Other Momentary Substance Behaviors as Predictors of College Students' Prescription Drug Misuse in Daily Life: An Exploratory Study.

Background: Limited prior research to examine co-occurrence of prescription drug misuse with other substances among young adults has documented outcomes that are more problematic for those with higher rates of co-ingesting alcohol. There is a need to understand how college students in this period of heightened risk use other salient substances in moments of their prescription misuse in daily life.

Method: Young-adult college students who engaged in recent prescription misuse ( = 297) completed ecological momentary assessment (EMA) over a 28-day period, resulting in 23,578 reports. Multilevel modeling examined within-person associations between other momentary substance use (including alcohol, nicotine, energy drinks, and marijuana) and prescription misuse in daily life. Analyses accounted for between-person characteristics, having a current focal prescription, and effects of reporting over time. Participant sex was also explored as a moderator.

Results: In adjusted multilevel models, college students' momentary nicotine use and energy drink use each were associated with their greater likelihood of prescription misuse in daily life. In contrast, momentary marijuana use was linked with lower likelihood of misuse. Moderation results indicated that males (but not females) were less likely to engage in prescription misuse in moments of their alcohol use.

Conclusions: Drawing from data obtained using EMA, findings provide novel insights about the real-world associations between prescription drug misuse and other salient substance behaviors during a developmental period that is important for establishing later substance use and health.