Is nonmedical prescription opiate use a unique form of illicit drug use?

Nonmedical prescription opiate (NMPO) use is of great concern because of its high addiction potential, cognitive impairment effects, and other adverse consequences (e.g., hormonal and immune system effects, hyperalgesia and overdose). Due to the combination of drugs used by those who are NMPO users, it is difficult to isolate the negative effects of NMPO use from the effects of other legal and illicit drugs. Based on a stage model of substance use, this study tested whether NMPO use represents a unique form of illicit drug use among emerging adults and whether there are unique consequences of early NMPO use. We used longitudinal data from 912 emerging adults from the Raising Healthy Children study who were interviewed at least annually from the first or second grade through age 21. The findings indicated that almost all NMPO users have also used marijuana and a large majority has also used other drugs, such as cocaine and ecstasy. In addition, more frequent users of NMPOs are also more frequent users of other drugs. Except for violent behavior, NMPO use explained little unique variance in negative outcomes of use (e.g., drug use disorder, mood disorder, nonproductive behavior, poor health, and property crime) beyond that explained by other illicit drug use. Future studies examining the predictors or consequences of NMPO use and nonmedical use of other prescription drugs need to consider use within the context of other drug use.