Date Approved


Embargo Period


Document Type


Degree Name

M.A. Clinical Psychology




College of Science & Mathematics


Kirby, Kimberly C.

Committee Member 1

Soreth, Michelle Ennis

Committee Member 2

Drossel, Claudia


behavioral economics, demand, prescription drugs, purchase task, substance use, young adults


College students--Drug use; Drug abuse; Stimulants


Clinical Psychology


Non-medical prescription stimulant use (NMPSU), such as using medications like Ritalin, Adderall, and Concerta without a prescription or at a higher dosage than prescribed, is a rising trend in American adults. Use is most prevalent among college age adults (18-25 years old). Survey research among experienced users has identified several reasons college students are engaging in NMPSU, including enhancement of cognitive, athletic, and social performance, but less is known about how the relative reinforcing value differs based on the reasons of use. Behavioral economic drug purchase tasks have been used to capture reinforcer strength and motivation related to use of prescription drugs and other substances. For this study, we developed the Functional Purchase Task to measure demand for stimulant-like drug effects. A sample of 116 students experienced with NMPSU were recruited from two universities. Descriptive results indicated the highest endorsed reasons for use corresponded with higher demand across multiple metrics. Mixed model comparison analysis demonstrated that while demand for stimulant medications does differ based on reason for use, individual preference is a better predictor for demand. These initial results support the importance of accounting for function of use when assessing reinforcer strength, and encourage adoption of a functional approach to future studies using hypothetical purchase task measures.