Discordant reporting of nonmedical opioid use in a nationally representative sample of US high school seniors

Background: Nonmedical opioid use has become a major public health concern due to increases in treatment admissions, overdoses, and deaths. Use has also been linked to heroin initiation. Reliable data on nonmedical opioid use are needed to continue to inform prevention. Objective: To determine the prevalence and correlates of discordant self-report of nonmedical use of opioids in a national sample. Methods: Utilizing a nationally representative sample of 31,149 American high school seniors in the Monitoring the Future study (2009-2013), discordant responses between self-reported 12-month nonmedical opioid use and self-reported 12-month nonmedical Vicodin and OxyContin use (reporting Vicodin/OxyContin use, but not reporting "opioid" use) were assessed. We also used multivariable logistic regression to determine the characteristics of students who were most likely to provide a discordant response. Results: 37.1% of those reporting nonmedical Vicodin use and 28.2% of those reporting nonmedical OxyContin use did not report overall nonmedical opioid use. Prevalence of nonmedical opioid use (8.3%) would increase when factoring in Vicodin, OxyContin, or both, by 2.8%, 1.3%, and 3.3%, respectively. Females were more likely to provide a discordant response to Vicodin and highly religious students were more likely to provide a discordant response regarding OxyContin use. Those who reported cocaine or nonmedical tranquilizer use were at consistently low odds for discordant responses. Nonmedical amphetamine users were at low odds for providing a discordant Vicodin response. Conclusion: Prevalence of nonmedical opioid use may be underreported on some surveys, particularly among specific subpopulations. Further research on the effect of question order and skip-patterns (e.g., "gate" questions) is needed. Reliable data on nonmedical opioid use are needed to continue to accurately inform prevention.