Shaping cocaine abstinence by successive approximation

The reflections of health service providers on implementing contingency management for methamphetamine use disorder in Australia

INTRODUCTION

Contingency management (CM) is the most effective treatment for reducing methamphetamine use. We sought to understand why CM has not been taken up to manage methamphetamine use disorder in Australia.

METHODS

Six focus groups (4-8 participants per group) were conducted with health workers from agencies in Australia that provided drug-related health care to people who use methamphetamine. These agencies had no previous experience delivering CM for substance use. The potential acceptability and feasibility of implementing CM in their services were discussed.

RESULTS

Participants felt that it would be beneficial to have an evidence-based treatment for methamphetamine use disorder. This sentiment was offset by concerns that CM conflicted with a client-centred harm-reduction approach and that it dictated the goal of treatment as abstinence. It was also perceived as potentially coercive and seen to reify the power imbalance in the therapeutic relationship and therefore potentially reinforce stigma. There was also concern about the public's perception and the political acceptability of CM, who would fund CM, and the inequity of providing incentives only to clients with a methamphetamine use disorder. Some concerns could be ameliorated if the goals and structure of CM could be tailored to a client's needs.

DISCUSSION AND CONCLUSIONS

Many healthcare workers were keen to offer CM as an effective treatment option for people with methamphetamine use disorder, but CM would need to be sufficiently flexible to allow it to be tailored to client needs and implemented in a way that did not adversely impact the therapeutic relationship.

Contingency Management for Patients Receiving Medication for Opioid Use Disorder: A Systematic Review and Meta-analysis

Importance

Medication treatment for opioid use disorder (MOUD) is efficacious, but comorbid stimulant use and other behavioral health problems often undermine efficacy.

Objective

To examine the association of contingency management, a behavioral intervention wherein patients receive material incentives contingent on objectively verified behavior change, with end-of-treatment outcomes for these comorbid behavioral problems.

Data Sources

A systematic search of PubMed, Cochrane CENTRAL, Web of Science, and reference sections of articles from inception through May 5, 2020. The following search terms were used: vouchers OR contingency management OR financial incentives.

Study Selection

Prospective experimental studies of monetary-based contingency management among participants receiving MOUD.

Data Extraction and Synthesis

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, 3 independent investigators extracted data from included studies for a random-effects meta-analysis.

Main Outcomes and Measures

Primary outcome was the association of contingency management at end-of-treatment assessments with 6 clinical problems: stimulant use, polysubstance use, illicit opioid use, cigarette smoking, therapy attendance, and medication adherence. Random-effects meta-analysis models were used to compute weighted mean effect size estimates (Cohen d) and corresponding 95% CIs separately for each clinical problem and collapsing across the 3 categories assessing abstinence and the 2 assessing treatment adherence outcomes.

Results

The search identified 1443 reports of which 74 reports involving 10 444 unique adult participants met inclusion criteria for narrative review and 60 for inclusion in meta-analyses. Contingency management was associated with end-of-treatment outcomes for all 6 problems examined separately, with mean effect sizes for 4 of 6 in the medium-large range (stimulants, Cohen d = 0.70 [95% CI, 0.49-0.92]; cigarette use, Cohen d = 0.78 [95% CI, 0.43-1.14]; illicit opioid use, Cohen d = 0.58 [95% CI, 0.30-0.86]; medication adherence, Cohen d = 0.75 [95% CI, 0.30-1.21]), and 2 in the small-medium range (polysubstance use, Cohen d = 0.46 [95% CI, 0.30-0.62]; therapy attendance, d = 0.43 [95% CI, 0.22-0.65]). Collapsing across abstinence and adherence categories, contingency management was associated with medium effect sizes for abstinence (Cohen d = 0.58; 95% CI, 0.47-0.69) and treatment adherence (Cohen d = 0.62; 95% CI, 0.40-0.84) compared with controls.

Conclusions and Relevance

These results provide evidence supporting the use of contingency management in addressing key clinical problems among patients receiving MOUD, including the ongoing epidemic of comorbid psychomotor stimulant misuse. Policies facilitating integration of contingency management into community MOUD services are sorely needed.

Toward an experimental analysis of verbal shaping in psychotherapy

AbstractObjective. Some authors have suggested that verbal shaping is an active component in cognitive restructuring. The goal of the current study was to provide experimental evidence in support of the shaping hypothesis.

