In addition to the sharing of intravenous injection equipment, another major contribution of drug dependence to HIV risk involves the association of cocaine dependence with increased sexual HIV risk behavior. Little is known about decision-making processes contributing to sexual risk behavior, particularly in cocaine dependence. 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 delay discounting tasks use choice procedures to quantify the rate at which the value of a future reward decreases over time. Delay discounting has been shown to be widely relevant to drug dependence;primarily by studies showing that dependent individuals have higher discounting rates (i.e., are more impulsive, or value future consequences less) than non-dependent individuals. Recent evidence also suggests that delay-discounting tasks can predict who will be successful in achieving abstinence in drug treatment. The proposed research will examine the relationship between delay discounting and sexual HIV risk behaviors among cocaine-dependent individuals. Two groups of 57 cocaine-dependent individuals each, matched on relevant demographics, will be examined in a single research session: 1) those scoring high on HIV sexual risk behaviors, and 2) those scoring low on HIV sexual risk behaviors. Delay discounting will be extensively examined in a variety of outcome conditions (gains versus losses, multiple magnitudes, and using hypothetical and potentially real rewards) using procedures previously employed by the principal investigator. Because impulsivity is recognized to be a multifaceted construct, and in order to provide a comprehensive assessment of impulsivity in sexual risk behavior in cocaine dependence, the study will also include tasks thought to assess forms of impulsivity distinct from delay discounting, specifically, probability discounting (procedurally similar to delay discounting, but assessing sensitivity to uncertain rather than delayed outcomes), and the Barratt Impulsivity Scale-11, a questionnaire measure of impulsivity. If delay discounting were found to be relevant to sexual risk behavior, then it would provide a rich theoretical framework, informed by both human and nonhuman animal studies, from which to understand and prevent sexual risk behavior. Successful completion of this study will provide information of clinical relevance for HIV prevention efforts in cocaine dependent populations by identifying the decision-making processes contributing to sexual risk behavior. For example, sexual risk behavior involves evaluating both delayed and uncertain consequences, both positive and negative consequences, and both small and large consequences. Knowing which of these decision-making processes contributes to sexual risk behavior may help to inform HIV prevention efforts by indicating the most effective language for use in media campaigns, improving decision-making skills in the most relevant domain, and indicating self-control techniques for avoiding sexual risk behavior.

Public Health Relevance

A behavioral study in cocaine dependent individuals will be conducted comparing those scoring high in sexual HIV risk behavior versus those scoring low in sexual HIV risk behavior in order to evaluate the basic decision-making processes related to sexual HIV risk behavior. A variety of impulsivity and decision-making measures will be assessed in order to determine which decision-making process are most relevant to engaging in sexual HIV risk behavior. Because impulsivity associated with cocaine dependence is known to result in public health harms through sexual HIV risk behavior, this study will improve HIV prevention efforts within cocaine dependent individuals by determining which decision-making processes are most relevant to target in HIV prevention efforts.

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
Exploratory/Developmental Grants (R21)
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Biobehavioral Regulation, Learning and Ethology Study Section (BRLE)
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Lin, Yu
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Johns Hopkins University
Schools of Medicine
United States
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Johnson, Matthew W; Bruner, Natalie R; Johnson, Patrick S (2015) Cocaine dependent individuals discount future rewards more than future losses for both cocaine and monetary outcomes. Addict Behav 40:132-6
Bruner, Natalie R; Johnson, Matthew W (2014) Demand curves for hypothetical cocaine in cocaine-dependent individuals. Psychopharmacology (Berl) 231:889-97
Johnson, Matthew W; Bruner, Natalie R (2013) Test-retest reliability and gender differences in the sexual discounting task among cocaine-dependent individuals. Exp Clin Psychopharmacol 21:277-86
Johnson, Matthew W; Bruner, Natalie R (2012) The Sexual Discounting Task: HIV risk behavior and the discounting of delayed sexual rewards in cocaine dependence. Drug Alcohol Depend 123:15-21