IMPULSIVITY IN DRUG DEPENDENCE--DELAY DISCOUNTING

理解药物依赖可能需要对药物依赖者典型表现出的冲动和失控行为进行科学研究。冲动性被定义为选择较小的更直接的奖励而不是较大的更延迟的奖励。失控是指对自我控制的决定或选择的偏好，在稍后的时间里，这种偏好会逆转，转而支持冲动的选择。理解冲动和失控的一种方法是研究延迟奖励是如何贴现的。然而，延迟奖励的折扣很少在药物依赖个体中进行研究。在这个新的应用中，我们将系统地探索药物依赖的各种潜在结果的延迟贴现以及可能调节贴现过程的因素，包括艾滋病风险行为导致的健康结果的贴现。提出了两个系列的研究。系列一将包括五个实验。在这些实验中，我们将评估阿片类药物依赖（实验1）、可卡因依赖（实验2）、大麻依赖（实验3）、酒精依赖（实验4）和尼古丁依赖（实验5）的参与者与年龄、性别、智商、教育程度、吸烟状况（实验1-4）、军事状况和社会地位匹配的正常对照的延迟折扣。在每一项研究中，我们都将检验以下因素的延迟折扣（包括符号效应和偏好逆转）：(1)金钱，(2)主要依赖药物，以及(3)危险性行为导致的健康结果。系列二由四个实验组成，采用可能调节延迟折现的条件。实验6和7将考察药物戒断对阿片类药物依赖个体和尼古丁依赖个体延迟折扣行为的影响。实验8将检验酒精对尼古丁依赖个体延迟折扣的影响。此外，我们将在每个研究中使用冲动性的其他措施，并检查这些措施与延迟折扣的相关性。总的来说，这些建议的措施将提供对药物依赖者冲动的全面评估。此外，我们将评估艾滋病风险行为和渴望，以确定那些从事危险行为或报告毒品渴望的人是否也大大低估了未来。这些研究将提供关于药物依赖中明显的矛盾行为（失去控制和冲动）的系统信息，允许对不同类型药物依赖的这些行为进行比较，并提供可能导致参与艾滋病风险行为的过程的见解。

Understanding drug dependence may require the scientific investigation of the impulsive and loss of control behavior typically exhibited by the drug-dependent. Impulsivity has been defined as the selection of a smaller more immediate reward over a larger more delayed reward. Loss of control refers to a preference for the self-controlled decision or choice, that at a later time reverses in favor of the impulsive choice. One approach to understanding both impulsivity and loss of control is by examining how delayed rewards are discounted. The discounting of delayed rewards, however, has only been rarely studied in drug-dependent individuals. In this new application, we will systematically explore the delay discounting of a variety of potential outcomes in the drug dependent and the factors that may modulate the discounting process including the discounting of health outcomes that result from AIDS-risk behavior. Two series of studies are proposed. Series One will consist of five experiments. In these experiments, we will assess delay discounting in opioid-dependent (Experiment 1), cocaine-dependent (Experiment 2), marijuana dependent (Experiment 3), alcohol-dependent (Experiment 4), and nicotine-dependent (Experiment 5) participants vs normal controls matched on age, sex, IQ, education, smoking status (for Exp 1-4), martial status, and SES. In each of these studies, we will examine the delay discounting (including sign effect and preference reversals) of (1) money, (2) primary drug of dependence, and (3) health outcomes that result from risky sexual behavior. Series Two, which is composed of four experiments, employs conditions that may modulate delay discounting. Experiment 6 and 7 will examine the effects of drug withdrawal on the delay discounting behavior of opioid- and nicotine-dependent individuals. Experiment 8 will examine the effects of alcohol administration on delay discounting in nicotine-dependent individuals. Moreover, we will use other measures of impulsivity in each study and examine the correlation of these measures with delay discounting. Collectively, these proposed measures will provide a comprehensive assessment of impulsivity in the drug- dependent. Also, we will assess AIDS-risk behavior and craving to determine whether those that engage in risky behavior, or report the drug cravings also drastically discount the future. These studies will provide systematic information about the paradoxical behavior (loss of control and impulsivity) evident in the drug-dependent, permit comparisons of these behaviors across types of drug dependence, and provide insight into the processes that may lead to engaging in AIDS-risk behavior.