METHOD

Three consecutively admitted adults with symptoms of anxiety and depression participated in the study. Participants underwent baseline, treatment comparison, crossover, and follow-up phases as part of an experimental single-case study. We selected two target irrational beliefs and praised either the client's approximations to a terminal (more adaptive) class of verbalizations (differential reinforcement of approximations) or just the terminal class of verbalizations (terminal reinforcement).

RESULTS

Irrational beliefs exposed to differential reinforcement of approximations was a more effective approach to reducing irrational beliefs.

CONCLUSION

The study provides experimental evidence in support of the verbal shaping hypothesis. Our findings suggest that it may be possible to enhance clinical outcomes by actively engaging in verbal shaping during client-therapist verbal interaction.

Comparison of Treatments for Cocaine Use Disorder Among Adults: A Systematic Review and Meta-analysis

IMPORTANCE

In the US and the United Kingdom, cocaine use is the second leading cause of illicit drug overdose death. Psychosocial treatments for cocaine use disorder are limited, and no pharmacotherapy is approved for use in the US or Europe.

OBJECTIVE

To compare treatments for active cocaine use among adults.

DATA SOURCES

PubMed and the Cochrane Database of Systematic Reviews were searched for clinical trials published between December 31, 1995, and December 31, 2017.

STUDY SELECTION

This meta-analysis was registered on Covidence.org (study 8731) on December 31, 2015. Clinical trials were included if they (1) had the term cocaine in the article title; (2) were published between December 31, 1995, and December 31, 2017; (3) were written in English; (4) enrolled outpatients 18 years or older with active cocaine use at baseline; and (5) reported treatment group size, treatment duration, retention rates, and urinalysis results for the presence of cocaine metabolites. A study was excluded if (1) more than 25% of participants were not active cocaine users or more than 80% of participants had negative test results for the presence of cocaine metabolites at baseline and (2) it reported only pooled urinalysis results indicating the presence of multiple substances and did not report the specific proportion of positive test results for cocaine metabolites. Multiple reviewers reached criteria consensus. Of 831 records screened, 157 studies (18.9%) met selection criteria and were included in the analysis.

DATA EXTRACTION AND SYNTHESIS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. Search results were imported from PubMed XML into Covidence.org then Microsoft Excel. Data extraction was completed in 2 iterations to ensure fidelity. Analyses included a multilevel random-effects model, a multilevel mixed-effects meta-regression model, and sensitivity analyses. Treatments were clustered into 11 categories (psychotherapy, contingency management programs, placebo, opioids, psychostimulants, anticonvulsants, dopamine agonists, antidepressants, antipsychotics, miscellaneous medications, and other therapies). Missing data were imputed using multiple imputation by chained equations. The significance threshold for all analyses was P = .05. Data were analyzed using the metafor and mice packages in R software, version 3.3.2 (R Foundation for Statistical Computing). Data were analyzed from January 1, 2018, to February 28, 2021.

MAIN OUTCOMES AND MEASURES

The primary outcome was the intention-to-treat logarithm of the odds ratio (OR) of having a negative urinalysis result for the presence of cocaine metabolites at the end of each treatment period compared with baseline. The hypothesis, which was formulated after data collection, was that no treatment category would have a significant association with objective reductions in cocaine use.

RESULTS

A total of 157 studies comprising 402 treatment groups and 15 842 participants were included. Excluding other therapies, the largest treatment groups across all studies were psychotherapy (mean [SD] number of participants, 40.04 [36.88]) and contingency management programs (mean [SD] number of participants, 37.51 [25.51]). Only contingency management programs were significantly associated with an increased likelihood of having a negative test result for the presence of cocaine (OR, 2.13; 95% CI, 1.62-2.80), and this association remained significant in all sensitivity analyses.

CONCLUSIONS AND RELEVANCE

In this meta-analysis, contingency management programs were associated with reductions in cocaine use among adults. Research efforts and policies that align with this treatment modality may benefit those who actively use cocaine and attenuate societal burdens.

