Comparing Reported Prescription Drug Misuse between Ecological Momentary Assessment versus Timeline Follow-Back among College Students.

Background: Accurate assessment of prescription drug misuse (PDM) is critical among young-adult college students, a particularly high-risk group for this substance behavior. No studies have compared assessments of college students' reports of PDM obtained from their reporting in daily life (via ecological momentary assessment; EMA) to their retrospective accounts of PDM over the same period (via timeline follow-back interview; TLFB), an approach that is commonly used in substance use research. Purpose / Objectives: To determine day-level agreement and person-level agreement in college student reports of PDM in EMA versus TLFB methods. Methods: Participants were 297 college freshmen and sophomores (69% female) recruited based on misuse behavior in the past three months. PDM behaviors were captured in daily life using EMA for 28 days and TLFB administered during an in-person lab visit. Agreement was assessed at the person level (any PDM during the 28 days) and day level (PDM on a given day) using Cohen's kappa and percent agreement. Results: PDM was reported more frequently using TLFB compared to EMA. Person-level agreement between the two methods was good (k = 0.62, 95% CI: 0.53, 0.70), whereas day-level agreement was fair (k = 0.23, 95% CI: 0.19, 0.28). Agreement in stimulant misuse reported across methods was more consistent compared to reports of other medication classes. Conclusions: Findings offer implications for the assessment of college student PDM data in substance use research.