Contingency management interventions are quite successful at helping people change problematic behavior and in adopting behaviors related to the development of healthy lifestyles. One area in particular in which contingency management interventions have become a frontline treatment is for substance abuse. Contingency management interventions have been repeatedly demonstrated to be successful at initiating periods of abstinence from many different drugs of abuse in a variety of clinical samples. Typically, contingency management interventions for the treatment of drug abuse involve providing positive reinforcement for the provision of biological samples (e.g., urine or breath) that indicate recent abstinence. Generally these reinforcers are delivered each time a negative-sample is provided. However, basic science research into the delivery of reinforcement suggests that reinforcing behavior less frequently may, in fact, produce behavior that is more persistent once reinforcement has been discontinued. Similarly, basic research suggests that reducing the predictability of reinforcement promotes persistence of behavior change once reinforcement is withdrawn. These observations suggest a strategy for producing long-term behavior change. In substance abuse, this long-term behavior change could be reflected as long-term abstinence. The study outlined in this application is designed to examine whether less frequent and less predictable reinforcement of methamphetamine-negative urines leads to longer-term behavior change than more frequent and more predictable reinforcement. To accomplish this, we propose to compare 4 groups, all of which will receive a standardized psychosocial substance abuse treatment: (1) standard psychosocial treatment, (2) continuous contingency management: reinforcers available after each provision of a methamphetamine-negative urine test, (3) intermittent predictable contingency management: reinforcers available after the provision of every three consecutive methamphetamine-negative urine samples, and (4) intermittent unpredictable contingency management: reinforcers available on one day each week (randomly selected after the first week) for the provision of methamphetamine-negative urine samples provided all urine samples since delivery of the last reinforcer were also methamphetamine negative. Based on the widespread success of contingency management across many different applications, we believe that the results of the proposed study will have generality beyond the field of substance abuse treatment.
Contingency management refers to the systematic application of basic principles delineated by workers in the field of the Experimental Analysis of Behavior to treat the problem behavior of individuals. Primary emphasis is placed on the use of reinforcement and punishment to alter an individual’s day-to-day behavior. Contingency management has been used to promote a number of changes in behavior related to the development of healthy lifestyles (e.g., Giuffrida & Torgerson, 1997). Of particular importance to this application, a number of contingency management procedures have been refined for the treatment of a variety of substance use disorders and related problems (e.g., Higgins, Alessi & Dantona, 2002; Higgins & Silverman, 1999, Stitzer & Higgins, 1995). These procedures have been successful in reducing drug use (e.g., Higgins & Silverman, 1999; Petry, 2000). Recently, efforts have been undertaken to examine the different components involved in the delivery of contingency management interventions for the treatment of substance use disorders in order to understand what components of the interventions are needed to maximize treatment success and to attempt to make the interventions more suitable for use in community-based clinics. The study proposed in this application seeks to further our understanding of contingency management by investigating how different reinforcement procedures, used in combination with psychosocial drug abuse treatment, influence the long-term maintenance of abstinence among methamphetamine-dependent individuals.
There is a large body of basic-science research demonstrating that altering behavior via the intermittent delivery of reinforcement produces long-term behavior change relative to behavior that has been modified via continuous reinforcement (e.g., Robbins, 1971). This effect is further enhanced by introducing variability into the delivery of the intermittent reinforcement- that is, by making the delivery of the reinforcement less predictable (e.g., Rudy, 1971). We believe this effect can be exploited clinically to promote long-term behavior change.
It is appropriate to explore these issues in methamphetamine-dependent participants because we have evidence that methamphetamine use is amenable to treatment via contingency management (Roll, Huber, Shoptaw, Sodano & Chudzynski, submitted). While we are proposing to study the different reinforcement procedures in the context of the treatment of methamphetamine dependence, we expect the results to generalize to other behaviors that are commonly modified with contingency management interventions in the promotion of healthy life styles (e.g., medication compliance, adherence to exercise and diet regimens, obtaining prenatal care and childhood vaccinations, obtaining screenings for a variety of disorders and obtaining regular routine preventive medical care). The successful completion of the study outlined in this application will yield information on how the pattern of reinforcement delivery in a behavior change program can influence the likelihood of the behavior change persisting for a long period of time after the intervention has been discontinued.
To determine if different reinforcement procedures (i.e., schedules) produce different patterns of long-term abstinence from methamphetamine. Briefly the four study conditions are: (1) standard treatment which consists of 16 weeks of psychosocial treatment, (2) continuous contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are made available after each provision of a methamphetamine-negative urine test, (3) intermittent predictable contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are available after the provision of every three consecutive methamphetamine-negative urine samples, and (4) intermittent unpredictable contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are available on one day each week (randomly selected after the first week) for the provision of methamphetamine-negative urine samples provided all urine samples since delivery of the last reinforcer were also methamphetamine negative.
We anticipate that the three contingency management conditions will promote longer periods of abstinence in the year following treatment relative to the standard control group. Furthermore, we predict that the intermittent reinforcement procedures will produce longer periods of continued abstinence (i.e., long-term behavior change) in the year following treatment than the continuous reinforcement procedure. Finally, we predict that the intermittent unpredictable schedule will produce longer lasting behavior change than the intermittent predictable schedule. Methamphetamine use will be measured using urine toxicology and self-report of methamphetamine use.