Correlates and consequences of opioid misuse trajectories among high-risk prescription drug users

Background: Prescription drug misuse is most prevalent among young adults aged 18-25, and opioids are the most frequently misused class of prescription drug among youth. Longitudinal research indicates that youth attenuate, maintain, or escalate opioid misuse over time, suggesting that misuse follows different temporal trajectories. However, no studies have articulated trajectories of opioid misuse among youth that include both duration of use and other indicators of escalated opioid use. Methods: 596 young adults age 16-25 who had misused one or more prescription drugs at least 3 times in the last 90 days were interviewed in Los Angeles and New York between October 2009 and March 2011. Latent class analysis on a subsample of opioid misusers (N=575) described opioid misuse trajectories based on years of use and indicators of misuse and drug form alteration within the past 12 months, 3 months, and 30 days. Results: The best-fitting solution yielded four latent classes: “intensive” (consistent high use), “active” (slight 3-month declines), “reduced” (recent use but no recent form alteration), and “limited” (3-month cessation). Latent classes differentially predicted the likelihood of heroin use, tranquilizer misuse, daily opioid use, and opioid withdrawal. Using latent class regression, socio-demographic variables, housing status, prescription history, and parental drug use were significantly associated with opioid misuse trajectories. Conclusions: Youth who misuse prescription opioids show different trajectories of historical and recent use. Data on decisions to use and alter a drug's form can be combined to describe patterns of misuse over time and predict important risk outcomes.