Chapter 11 Contingency Management

Stephen T. Higgins, PhD

Vermont Center on Behavior and Health; Departments of Psychiatry and Psychological Science, University of Vermont

Allison N. Kurti, PhD

Vermont Center on Behavior and Health; Department of Psychiatry, University of Vermont

Diana R. Keith, PhD

Vermont Center on Behavior and Health; Department of Psychiatry, University of Vermont

Definitions and Background

Contingency management (CM) involves the systematic delivery of reinforcement contingent on achieving predetermined clinical targets or goals (e.g., abstinence from drug use) and withholding reinforcement or providing punitive consequences when those goals are unmet. This approach is based on the principles of operant conditioning, an area of psychology that focuses on the effects of environmental consequences on the probability of future behavior. Reinforcement refers to the behavioral process whereby an environmental consequence increases the future probability of a response, and punishment refers to the process whereby a consequence decreases the future probability of a response (see chapter 6). CM extends back to the 1960s and the advent of applied behavior analysis, behavior modification, and behavior therapy. More recently, the approach has come to be aligned with behavioral economics, although often under the heading of “financial incentives” rather than CM per se (S. T. Higgins, Silverman, Sigmon, & Naito, 2012). CM is typically used in combination with another psychosocial or pharmacological intervention rather than as a stand-alone intervention.

This research was supported by research grants R01HD075669 and R01HD078332 from the National Institute of Child Health and Human Development and award P20GM103644 of the National Institute of General Medical Sciences, Centers of Biomedical Research Excellence. Other than financial support, the funding sources had no other role in this project.

Beginning in the 1960s, case studies suggested that CM could be used as an applied intervention. Controlled studies in the areas of substance abuse (e.g., Stitzer, Bigelow, & Liebson, 1980), weight loss (Jeffery, Thompson, & Wing, 1978), and other applied areas soon provided proof-of-concept evidence that CM was a powerful therapeutic process. Nevertheless, CM garnered only relatively modest attention in the larger area of applied psychosocial approaches.

The growing use of cocaine fostered a striking rekindling of interest and research on CM (S. T. Higgins, Heil, & Lussier, 2004) for two major reasons. First, while virtually every other type of pharmacological and psychosocial intervention with cocaine-dependent outpatients was failing miserably, controlled clinical trials showed that CM reliably kept cocaine-dependent outpatients in treatment and substantially increased cocaine abstinence levels (S. T. Higgins et al., 1994). Second, researchers developed a monetary-based incentive program (i.e., vouchers exchangeable for retail items) to use with cocaine-dependent outpatients that was readily adaptable to a wide range of other clinical problems, unlike earlier programs that were often specific to a particular population (e.g., medication take-home privileges among methadone-maintained opioid-dependent outpatients).

A programmatic series of literature reviews on the use of vouchers and related financial incentives with substance-use disorders provides a continuous record of efficacy, from the seminal reports on treating cocaine dependence through the present (Lussier, Heil, Mongeon, Badger, & Higgins, 2006; S. T. Higgins, Sigmon, & Heil, 2011; Davis, Kurti, Redner, White, & Higgins, 2015). Between 1991 and 2015, 177 controlled studies reported in peer-reviewed journals examined the efficacy of systematically delivered financial incentives for reducing drug use (the vast majority of studies) or increasing adherence with other treatment regimens, such as clinic attendance or medication adherence. Eighty-eight percent (156/177) of those studies supported the efficacy of the CM intervention.

Researchers are now turning their attention in this area to reach into and dissemination in routine care; for example, studies are looking at interventions that integrate various technologies in order to increase their reach to populations living in remote areas, and interventions that integrate the treatment approach into routine care (Kurti et al., 2016). Two examples of the latter dissemination effort are CM becoming part of routine care in intensive substance-abuse treatment centers in the US Veterans Health Administration hospital system (Petry, DePhilippis, Rash, Drapkin, & McKay, 2014) and the use of CM to promote smoking cessation among pregnant women in economically disadvantaged communities in the United Kingdom (Ballard & Radley, 2009).

The use of CM has grown, reaching well beyond substance-use disorders to include exercise (e.g., Finkelstein, Brown, Brown, & Buchner, 2008), medication adherence (e.g., Henderson et al., 2015), and the use of shared physician and patient financial incentives to reduce biomarkers for cardiovascular disease (Asch et al., 2015). Because incentives are highly effective at promoting initial behavior change, researchers are now shifting attention to strategies to sustain treatment effects after the incentive programs have been discontinued (John, Loewenstein, & Volpp, 2012; Leahey et al., 2015).

