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| Impulsivity as a Predicture of Future Drug Status: From Bench to Bedside |
| Monday, May 28, 2007 |
| 10:30 AM–11:50 AM |
| Ford C |
| Area: BPH; Domain: Basic Research |
| Chair: Jin Ho Yoon (University of Vermont) |
| Discussant: Jesse Dallery (University of Florida) |
| Abstract: A growing body of research has drawn links between impulsive choice and a variety of behavior problems, including drug use. Previous research has shown that current drug users make more impulsive choices than never- and ex-drug users on tasks involving discounting of delayed rewards. This finding does not reveal whether drug use alters impulsive choice, or whether impulsive choice precedes/predicts drug use. While data supporting the former have been found, the focus of the present symposium is on the latter hypothesis. Here, we present data from clinical trials and human and non-human laboratories showing that performance on an impulsive choice task does in fact predict future drug use. Our findings may have important implications for understanding the behavioral mechanisms underlying drug use and help design more effective drug-treatment plans. |
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| Impulsivity on an Adjusting Delay Task Predicts Vulnerability to Drug Abuse in Rats. |
| JENNIFER PERRY (University of Kentucky), Marilyn E. Carroll (University of Minnesota) |
| Abstract: Research in humans has suggested a relationship between drug abuse and impulsivity defined as the selection of a smaller-immediate reward over a larger-delayed reward. In the present experiments, we used male and female rats to explore the hypothesis that increased levels of impulsivity precede and predict enhanced vulnerability to drug abuse. Rats were selected for high or low levels of impulsivity based on performance on an adjusting-delay task. This task allowed rats access to 2 levers - a response on one lever yielded one 45 mg food pellet immediately; whereas, a response on the other yielded 3 pellets after an adjusting delay. The delay decreased following responses on the immediate lever, and it increased following responses on the delay lever. A mean adjusted delay (MAD) was calculated for each session, and rats were separated into low (LoI) and high (HiI) impulsive groups based on mean adjusted delays (MAD) that were calculated . Subsequently, acquisition of cocaine self-administration was examined, as well as maintenance, extinction, and reinstatement of drug-seeking behavior. Regardless of sex, HiI rats acquired self-administration faster than LoI rats. In maintenance and extinction, LoI females responded more on a cocaine-paired lever than HiI females; however, there were no HiI/LoI differences in males. Female HiI rats showed greater reinstatement of cocaine-seeking behavior than all other groups. These data support the hypothesis that impulsivity precedes drug abuse in some phases of addiction, and they suggest that sex may play a role in the relationship between impulsivity and drug abuse. |
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| Delay Discounting Predicts Choice to Smoke in a Laboratory Model of Abstinence Reinforcement. |
| BETHANY R. RAIFF (University of Florida), Jesse Dallery (University of Florida) |
| Abstract: Delay discounting may be related to relapse during abstinence reinforcement interventions for cigarette smoking, and a nicotine patch may attenuate increases in delay discounting. The present study assessed the relationship between delay discounting and smoking following nicotine deprivation in a laboratory model of abstinence reinforcement, and the effects of a nicotine patch on discounting and smoking. Smokers were randomly assigned to an active (14 mg) or placebo patch group (n=15 per group). In each of three sessions, following a 3hr deprivation period, participants completed a delay discounting task, mood, and craving measures, and finally engaged in a laboratory model of abstinence reinforcement. During the control session, money was delivered every 30s regardless of smoking ($12.80). During the low ($5.00 maximum) and high ($20.00 maximum) sessions, participants could earn a progressively increasing amount of money for each 30s puff-free period. The low and high conditions significantly increased latency to smoke and significantly decreased amount of smoking relative to control. The nicotine patch did not affect delay discounting or smoking, however individuals who smoked during the low and high conditions showed higher rates of discounting. The association between discounting and choice to smoke may have important implications regarding treatment success and failure. |
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| Delay Discounting Predicts Postpartum Relapse to Cigarette Smoking among Pregnant Women. |
| JIN HO YOON (University of Vermont), Stephen Higgins (University of Vermont) |
| Abstract: The present study examined if baseline delay discounting (DD) for hypothetical monetary rewards predicted smoking status at 6-months postpartum among women who discontinued smoking during pregnancy. Participants were 48 women (10.5 + 4.1 weeks gestational age at study entry) who participated in a clinical trial examining the use of incentives to prevent relapse. Discounting for hypothetical monetary rewards, smoking status, and other socio-demographic characteristics were examined at baseline with smoking status being periodically re-determined through 6-months postpartum. Greater baseline DD was significantly associated with being younger, less educated, and having a history of depression, but only baseline DD was a significant predictor of smoking status with greater discounting being associated with smoking at 6-months postpartum. The results extend the association of DD with risk for substance abuse to pregnant and recently postpartum cigarette smokers and, to our knowledge, provide the first demonstration of DD predicting treatment outcome. |
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