Using a randomized controlled trial to test whether modifications to contingency management improve outcomes for heavy drinkers with serious mental illness

BACKGROUND

In contingency management (CM), individuals receive rewards for alcohol abstinence. CM is associated with reduced alcohol use in adults with co-occurring serious mental illnesses (SMI). Pre-treatment urine ethyl glucuronide (uEtG) levels equivalent to daily heavy drinking (uEtG >349ng/mL) are associated with poor response to CM. Modifications to CM are needed to improve outcomes for non-responders.

AIMS

To determine if pre-treatment heavy drinkers, defined by uEtG, with SMI achieve higher levels of alcohol abstinence when they receive an increased magnitude of reinforcement for abstinence (High-Magnitude CM) or reinforcers for reduced drinking, prior to receiving reinforcers for abstinence (Shaping CM), relative to those who receive typical low-magnitude abstinence based CM (Usual CM). Additionally, variables in the Addictions Neuroclinical Assessment model will be examined as treatment response moderators.

METHODS

Participants (N=400) will be recruited from two urban mental health organizations and complete a 4-week induction period where they will be reinforced for submitting samples for uEtG testing. Participants who attain a mean uEtG >349mg/mL will be randomized to receive either Usual CM, High-Magnitude CM, or Shaping CM for 16weeks. Differences in abstinence, assessed by uEtG, will be examined during treatment and during a 12-month follow-up. Measures of negative emotionality, alcohol reinforcer salience, and executive functioning will be gathered at study intake and used to predict treatment outcomes.

DISCUSSION

This novel approach to CM will use an alcohol biomarker to identify those at risk for treatment non-response and determine if adaptations to CM might improve outcomes for this group.

Cocaine choice procedures in animals, humans, and treatment-seekers: Can we bridge the divide?

Individuals with cocaine use disorder chronically self-administer cocaine to the detriment of other rewarding activities, a phenomenon best modeled in laboratory drug-choice procedures. These procedures can evaluate the reinforcing effects of drugs versus comparably valuable alternatives under multiple behavioral arrangements and schedules of reinforcement. However, assessing drug-choice in treatment-seeking or abstaining humans poses unique challenges: for ethical reasons, these populations typically cannot receive active drugs during research studies. Researchers have thus needed to rely on alternative approaches that approximate drug-choice behavior or assess more general forms of decision-making, but whether these alternatives have relevance to real-world drug-taking that can inform clinical trials is not well-understood. In this mini-review, we (A) summarize several important modulatory variables that influence cocaine choice in nonhuman animals and non-treatment seeking humans; (B) discuss some of the ethical considerations that could arise if treatment-seekers are enrolled in drug-choice studies; (C) consider the efficacy of alternative procedures, including non-drug-related decision-making and 'simulated' drug-choice (a choice is made, but no drug is administered) to approximate drug choice; and (D) suggest opportunities for new translational work to bridge the current divide between preclinical and clinical research.

Sex effects in cocaine-using methadone patients randomized to contingency management interventions

Contingency management (CM) is an effective treatment for promoting cocaine abstinence in patients receiving methadone maintenance. However, few studies have examined the effect of sex on treatment outcomes in this population. This study evaluated the impact of sex on longest duration of abstinence (LDA) and percent negative urine samples in 323 cocaine-using methadone patients from 4 randomized clinical trials comparing CM to standard methadone care. Overall, women had better treatment outcomes compared with men, demonstrated by an increase in both LDA and percentages of negative samples. Patients receiving CM also had significantly higher LDA and percentages of negative samples compared to patients receiving standard care, but sex by treatment condition effects were not significant. These data suggest that cocaine-using methadone patients who are women have better substance use outcomes than men in interventions that regularly monitor cocaine use, and CM is equally efficacious regardless of sex.

The effects of percentile versus fixed criterion schedules on smoking with equal incentive magnitude for initial abstinence

