Delay discounting is associated with treatment response among cocaine-dependent outpatients

Abstract

Delay discounting (DD) describes the rate at which reinforcers lose value as the temporal delay to their receipt increases. Steeper discounting has been positively associated with vulnerability to substance use disorders, including cocaine use disorders. In the present study, we examined whether DD of hypothetical monetary reinforcers is associated with the duration of cocaine abstinence achieved among cocaine-dependent outpatients. Participants were 36 adults who were participating in a randomized controlled trial examining the efficacy of voucher-based contingency management (CM) using low-magnitude (N = 18) or high-magnitude (N = 18) voucher monetary values. DD was associated with the number of continuous weeks of cocaine abstinence achieved, even after adjusting for treatment condition during the initial 12-week, t(33) = 2.48, p = .045 and entire recommended 24-week of treatment, t(33) = 2.40, p = .022. Participants who exhibited steeper discounting functions achieved shorter periods of abstinence in the Low-magnitude voucher condition (12-week: t(16) = 2.48, p = .025; 24-week: t(16) = 2.68, p = .017), but not in the High-magnitude voucher condition (12-week: t(16) = 0.51, p = .618; 24-week: t(16) = 1.08, p = .298), although the interaction between DD and treatment condition was not significant (12-week: t(32) = -1.12, p = .271; 24-week: t(32) = -0.37, p = .712). These results provide further evidence on associations between DD and treatment response and extend those observations to a new clinical population (i.e., cocaine-dependent outpatients), while also suggesting that a more intensive intervention like the High-magnitude CM condition may diminish this negative relationship between DD and treatment response.

(PsycINFO Database Record (c) 2011 APA, all rights reserved).

Figures

Figure 1

Best fit line representing the relationship between continuous weeks of abstinence and logarithmic ED50, which was evaluated at the mean of the indicator variable representing treatment for the entire sample during the 12-week voucher period (top panel) and 24-week treatment period (bottom panel). The ED50 value indicates the number of days that takes to lose 50% of the original objective value of a reinforcer, and is expressed as an inverted k (1/k). The greater the ED50 value, the greater the number of days needed for the reinforcer to lose 50% of its original objective value (i.e., low impulsivity).

Figure 2

Regression line between logarithmic ED50 and continuous weeks of abstinence in each treatment condition during the 12-week voucher period (top panel) and 24-week treatment period (bottom panel).