Measures of cocaine and monetary responding during choice sessions

• Published in: Drug and alcohol dependence 2014, Vol.139, p.164-168
• Main Authors: Greenwald, Mark K, Ledgerwood, David M, Lundahl, Leslie H, Steinmiller, Caren L
• Format: Article
• Language: English
• Subjects: Psychiatry
• ISSN: 0376-8716
• DOI: 10.1016/j.drugalcdep.2014.03.009

Abstract Background Contingency management (CM) treatment is effective for treating cocaine dependence but further mechanistic studies of its efficacy are warranted. This study aimed to determine whether: (a) higher vs. lower predictable money amounts ($3 vs. $1; analogs of standard voucher-based CM) increase cocaine demand elasticity; and (b) probabilistic amounts matched for expected value with the $3-predictable amount (50% chance of $6; 25% chance of $12; and 12.5% chance of $24; analogs of prize CM) similarly affect cocaine choice. Methods Each of 15 cocaine-dependent participants first completed a qualifying session to ensure that intranasal cocaine functioned as a reinforcer, then completed a 10-session, within-subject, randomized crossover study. During each of the 10 sessions, the participant responded on a progressive ratio schedule to earn units of cocaine (5-mg or 10-mg) and/or money (five monetary conditions above). Results During the reinforcement qualifying session (10-mg vs. 0-mg units; no money alternative), cocaine choice was high. The $3-predictable amount significantly decreased cocaine choice relative to both the $1-predictable amount and the qualifying session. Cocaine-choices in the probabilistic conditions were similar to the $3 predictable condition. Conclusions These findings indicate that CM interventions targeted at reducing cocaine self-administration are more likely to succeed with higher value non-drug reinforcement.