Delay Discounting in Drug Dependence

描述（由申请人提供）：延迟强化剂在药物依赖性中的折扣研究越来越多。这项研究的结果是一致的，反映了药物依赖的一个重要方面。具体来说，这些研究表明，依赖药物的个体比对照组更容易对金钱产生折扣。此外，药物依赖者对药物依赖的轻视程度超过对金钱的轻视程度。曾经依赖毒品的人或最近戒断毒品的人以目前依赖毒品的人与匹配对照者之间的比率折现，或以接近匹配对照者折现的比率折现。此外，加强戒断已被证明可以减少毒品依赖者对金钱和香烟的折扣。总的来说，这些研究表明药物依赖个体比对照组折扣更多，药物依赖个体之间的过度折扣可能是药物使用的可逆效应。在这一竞争的延续中，我们建议通过解决三个具体目标来继续这一富有成效的研究。第一个具体的目的是检查是否药物依赖的个体有合并症折扣延迟强化比个人没有合并症。实验1将通过比较阿片类药物依赖的吸烟者、阿片类药物依赖的非吸烟者、非阿片类药物依赖的吸烟者和非阿片类药物依赖的非吸烟匹配对照组的折扣来检查共病物质依赖障碍。Exp.2将检查吸烟者的非物质依赖共病精神障碍，即抑郁症。具体来说，我们将比较抑郁吸烟者、非抑郁吸烟者、抑郁非吸烟者和非抑郁非吸烟匹配对照的折扣。第二个具体目标是广泛比较吸烟者和非吸烟者的延迟折扣和概率折扣。先前的一项研究报告说，吸烟者和不吸烟者在概率折现上没有区别。前一份报告仅从一个量级考察了货币的贴现。Exp.3将通过检查和比较延迟和概率贴现，系统地复制和扩展先前的研究。具体来说，我们将把这两种类型的折扣与几种商品进行比较，每种商品在吸烟者和匹配对照组中都有不同的幅度。第三个具体目的是检验折扣和节制之间的关系。以前我们已经表明，戒烟者的折扣与不吸烟者没有什么不同。有两个假设可以解释这一观察结果：(a)成功戒烟的吸烟者在开始戒烟前的折扣更少（折扣更少导致戒烟）；(b)戒烟导致折扣更少。这些假设可能不是相互排斥的。在Exp.4中，我们将检验有近似戒烟计划的个体是否与没有近似戒烟计划的当前吸烟者和戒烟者的折扣不同。在Exp.5中，我们将继续我们最初关于强化禁欲对折扣的影响的观察。具体而言，我们建议通过实施和取消应急管理程序，在吸烟者中复制和扩展这一观察结果。如果我们之前的工作被复制，那么当戒烟得到加强时，折扣应该会减少。我们将通过确定当吸烟者复吸时折扣的减少是否会逆转来扩展这项工作。

DESCRIPTION (provided by applicant): The discounting of delayed reinforcers among the drug dependent has been increasingly studied. The results of that research are consistent and reflect an important dimension of drug dependence. Specifically, these studies have shown that drug-dependent individuals discount money more than matched controls. Moreover, drug-dependent participants discount their drug of dependence more than they discount money. Ex-dependent or recently abstinent drug users discount money either at a rate intermediate between current drug-dependent individuals and matched controls, or at a rate that approximates discounting of the matched controls. Furthermore, reinforcing abstinence has been shown to decrease the discounting of money and cigarettes in the drug dependent. Overall, these studies suggest that drug-dependent individuals discount more than controls and the excessive discounting among the drug dependent may be a reversible effect of drug use. In this competing continuation, we propose to continue this productive research by addressing three specific aims. The first specific aim is to examine whether drug-dependent individuals with co-morbidity discount delayed reinforcers more than individuals without that co-morbidity. Exp. 1 will examine co-morbid substance dependence disorder by comparing the discounting of opioid-dependent cigarette smokers, opioid-dependent non-smokers, non-opioid-dependent smokers, and non-opioid- dependent, non-smoking matched controls. Exp.2 will examine a non-substance dependence co-morbid psychiatric disorder among cigarette smokers, namely, depression. Specifically, we will compare the discounting of depressed smokers, non-depressed smokers, depressed non-smokers, and non-depressed, non-smoking matched controls. The second specific aim is to extensively compare delay and probability discounting in smokers and non-smokers. A prior study reported that smokers did not differ from non-smokers on probability discounting. That prior report examined the discounting of money at only one magnitude. Exp.3 will systematically replicate and extend that prior study by examining and comparing delay and probability discounting. Specifically, we will compare those two types of discounting with several commodities, each at several magnitudes, in both smokers and matched controls. The third specific aim is to examine the relationship between discounting and abstinence. Previously we have shown that ex-smokers do not discount differently than non-smokers. Two hypotheses to explain that observation are (a) smokers who are successfully abstinent discounted less prior to the initiation of abstinence (less discounting leads to abstinence) and (b) abstinence leads to less discounting. These hypotheses may not be mutually exclusive. In Exp.4, we will examine whether individuals with proximate plans to quit cigarette smoking discount differently than both current smokers with no proximate plans to quit and ex-smokers. In Exp.5, we will follow up our initial observation regarding the effects of reinforced abstinence on discounting. Specifically, we propose to replicate and extend that observation with cigarette smokers by imposing and removing a contingency management procedure. If our prior work is replicated, then discounting should decrease when smoking abstinence is reinforced. We will extend that work by determining whether the decrease in discounting reverses when cigarette smokers relapse.