The largest-scale interventions involving CM are in the area of global health (Ranganathan & Legarde, 2012). Conditional cash-transfer programs involve many millions of families throughout Latin America, Africa, and Asia. In Latin America impoverished mothers of young children can earn additional public assistance contingent on having their children immunized, participating in routine medical preventive care, and enrolling their children in school. In Africa, similar large-scale CM interventions have curtailed the AIDS epidemic by reducing sexually transmitted diseases, increasing rates of HIV testing, and promoting adult male circumcision, among other outcomes. These are complex efforts for which thorough and complete evaluations are not yet available, but reviews of this emerging literature offer many reasons for optimism regarding the effectiveness of large-scale incentive programs to promote health-related behavior change (Ranganathan & Legarde, 2012).

The institutional and cultural support for CM appears to be increasing. In the United States, financial incentives were thoroughly integrated into the landmark 2009 Patient Protection and Affordable Care Act (ACA). The ACA established the groundwork for US employers to use incentives as part of employee wellness programs, and the majority of major US employers are now doing so (Mattke et al., 2013). The ACA also requires the US Center for Medicare and Medicaid Services to allocate funds (roughly $85 million annually) to examine the use of financial incentives to promote health-related behavior change in such areas as smoking cessation, weight loss, medication adherence, and the like to prevent chronic disease among economically disadvantaged individuals (Centers for Medicare and Medicaid Services, 2017).

Basic Components

Simply offering financial incentives for behavior change does not qualify as CM. CM is dependent on basic design features that have been developed from CM research, and the principle of reinforcement, which is the core process of this treatment approach (S. T. Higgins, Silverman, & Washio, 2011). Below we outline ten features of CM interventions that are important to their efficacy:

Explain the details of the intervention carefully prior to treatment and provide a written description when possible.
Define objectively the response (e.g., drug-negative urine toxicology results) being targeted by the CM intervention (e.g., drug abstinence).
Identify in advance the methods to be used for verifying that the target response has occurred (e.g., urine toxicology testing).
Outline clearly the schedule for monitoring progress.
Monitor progress frequently to provide opportunities for patients to experience the programmed consequences.
Stipulate clearly in advance the duration of the intervention.
Pinpoint a single rather than multiple behavioral targets when possible.
Make clear the consequences of success and failure in meeting targeted goals.
Keep delays as short as practical when delivering earned incentives since treatment effect size varies inversely with delay.
Be mindful that treatment effect size varies inversely with the monetary value of the incentive provided.

Case Study

To outline the CM treatment approach in greater detail, we will use an example of smoking cessation among pregnant women. Cigarette smoking during pregnancy continues to represent a serious public health problem that increases risk for catastrophic pregnancy complications, adverse effects on fetal development, and disease throughout the life span. While the prevalence of smoking during pregnancy has decreased over time, economically disadvantaged pregnant women continue to smoke at much higher rates than more-affluent women. Meta-analyses of more than seventy-seven controlled trials and twenty-nine thousand women show that CM produces the largest effect sizes by several orders of magnitude as compared with pharmacological or other psychosocial interventions (Lumley et al., 2009; Chamberlain et al., 2013). Across eight controlled trials of CM (see figure 1), the odds of late-pregnancy abstinence were 3.79 (95% confidence intervals, or CIs: 2.74–5.25) times greater than with control interventions (Cahill, Hartmann-Boyce, & Perera, 2015).

University of Vermont model. The CM model developed at the University of Vermont is the most thoroughly researched for this population (S. T. Higgins, Washio et al., 2012). In this body of work, women who enter prenatal care and report that they continue to smoke are recruited from community ob-gyn providers. After entering the study, they are encouraged to begin their cessation effort on either of the following two Mondays. For the initial five consecutive days (Monday through Friday) of the quit attempt, they report to the clinic daily to have their smoking status monitored. During those initial visits, “abstinence” is defined as having a breath carbon monoxide (CO) level of less than or equal to six parts per million. Because of the relatively long half-life of cotinine (the principal metabolite of nicotine), it cannot be used to verify abstinence in the initial days of the quit attempt. Starting on Monday of the second week of the quit attempt, biochemical verification transitions from breath CO to urine cotinine testing (≤ 80 ng/ml). At that point, the frequency of clinic contact to monitor smoking status decreases to twice weekly, where it remains for the next seven weeks, at which point it decreases to once weekly for four weeks, and then to every other week until delivery. During the postpartum period, abstinence monitoring increases again to once weekly for four weeks, and then decreases to every other week through twelve weeks postpartum. Follow-up assessments are conducted at twenty-four weeks and, more recently, fifty weeks postpartum.

