Exploring the latent trait of opioid use disorder criteria among frequent nonmedical prescription opioid users

Background: There is a need to explore the dimensional and categorical phenotypes of criteria of opioid use disorder among frequent nonmedical users of prescription opioids (NMUPO) users. Methods: We used pooled data of 2011-2012 National Survey on Drug Use and Health to examine reliability and phenotypic variability in the diagnosis of OUD secondary to NMUPO in a nationally-representative sample of 18+ years-old frequent past-year NMUPO users (120+ days, n = 806). Through exploratory factor analysis (EFA) and latent class analysis (LCA), we examined 10 past-year OUD criteria. We examined associations between the latent classes and sociodemographic/psychiatric/NMUPO correlates. Results: OUD criteria were unidimensional, and a three-class model was the overall best fitting solution for characterizing individuals into phenotypes along this unidimensional continuum: a "non-symptomatic class" (40.7%), "Tolerance-Time spent class" (29.0%) with high probability of endorsing Tolerance/Time Spent criteria, and a "High-moderate symptomatic class" (30.1%). The last class was significantly associated with being male, having insurance and obtaining prescription opioids (PO) nonmedically via "doctor shopping" as compared to the non-symptomatic class. "Tolerance-Time spent class" was significantly associated with being younger (18-25 years) and obtaining PO nonmedically from family/friends as compared to the non-symptomatic class. Conclusion: This study revealed the different characteristics and routes of access to PO of different classes of frequent NMUPO users. It is possible that these groups may respond to different interventions, however such conclusions would require a clinical study.