1. Exploring the latent trait of opioid use disorder criteria among frequent nonmedical prescription opioid users Castaldelli-Maia, Joao Mauricio; Andrade, Laura H.; Keyes, Katherine M.; Cerdá, Magdalena; Pilowsky, Daniel J.; Martins, Silvia S. 2016 Articles OpioidsOpioid abuseEpidemiologyMedication abuseDrug abuseDrug abuse--EpidemiologySubstance abuseSubstance abuse--Epidemiology