Association for Behavior Analysis International

The talks presented in this symposium will celebrate the contributions of Charles R Schuster, known by everyone as Bob, to behavioral pharmacology by colleagues who directly trained with him. One of Bob's major contributions was the development of the drug self-administration paradigm demonstrating that drugs abused by humans could serve as positive reinforcers in non-human primates. Later, he extended this model of drug-taking behavior to humans. The findings that drugs were similar to other reinforcers in their ability to control behavior completely changed the conceptualization of drug abuse and the paradigm became a major component of the field of behavioral pharmacology. It also allowed the application of the tools and findings of behavioral analysis to further the understanding of the determinants of drug-taking behavior. A major variable controlling self-administration was the availability and nature of alternative reinforcers. In this symposium, each of the four talks will focus on the impact of alternative reinforcers on self-administration behavior. The final talk will demonstrate how the experimental findings in both in non-humans and humans have stimulated the development of innovative behavioral treatments for drug abuse

Those interested in behavioral pharamcology, in methods of the experimental analysis of behavior, and in the history of behavior analysis.

• Idenitfy Charles R. Schuster's immense contributions to behavior analysis, behavioral pharmacology, and science in general.
• Articulate his contributions to the study of drug abuse and to the development of methods to treat drug abuse.

Much of behavior, including self-administration of abused drugs, may be conceptualized as involving a choice among available alternatives. Laboratory research involving non-humans has substantially contributed to our understanding of the behavioral determinants of drug choice. It has been demonstrated that the relative magnitude drug and non-drug alternatives, as well relative cost, frequency and probability of reinforcement can all influence the choice to take a drug. In recent experiments, we have found that introducing a delay between the self-administration response and drug delivery can diminish the effectiveness of a drug as a reinforcer. Similarly, delaying the delivery of punisher can decrease the effectiveness of punishment of drug self-administration. For both reinforcement and punishment, the relationship between delay and effectiveness was well predicted by a hyperbolic discounting function. Thus, research with non-humans has much to contribute to our understanding of behavioral factors that can influence drug self-administration. By extension, basic research with non-humans can help suggest behavioral treatment strategies that may be useful alone or in conjunction with pharmacological treatment.

Schedule-induced polydipsia (SIP) is a form of adjunctive behavior that is generated when small proportions of food are delivered under intermittent schedules of reinforcement. The term was coined by John Falk and emphasizes both excessiveness (polydipsia) and the adjunctive relationship to the generating schedule (induced). Although most adjunctive behaviors rapidly dissipate when the induction schedule is terminated, SIP using an alcohol solution may establish a lifetime of robust, heavy alcohol self-administration. In other words, SIP can be used to establish alcohol intoxication (indicated by a blood ethanol concentration of >80 mg/dl) as a primary reinforcer. In monkeys subjected to SIP as an initial introduction to ethanol self-intoxication there are individual differences in the probability of future heavy drinking. Using a principal component analysis, the most robust predictor of future heavy drinking is the emergence of rapidly drinking (gulping) a six-drink equivalent (1.5 g/kg) under the SIP conditions. The monkeys that gulp alcohol during SIP subsequently self-administer enough alcohol to produce physical dependence. In contrast, monkey that sip their six-drink equivalent rarely drink an intoxicating dose. It is proposed that the gulping phenotype reflects the reinforcing efficacy of alcohol intoxication and probability of lifetime dependence upon alcohol.

Opportunity cost (OC) is a key concept in behavioral economics. OC refers to the total value (including explicit and implicit time and money) of alternative options that are foregone (not chosen). The study of OC involves understanding relations between choice and scarcity of options available to the individual. This is central to addictive behavior because substance abusers (particularly those who are physically dependent) habitually make choices that sacrifice access to non-drug alternatives. This talk will discuss (1) experimental data with heroin and cocaine abusers that illustrate this concept; and (2) implications for therapeutic approaches to schedule alternatives that may increase the probability of addictive behavior change.

This presentation will describe a program of research to develop an operant treatment for drug addiction that was heavily influenced by Charles R. Schuster (Bob). Bob, Kenzie Preston, and I began this research at NIDA's Addiction Research Center in Baltimore in the early 1990s. Our studies showed that voucher reinforcement in which patients received monetary vouchers contingent on providing drug-free urine samples could promote cocaine and heroin abstinence in low-income, injection drug users in methadone treatment. Although promising, half of the patients did not respond and many who did relapsed when the voucher intervention was discontinued. Influenced and encouraged by early discussions with Bob, my colleagues and I have been developing an intervention designed to promote abstinence in a large proportion of patients and maintain that abstinence over extended periods of time. The intervention harnesses the reinforcing value of paid employment to finance and maintain abstinence reinforcement. Under this intervention, individuals are hired and paid to work. To reinforce abstinence, participants are required to provide objective evidence of drug abstinence to maintain access to the workplace and maintain maximum pay. This presentation will describe this research program and discuss Bobs invaluable role in the development and future of this intervention.