Alternative reinforcer response cost impacts cocaine choice in humans

Abstract

Cocaine use disorders are an unrelenting public health concern. Behavioral treatments reduce cocaine use by providing non-drug alternative reinforcers. The purpose of this human laboratory experiment was to determine how response cost for non-drug alternative reinforcers influenced cocaine choice. Seven cocaine-using, non-treatment-seeking subjects completed a crossover, double-blind protocol in which they first sampled doses of intranasal cocaine (5, 10, 20 or 30 mg) and completed a battery of subject-rated and physiological measures. Subjects then made eight discrete choices between the sampled dose and an alternative reinforce (US$0.25). The response cost to earn a cocaine dose was always a fixed ratio (FR) of 100 responses. The response cost for the alternative reinforcer varied across sessions (FR1, FR10, FR100, FR1000). Dose-related increases were observed for cocaine choice. Subjects made fewer drug choices when the FR requirements for the alternative reinforcers were lower than that for drug relative to when the FR requirements were equal to or higher than that for drug. Intranasal cocaine also produced prototypical stimulant-like subject-rated and physiological effects (e.g., increased ratings of Like Drug; elevated blood pressure). These data demonstrate that making alternative reinforcers easier to earn reduces cocaine self-administration, which has implications for treatment efforts.

Interaction Between Behavioral and Pharmacological Treatment Strategies to Decrease Cocaine Choice in Rhesus Monkeys

“…As expected, manipulations in the response requirement that increased the relative price of cocaine injections vs food pellets significantly decreased cocaine choice, whereas response requirement manipulations that decreased the relative price of cocaine injections vs food pellets significantly increased cocaine choice. These results are consistent with previous nonhuman primate (Czoty et al, 2005;Nader et al, 1992;Negus, 2003;Woolverton et al, 1997) and human laboratory (Greenwald and Hursh, 2006;Stoops et al, 2012) studies examining the behavioral determinants of drug choice. Moreover, our preclinical results may be analogous to epidemiological evidence for the price sensitivity of drug consumption, which provides a rationale for both governmental policies and more targeted contingency management strategies designed to reduce drug consumption by increasing drug price or facilitating access to nondrug alternatives (Dunlop et al, 2011;Grossman, 2005;Xu and Chaloupka, 2011).…”

“…Furthermore, both preclinical and human laboratory studies have demonstrated that cocaine choice is sensitive to manipulations in the response requirement associated with cocaine or the alternative reinforcer. For example, increases in the response requirement for cocaine or decreases in the response requirement for an alternative reinforcer can reduce cocaine choice and increase choice of the alternative (Hart et al, 2000;Nader and Woolverton, 1992;Negus, 2003;Stoops et al, 2012). Reciprocally, increases in the response requirement for the alternative reinforcer or decreases in the response requirement for cocaine can increase cocaine choice and reduce choices for the alternative (Hart et al, 2000;Nader et al, 1992;Negus, 2003).…”

Effects of Environmental Manipulations and Treatment with Bupropion and Risperidone on Choice between Methamphetamine and Food in Rhesus Monkeys

“…Previous human laboratory (Stoops et al, 2012) and preclinical studies (Nader and Woolverton, 1992;Negus, 2003) have demonstrated cocaine vs alternative reinforcer choice to be sensitive to response requirement manipulations. Recently, methamphetamine vs money choice in humans was also reported to be sensitive to response requirement manipulations such that a sixfold larger response requirement for money slightly, but not significantly, increased the number of methamphetamine capsules earned .…”

Effect of Delay on Self-Administration of Remifentanil under a Drug Versus Drug Choice Procedure in Rhesus Monkeys

“…Variables that impact choice can be examined experimentally in preclinical research using a variety of procedures (see reviews by Bergman and Paronis, 2006;Banks and Negus, 2012). For example, increasing the cost of drug or decreasing the cost of alternative nondrug reinforcers reduces drug taking in human (Stoops et al, 2012) and nonhuman primates (Nader and Woolverton, 1992;Negus, 2003). In addition to altering cost, changing other parameters of reinforcement can also significantly affect drug taking, such as increasing the time between a response and delivery of a reinforcer.…”