Non-medical use of prescription opioids during the transition to adulthood: A multi-cohort national longitudinal study

Aims: To examine non-medical use of prescription opioids (NMUPO) patterns during the transition from adolescence to adulthood, and assess individual characteristics and other substance use behaviors associated with longitudinal patterns of NMUPO. Design: Nationally representative samples of high school seniors in the United States (wave 1: modal age 18 years) were followed longitudinally across three biennial follow-up waves (waves 2, 3 and 4: modal ages 19/20, 21/22 and 23/24 years). Setting: Data were collected via self-administered questionnaires to high school seniors and young adults. Participants: The longitudinal sample consisted of 27268 individuals in 30 cohorts (high school senior years 1976-2005) who participated in all four waves. Measurements: Self-reports of NMUPO and other substance use behaviors. Findings: Approximately 11.6% [95% confidence interval (CI)=11.2%, 12.0%] of the sample reported past-year NMUPO in at least one of the four waves. Among those who reported past-year NMUPO in at least one wave, 69.0% (67.6%, 70.4%), 20.5% (19.3%, 21.7%), 7.8% (7.1%, 8.6%) and 2.7% (2.3%, 3.1%) reported NMUPO at one, two, three and four waves, respectively. Several wave 1 variables were associated with greater odds of multiple waves of NMUPO and individuals who reported more waves of NMUPO had greater odds of other substance use behaviors. Conclusions: Although most non-medical use of prescription opioids among 18-year-olds in the United States appears to be non-continuing, approximately one-third of the sample reporting non-medical use of prescription opioids appear to continue use beyond age 18 and have elevated odds of other substance use behaviors at ages 23/24.