Trajectories of prescription drug misuse during the transition from late adolescence into adulthood in the USA: a national longitudinal multicohort study.

backgroundPrescription drug misuse is most prevalent during young adulthood (ages 18-25 years). We aimed to identify prescription drug misuse trajectories for three drug classes (opioids, stimulants, and sedatives or tranquilisers) from adolescence into adulthood, assess the extent to which different trajectories are associated with symptoms of substance use disorder, and identity factors associated with high-risk prescription drug misuse trajectories.

methodsFor this longitudinal multicohort study, nationally representative probability samples of 51 223 adolescents in the USA were followed up across eight waves from age 18 years (cohorts 1976-96) to age 35 years. Data were collected via self-administered paper questionnaires.

findingsFive prescription drug misuse trajectories were identified and the defining characteristic that differentiated the five trajectories was the age when past-year prescription drug misuse high frequency peaked: rare or no misuse at any age, peak at age 18 years, peak at ages 19-20 years, peak at age 23-24 years, and peak at ages 27-28 years. Similar prescription drug misuse trajectories were identified for each prescription drug class. The later peak misuse trajectory for sedatives and tranquilisers crested at an older age (35 years) than that for the other drug classes. Prescription drug misuse trajectories were all associated with significantly greater odds of having two or more substance use disorder symptoms at age 35 years, especially the later peak trajectories. In controlled analyses, risk factors associated with the high-risk latest peak prescription drug misuse trajectory included high school heavy drinking, cigarette smoking, marijuana use, poly-prescription drug misuse, white race, and not completing a 4-year university degree.

interpretationPrescription drug misuse trajectories are heterogeneous, and any high-frequency prescription drug misuse is a strong risk factor for development of substance use disorders during adulthood, especially later-peak prescription drug misuse trajectories. These findings might help practitioners identify individuals at greatest risk for substance use disorders and target intervention strategies.

fundingNational Institute on Drug Abuse, National Institutes of Health.