Role of delay discounting in driving HIV sexual risk behavior in cocaine abuse

描述(由申请人提供)：除了共用静脉注射设备外，药物滥用对艾滋病毒风险的一个主要贡献涉及可卡因滥用与艾滋病毒性行为和艾滋病毒感染的增加之间的联系。人们对导致性危险行为的决策过程知之甚少，特别是在可卡因滥用方面。与性风险行为潜在相关的决策过程是延迟折扣，这被认为是冲动的一个方面。延迟折扣指的是观察到延迟奖励会降低其主观价值，在实验室研究中，通常是通过偏好较小的较早奖励而不是较大的较晚奖励来指标化的。延迟折扣已被证明与药物滥用广泛相关，主要是通过研究表明，吸毒者比非滥用者有更高的折扣率(即更冲动，或更不看重未来的后果)。几项动物研究表明，即使在长期戒除可卡因之后，长期接触可卡因也会导致食物增强剂延迟折扣的长期增加(即更喜欢较早较小的食物，而不是较大的较晚食物)。在R21赠款下，首席调查员制定了一项新的任务，评估延迟性奖励的折扣(即性折扣)。这项任务使用了临床上相关的假设选择，即现在无保护措施的性行为和等待戴避孕套的性行为之间的选择，参照参与者判断为性欲的个人的照片。可卡因滥用者的初步数据表明，折扣性奖励与自我报告性风险行为相关，并遵循与人类和动物其他奖励折现相同的数学形式。此外，对性奖励的贴现对两种操纵很敏感。也就是说，参与者更倾向于立即进行无保护措施的性行为，以回应更令人向往的伴侣，以及被认为最不可能患上性传播疾病的伴侣。两项研究将系统地扩展这一研究路线，以确定可卡因滥用个人的性折扣与艾滋病毒性行为风险行为之间的关系。一项研究将测试可卡因滥用者是否比匹配的非吸毒者表现出更大的性折扣，以确定性折扣是否与可卡因滥用状况有关。第二项研究将对未寻求治疗的可卡因滥用者服用安慰剂和2剂口服可卡因，以确定可卡因中毒对性折扣的因果作用。总体而言，这些研究将开发并提供具有临床意义的数据，用于检查性危险行为的新的、有经验支持的工具。最终，这个项目的完成将增加我们对性行为艾滋病毒危险行为的了解，从而为艾滋病毒预防和教育工作提供信息。 公共卫生相关性：将进行两项研究，以了解导致吸食可卡因个人艾滋病毒高风险行为和艾滋病毒感染率的基本决策机制。更具体地说，这些研究将探索 对未来后果的贬值(称为延迟贴现)是导致HIV性行为风险的一个因素。由于已知与可卡因滥用相关的风险行为会通过性艾滋病毒风险行为导致公共健康损害，这些研究将通过确定哪些决策过程与风险行为最相关，来改善可卡因滥用个人的艾滋病毒预防和教育工作。

DESCRIPTION (provided by applicant): In addition to the sharing of intravenous injection equipment, a major contribution of drug abuse to HIV risk involves the association of cocaine abuse with increased HIV sexual risk behavior and HIV infection. Little is known about decision-making processes contributing to sexual risk behavior, particularly in cocaine abuse. A decision-making process of potential relevance to sexual risk behavior is delay discounting, which is considered an aspect of impulsivity. Delay discounting refers to the observation that delaying a reward reduces its subjective value, and is typically indexed in laboratory studies by preference for smaller sooner over larger later rewards. Delay discounting has been shown to be widely relevant to drug abuse, primarily by studies showing that drug-abusing individuals have higher discounting rates (i.e., are more impulsive, or value future consequences less) than non-abusing individuals. Several animal studies show that chronic exposure to cocaine causes long lasting increases in delay discounting for food reinforcers (i.e. preference for smaller sooner over larger later food), even after prolonged abstinence from cocaine. Under an R21 grant the principal investigator developed a novel task assessing the discounting of delayed sexual rewards (i.e., sexual discounting). The task uses clinically relevant hypothetical choices between unprotected sex now vs. waiting for sex with a condom, in reference to the photograph of an individual judged as sexually desirable by the participant. Preliminary data in cocaine-abusing individuals suggest that the discounting of sexual rewards correlates with self-report sexual risk behavior, and follows the same mathematical form characteristic of the discounting of other rewards in humans and animals. Furthermore, discounting of sexual rewards was sensitive to two manipulations. That is, participants were more likely to prefer immediate unprotected sex in response to more desirable partners, and in response to partners judged least likely to have a sexually transmitted disease. Two studies are proposed that will systematically extend this line of research to determine the relationship between sexual discounting and HIV sexual risk behavior among cocaine-abusing individuals. One study will test whether cocaine-abusing individuals show greater sexual discounting than matched control non-drug users to determine if sexual discounting relates to cocaine abuse status. The second study will administer placebo and 2 doses of oral cocaine to non-treatment seeking cocaine-abusing individuals to determine the causal role of cocaine intoxication on sexual discounting. Collectively, these studies will develop and provide clinically meaningful data on a new and empirically supported tool for examining sexual risk behavior. Ultimately, completion of this project will increase our understanding of sexual HIV risk behavior and therefore inform HIV prevention and education efforts. PUBLIC HEALTH RELEVANCE: Two studies will be conducted in order to understand the basic-decision making mechanisms that drive the high rates of HIV sexual risk behavior and HIV infection rates in cocaine-abusing individuals. More specifically, the studies will explore whether the devaluation of future consequences (called delay discounting) is a factor that underlies HIV sexual risk behavior. Because risk behavior associated with cocaine abuse is known to result in public health harms through sexual HIV risk behavior, these studies will improve HIV prevention and education efforts within cocaine-abusing individuals by determining which decision-making processes are most relevant to risk behavior.