Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards (11-0) available immediately and larger rewards (25-5) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (Ainslie,...