Contingency management voucher redemption as an indicator of delayed gratification

This prospective analysis tested whether frequency of voucher redemptions during a contingency management (CM) substance use intervention was significantly associated with participants' ongoing substance use. Homeless, substance-dependent men who have sex with men (N = 131) were randomized into either a "full" or "lite" voucher-based CM intervention. All participants earned vouchers for attendance and participation; participants in the CM-full condition also received vouchers for substance abstinence and enactment of prosocial and/or health-promoting behaviors. Multivariate longitudinal negative binomial regression analyses (n = 118) assessed the association between substance use during the intervention and frequency of voucher redemptions. Participants who used methamphetamine (IRR = 0.66; 95% CI = 0.44-0.99) and/or opiates (IRA = 0.60; 95% CI = 0.40-0.99) during the intervention exhibited less time between voucher redemptions than individuals who achieved abstinence from these substances. Voucher redemption logs can be cost-effective and unobtrusive tools for measuring study participants' tendency to delay gratification. (C) 2014 Elsevier Inc. All rights reserved.