The voucher-based incentive program is in place from the start of the quit attempt through twelve weeks postpartum. Voucher value begins at $6.25 and escalates by $1.25 for each consecutive negative specimen, reaching a maximum of $45.00, where it remains through the remainder of the intervention. However, a positive test result, failure to provide a scheduled specimen, or a missed visit resets the value of vouchers back to their initial low value, and two consecutive negative tests restore voucher value to the pre-reset level. A woman who is continuously abstinent throughout the duration of treatment typically can earn around $1,180, depending on how many weeks pregnant she is when she starts treatment. In a clinical trial to improve treatment response that is currently under way, women who smoke ten or more cigarettes per day at study intake are eligible to receive vouchers according to the same schedule described above, but at double the incentive value.

Figure 2 compares the combined results from the initial three trials conducted with the intervention using the $1,180 maximal-earnings model to a control condition wherein vouchers of the same values were delivered independent of smoking status. Late-pregnancy abstinence levels were almost fivefold greater among women treated with abstinence-contingent versus noncontingent vouchers (34% versus 7%). Abstinence rates in both treatment conditions decreased during the postpartum period, but abstinence-contingent incentives continued to show an advantage even twelve weeks after the discontinuation of the incentives.

Table 1 shows birth outcomes among women from those trials. Mean birth weight was significantly greater, and the percentage of infants born with especially low birth weight (< 2,500 g) was significantly lower, among infants born to mothers treated with abstinence-contingent vouchers compared to noncontingent vouchers.

Figure 2. Assessments of seven-day point-prevalence abstinence at the end of pregnancy and at twelve and twenty-four weeks postpartum in contingent (n = 85) and noncontingent (n = 81) voucher-treatment conditions. The asterisk (*) indicates a significant difference between conditions (p ≤.003 across the three assessments).

Contingent

Noncontingent

Table 1. Infant outcomes at delivery

Measure	Contingent (n = 85)	Noncontingent (n = 81)	p values
Birth weight (grams)	3,295.6 ± 63.8	3,093.6 ± 67.0	.03
% Low birth weight	5.9	18.5	.02
Gestational age (weeks)	39.1 ± 0.2	38.5 ± 0.3	.06
% Preterm births	5.9	13.6	.09
% NICU admissions	4.7	13.8	.06
Values represent mean ± standard error, unless specified otherwire. NICU: neonatal intensive care unit.

Although the incentives of these programs may sound expensive, a recent formal analysis of the largest trial yet reported of this treatment approach for pregnant smokers (Tappin et al., 2015) demonstrates that it is highly cost-effective (Boyd, Briggs, Bauld, Sinclair, & Tappin, 2016). Furthermore, research shows that CM can be moved into a community setting without losing efficacy. A recent study implemented CM using regular obstetrical staff and community smoking-cessation personnel in a large urban hospital (Ierfino et al., 2015) and found that 20 percent of women achieved abstinence as compared with 0 percent among historical controls.

To convey a sense of the use of this incentives intervention at the level of an individual participant, we share the experience of Jamie, an unemployed twenty-one-year-old who was living in low-income housing when she learned that she was pregnant with her second child. She had smoked throughout her first pregnancy, and although her daughter from that pregnancy had been born within the normal range of birth weight, Jamie did not want to risk smoking through a second pregnancy.

Age when initiating smoking and the number of prior quit attempts are important predictors of success, and both indicated that quitting was going to be difficult for Jamie: she had started smoking at age fourteen and had made only two quit attempts in the preceding seven years, with her longest attempt lasting a mere two days. Even after learning of her second pregnancy, when entering prenatal care Jamie was still smoking ten cigarettes per day, and she smoked her first cigarette of the day within thirty minutes of waking (an empirically based indicator of nicotine dependence). Ten cigarettes per day is considered relatively heavy smoking in the pregnant population, as most women reduce the daily number of cigarettes they smoke by approximately half before entering prenatal care (Heil et al., 2014). Despite having numerous characteristics associated with a poor prognosis for successful cessation, Jamie expressed strong determination to quit.

Jamie was enrolled in the CM intervention when she was approximately seven weeks pregnant. Her cotinine level on the day of enrollment was 729 ng/ml, quite a bit higher than the 80 ng/ml cut point needed to earn vouchers during the intervention. However, in her eagerness to quit, Jamie selected the earliest possible Monday as her quit date—a mere six days away.

Other than the two puffs that Jamie took on her first day of treatment, she reported abstaining from smoking entirely during her first week, earning a total $87.50, which she opted to redeem in the form of a gift card to the nearest grocery store. After a successful first week, Jamie recognized the importance of remaining abstinent over the weekend. The following Monday was her “transition day,” when urine cotinine replaced breath CO levels for bioverification of abstinence. Breath CO has a much shorter half-life than cotinine and thus is less sensitive to low-level or intermittent smoking (S. T. Higgins et al., 2006). Even one puff could have shown up in her urine cotinine test, thereby resetting her voucher earnings to the initial value of $12.50.

