Heroin and cocaine abusers have higher discount rates for delayed rewards than alcoholics or non-drug-using controls
Article first published online: 13 FEB 2004
Volume 99, Issue 4, pages 461–471, April 2004
How to Cite
Kirby, K. N. and Petry, N. M. (2004), Heroin and cocaine abusers have higher discount rates for delayed rewards than alcoholics or non-drug-using controls. Addiction, 99: 461–471. doi: 10.1111/j.1360-0443.2003.00669.x
- Issue published online: 13 FEB 2004
- Article first published online: 13 FEB 2004
- Submitted 16 May 2003; initial review completed 19 August 2003; final version accepted 16 October 2003
- discount rates;
- hyperbolic discounting;
- substance abuse
Aims To test a prediction of the discounting model of impulsiveness that discount rates would be positively associated with addiction. The delay-discount rate refers to the rate of reduction in the present value of a future reward as the delay to that reward increases.
Design and measurements We estimated participants’ discount rates on the basis of their pattern of choices between smaller immediate rewards ($11–80) and larger, delayed rewards ($25–85; at delays from 1 week to 6 months) in a questionnaire format. Participants had a one-in-six chance of winning a reward that they chose on one randomly selected trial.
Participants and setting Heroin (n = 27), cocaine (n = 41) and alcohol (n = 33) abusers and non-drug-using controls (n = 44) were recruited from advertisements. They were tested in a drug abuse research clinic at a medical school.
Findings On average, the cocaine and heroin groups had higher rates than controls (both P < 0.001), but alcoholics did not (P = 0.44). Abstinence was associated with lower rates for heroin abusers (P = 0.03), but not for cocaine or alcohol abusers (both P > 0.50).
Conclusions These data suggest that discount rates vary with the preferred drug of abuse, and that high discount rates should be considered in the development of substance abuse prevention and treatment efforts.