmedical OxyContin use did not report overall nonmedical opioid use earlier on.

"When combining responses, we found the 8.3% figure to be an underestimate" said Dr. Palamar. "When factoring in the discordant responses, we believe that 11.1% would more accurately represent prevalence of past-year nonmedical opioid use among the high school seniors."

The results underscore that medical and law enforcement communities may be underestimating opioid use and not just among younger populations.

"Accurate data on the prevalence of nonmedical opioid use is crucial to informing prevention and interventions, especially when considering that heroin initiation can be the next step in the addiction progression," said Dr. Palamar. "We need to do a better job of identifying the scope of the problem in order to correctly assign and deploy resources to combat the unprecedented rise in drug overdose deaths, which are now the leading cause of injury death in the U.S."

Surveys administered via pencil and paper, such as MTF, provide a unique opportunity to examine underreporting, as there is no mechanism for preventing contradictory responses, note the researchers. Electronically administered surveys can employ such mechanisms, however, the study's researchers are more concerned with drug education than survey design.

"Teens in the U.S. require a better drug education," said Dr. Palamar. "We recently found that teens have been underreporting ecstasy use because many don't know that Molly is ecstasy, and now we found that many teens aren't aware that Vicodin and OxyContin are categorized as opioids, narcotics, or painkillers."

The researchers feel that better drug education with honest information may be key to preventing future drug epidemics.