Predicting first use of heroin from prescription opioid use subtypes: Insights from the Monitoring the Future longitudinal panel

Background: Only a small proportion of individuals who initiate nonmedical use of prescription opioids (NUPO) transition to heroin, suggesting that more nuanced aspects of NUPO may be better indicators of risk for escalating opioid use trajectories. This study leveraged panel data to identify NUPO typologies based on NUPO characteristics associated with opioid risk trajectories (route of administration, motives) and compared rates of heroin initiation at follow-up across typologies. Methods: Latent class analyses were run among respondents with no history of heroin use from the Monitoring the Future Panel Study (base year N=10,408) at modal ages 18, 19/20, 21/22, 23/24, and 25/26. Indicators included oral NUPO, nonoral NUPO, and NUPO motives to experiment, have a good time with friends, get high, escape problems, manage pain, relax, and sleep. Heroin initiation at follow-ups through modal age 29/30 was predicted from class membership. Results: No NUPO, self-medication (oral, manage pain), recreational (oral, nonoral, experiment, get high, have a good time with friends), and mixed-motive (all routes, all motives) classes emerged. Heroin initiation rates did not differ across no NUPO and self-medication classes; recreational and mixed-motives classes initiated heroin at higher rates than the other classes and comparable rates to each other. Non-NUPO drug use prior to heroin initiation was prevalent in recreational and mixed-motive classes. Conclusions: NUPO does not uniformly or uniquely increase risk for heroin initiation. Leveraging more nuanced indicators of risk for heroin use and targeting polysubstance use in addition to opioid-specific programming may enhance the efficacy of public health efforts.