Incentives have been successfully used to reduce smoking in hard-to-treat (HTT) smokers by progressively reinforcing lower levels of breath carbon monoxide (CO). When compared with schedules only providing incentives for smoking abstinence, using a progressive (percentile) criterion facilitates longer periods of smoking abstinence. However, participants receiving incentives for lower breath CO levels on percentile schedules typically earn more for their first abstinent breath CO sample relative to participants receiving incentives only for smoking abstinence. Many studies show that larger incentive magnitude increases abstinence rates. The present study tested the effects of different incentive schedules on rates of abstinence maintenance while holding the initial incentive magnitude constant for 93 HTT smokers to eliminate initial abstinence incentive magnitude as a potential confound. Smokers were randomized to percentile, fixed criterion, or random incentive schedules. The incentive magnitude for the first abstinent breath CO sample (<3 ppm) was $5 for percentile and fixed criterion incentive participants, and then increased by $0.50 for each consecutive abstinent breath CO sample. All groups had similar patterns of meeting the abstinence criterion for at least 1 visit. However, once this abstinence criterion was met, abstinence was more likely to be maintained by fixed criterion incentive participants. Unlike previous studies comparing percentile and fixed criterion schedules, percentile incentive schedules were not associated with longer periods of abstinence relative to fixed criterion incentive schedules. Further studies that manipulate initial incentive magnitude are needed to test whether the difference between the current and previous studies was due to initial incentive magnitude.

Randomized clinical trial examining duration of voucher-based reinforcement therapy for cocaine abstinence

BACKGROUND

This is the first study to systematically manipulate duration of voucher-based reinforcement therapy (VBRT) to see if extending the duration increases abstinence during and following VBRT.

METHODS

We randomized cocaine-dependent methadone-maintained adults to Standard (12 weeks; n=62) or Extended (36 weeks; n=68) VBRT and provided escalating voucher amounts contingent upon urinalysis verification of cocaine abstinence. Urinalysis was scheduled at least every 2 weeks during the 48-week study and more frequently during VBRT (3/week) and 12 weeks of Aftercare (2/week).

RESULTS

Extended VBRT produced longer durations of continuous cocaine abstinence during weeks 1-24 (5.7 vs 2.7 weeks; p=0.003) and proportionally more abstinence during weeks 24-36 (X(2)=4.57, p=.03, OR=2.18) compared to Standard VBRT. Duration of VBRT did not directly predict after-VBRT abstinence; but longer continuous abstinence during VBRT predicted abstinence during Aftercare (p=0.001) and during the last 12 weeks of the study (p<0.001). Extended VBRT averaged higher monthly voucher costs compared to Standard VBRT ($96 vs $43, p<.001); however, the average cost per week of abstinence attained was higher in the Standard group ($8.06 vs $5.88, p<.001). Participants in the Extended group with voucher costs exceeding $25 monthly averaged 20 weeks of continuous abstinence.

CONCLUSIONS

Greater abstinence occurred during Extended VBRT, but providing a longer duration was not by itself sufficient to maintain abstinence after VBRT. However, if abstinence can be captured and sustained during VBRT, then providing longer durations may help increase the continuous abstinence that predicts better long-term outcomes.

Duration effects in contingency management treatment of methamphetamine disorders

The primary aim of this study was to determine whether different durations of contingency management (CM) in conjunction with psychosocial treatment produced different rates of abstinence among methamphetamine dependent individuals. Participants were randomized to one of the four 16-week treatment conditions: standard psychosocial treatment or psychosocial treatment plus one of the three durations of CM (one-month, two-month, or four-month). A total of 118 participants were randomized to the four treatment conditions. There were significant differences across treatment conditions for number of consecutive days of methamphetamine abstinence (p<0.05). These differences were in the hypothesized direction, as participants were more likely to remain abstinent through the 16-week trial as CM duration increased. A significant effect of treatment condition (p<0.05) and time (p<0.05) on abstinence over time was also found. Longer durations of CM were more effective for maintaining methamphetamine abstinence.

Dysregulation of diurnal cortisol secretion affects abstinence induction during a lead-in period of a clinical trial for depressed cocaine-dependent patients

BACKGROUND AND OBJECTIVE

Hypothesizing that stress dysregulation may worsen cocaine dependence, we investigated the effect of diurnal cortisol secretion profile, suppression of cortisol secretion, and total cortisol secretion on retention, abstinence-based voucher earnings, days of cravings, and mood status of participants at the end of a 2-week medication-free lead-in prior to randomization in a clinical trial of mirtazapine (60 mg vs. placebo) for depressed cocaine-dependent patients.

METHODS

We measured saliva cortisol levels at 9 AM, 2 PM, and 5 PM on the first two consecutive days of a 2-week medication-free lead-in period. Results from saliva samples were used to estimate the total daily level of cortisol, the diurnal profile of secretion (typical vs. atypical), and response to dexamethasone suppression (.1 mg). Seventy-seven patients collected saliva samples at baseline, and 65 (85%) were suitable for profile analysis.

