McCabe SE, et al. - Researchers investigated if sociodemographic characteristics, nonmedical use of prescription drugs (NMUPD) characteristics (eg, frequency), and other substance use could be related to sources of NMUPD involving anxiolytics, opioids, and stimulants. Using self-administered questionnaires, they surveyed a nationally representative sample of 18,549 US high school seniors (2009–2016). Past-year NMUPD was reported in approximately 11.0% of high school seniors (n=1,917). They identified five subgroups of NMUPD sources (friend/relative sources, friend/purchased sources, own leftover prescription, multiple sources, and other sources) by performing latent class analysis. As per evidence gained, there is an association of different NMUPD sources with different substance use behaviors. They recommend encouraging prescribers to check prescription monitoring programs and screen adolescents for substance use/misuse when prescribing controlled medications.