Despite living with a smoker and having a substantial number of friends who smoked, Jamie managed to avoid smoking over the weekend, and her urine cotinine levels were well below the cut point for abstinence. This transition day is a robust predictor of late-pregnancy abstinence (S. T. Higgins et al., 2007), and consistent with this pattern Jamie remained abstinent throughout the remainder of her pregnancy and through 1 year postpartum—9 months after the discontinuation of the incentive program. Jamie used her voucher earnings to pay for practical economic demands (e.g., groceries, gas, phone bills) and items for her soon-to-arrive second daughter.

Importantly, Jamie gave birth to a healthy baby girl and had a normal vaginal delivery without complications. Emily was born at a gestational age of 39.1 weeks and a birth weight of 3,221 grams. These outcomes align well with those achieved by women who received this intervention in our prior trials, in which mean gestational age was 39.1 weeks and birth weight was 3,295 grams (see table 1; also see S. T. Higgins et al., 2010). Mean gestational age and birth weight among women in the control conditions in those prior trials were 38.5 weeks and 3,093 grams, respectively. Moreover, had Jamie not been successful in quitting smoking, her baby may have been among the 14 percent of infants of the control condition who were born preterm (< 37 weeks), or the 18.5 percent who met the medical cut point for low birth weight (< 2,500 g), or the 14 percent who were admitted to the NICU. Instead, Emily was admitted to the newborn nursery on December 23 and discharged the following day. Jamie’s abstinence through the postpartum period leading to the one-year follow-up was a strong indication that Jamie was well on her way to life as a nonsmoker. It also suggested that Emily will be protected from the serious adverse health effects of secondhand smoke exposure from Mom’s smoking. Jamie breast-fed exclusively for approximately one month and then breast-fed and formula-fed for 10.75 months, which far exceeds the pattern of early weaning typical of maternal smokers. This pattern is associated with important short- and longer-term maternal and child health benefits (T. M. Higgins et al., 2010).

Future Directions

Although practitioners are using CM treatments to treat substance abuse and other problem areas, CM is potentially relevant to a much wider range of clinical problems. As just one example, cardiac rehabilitation is an efficacious and cost-effective program for improving the health outcomes and reducing the rehospitalization rates of individuals with cardiovascular disease. Unfortunately, economically disadvantaged patients use this service far less frequently than more affluent patients, despite their medical insurance covering the costs and, on average, having greater medical need for the care (Ades & Gaalema, 2012). Initial research is showing that CM is effective at increasing participation in cardiac rehabilitation and improving health outcomes among economically disadvantaged patients (Gaalema et al., 2016).

CM interventions do not represent a silver bullet. For example, even in studies in which CM is efficacious, half or more of the treated individuals fail to benefit. Nonresponders typically are individuals who have more severe problems and may need a more intensive intervention. Significantly increasing incentives has been shown to reach many nonresponders (Silverman, Chutuape, Bigelow, & Stitzer, 1999), and other treatment combinations may be possible. For example, at least one study has associated CM nonresponse among cocaine users with avoidance and behavioral inflexibility in the presence of cocaine-related thoughts (Stotts et al., 2015). Perhaps combining CM with treatments that have efficacy in that domain, or emotion regulation skills more generally, could be helpful (Bickel, Moody, & Higgins, 2016; Hayes, Luoma, Bond, Masuda, & Lillis, 2006).

It is also important for CM developers to attend to how behavior change can be sustained once incentives are discontinued. For example, developers could pay more attention to how more-natural incentives already available in the physical and electronic community could be leveraged to support treatment gains once formal treatment is discontinued (people treated with incentives to increase physical activity or weight loss could join community walking or running groups following treatment, or CM could be integrated with online support groups that continue beyond the incentive period).

It’s also going to be important to examine the cost-effectiveness of long-term CM interventions. CM is being used to assist in the management of chronic conditions. Just as chronic medications are often necessary to effectively manage these chronic conditions, chronic behavior-change interventions may be necessary as well. It is relatively easy to think through the logistics of providing long-term incentives for healthy behavior change with employee wellness programs. While the logistics may be less straightforward in the public sector, the efficacy and cost-effectiveness of longer-term CM interventions should be carefully examined. Cost-effectiveness will be an important guidepost in all such efforts.

We used the long-standing problem of smoking cessation among pregnant women to illustrate the potential power of this treatment approach. The growing body of evidence on the efficacy of CM, and its close alignment to fundamental principles of behavioral science, should give psychology and psychotherapy practitioners confidence that this approach has the potential to substantially help reduce the adverse individual and societal impacts of behavior and health problems. The tremendous growth in the use of CM in the public and private sectors in the past two decades suggests that CM has a home in mental and behavioral health care across the board.

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