Nonmedical use of prescription stimulants during college: four-year trends in exposure opportunity, use, motives, and sources.

OBJECTIVE Examine trends in nonmedical use of prescription stimulants (NPS), including motives, routes of administration, sources, cost, and risk factors. PARTICIPANTS 1,253 college students. METHODS Data were collected annually during academic years 2004-2005 through 2008-2009. Generalized estimating equations analyses evaluated longitudinal trends. Logistic regression models evaluated stability of associations between risk factors and NPS over time. RESULTS Almost two-thirds (61.8%(wt)) were offered prescription stimulants for nonmedical use by Year 4, and 31.0%(wt) used. Studying was the predominant motive (73.8% to 91.5% annually), intranasal administration was modest (< 17% annually), and the most common source was a friend with a prescription (≥ 73.9% annually). Significant changes over time included decreasing curiosity motives, increasing overuse of one's own prescription, and increasing proportion paying $5+ per pill. Lower grade point average and alcohol/cannabis use disorders were consistently associated with NPS, holding constant other factors. CONCLUSIONS Prevention opportunities exist for parents, physicians, and college administrators to reduce NPS.