RESULTS

Patients with typical profiles (52%) collected significantly more abstinence-based voucher earnings during the lead-in (U = 299.50, p = .025). Diurnal secretion profile did not significantly affect mood status, days of craving, or retention. There were no significant effects of suppression of cortisol secretion or of total cortisol levels on any outcome measures.

CONCLUSION

In a subgroup of cocaine-dependent patients, deviation of cortisol secretion away from the homeostatic diurnal pattern was associated with reduced success at achieving early abstinence, an important determinant of treatment success.

Contingent incentives reduce cigarette smoking among pregnant, methadone-maintained women: results of an initial feasibility and efficacy randomized clinical trial

AIMS

This study examined the feasibility and efficacy of behavioral incentives for reducing cigarette smoking among pregnant methadone-maintained patients.

DESIGN

Participants (n = 102) were assigned randomly to: (i) contingent behavioral incentives (CBI: n = 42); (ii) non-contingent behavioral incentives (NCBI: n = 28); or (iii) treatment as usual (TAU: n = 32).

SETTING

Study procedures were implemented at the Center for Addiction and Pregnancy in Baltimore, MD.

PARTICIPANTS

Study participants were pregnant, methadone-maintained women enrolled in substance use disorder treatment.

MEASUREMENTS

Baseline carbon monoxide (CO) levels were calculated for each participant. Subsequently, breath samples were tested three times weekly to measure changes in smoking behavior. CBI participants received incentives for target reductions from baseline: any reduction (week 1); 10% reduction (weeks 2-4), 25% reduction (weeks 5-7), 50% reduction (weeks 8-9), 75% reduction (week 10-11); and abstinence [CO < 4 parts per million (p.p.m.)] (week 12 until delivery). NCBI participants received incentives independent of smoking CO measurement results. TAU participants received no incentives, the standard treatment at the program.

FINDINGS

CBI condition participants submitted significantly lower mean CO values than the NCBI and TAU conditions over the course of the intervention (P < 0.0001). Nearly half (48%) of the CBI participants met the 75% smoking reduction target and one-third (31%) met the abstinence target at week 12. In contrast, none of the NCBI met either the 75% or abstinence targets. Only 2% of the TAU participants met the 75% reduction and none of the TAU participants met the abstinence targets. These smoking behavior reductions did not yield significant differences in birth outcomes.

CONCLUSIONS

Cigarette smoking may be reduced significantly among pregnant, methadone-maintained women through the use of contingent reinforcement for gradual reductions in breath carbon monoxide levels.

Exploring the limits and utility of operant conditioning in the treatment of drug addiction

This article describes a research program to develop an operant treatment for cocaine addiction in low-income, treatment-resistant methadone patients. The treatment's central feature is an abstinence reinforcement contingency in which patients earn monetary reinforcement for providing cocaine-free urine samples. Success and failure of this contingency appear to be an orderly function of familiar parameters of operant conditioning. Increasing reinforcement magnitude and duration can increase effectiveness, and sustaining the contingency can prevent relapse. Initial development of a potentially practical application of this technology suggests that it may be possible to integrate abstinence reinforcement into employment settings using salary for work to reinforce drug abstinence. This research illustrates the potential utility and current limitations of an operant approach to the treatment of drug addiction. Similar research programs are needed to explore the limits of the operant approach and to develop practical applications that can be used widely in society for the treatment of drug addiction.

Alternative reinforcer response cost impacts cocaine choice in humans

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 reinforcer (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.

Parent training plus contingency management for substance abusing families: a Complier Average Causal Effects (CACE) analysis

BACKGROUND

Children of substance abusers are at risk for behavioral/emotional problems. To improve outcomes for these children, we developed and tested an intervention that integrated a novel contingency management (CM) program designed to enhance compliance with an empirically-validated parent training curriculum. CM provided incentives for daily monitoring of parenting and child behavior, completion of home practice assignments, and session attendance.

METHODS

Forty-seven mothers with substance abuse or dependence were randomly assigned to parent training+incentives (PTI) or parent training without incentives (PT). Children were 55% male, ages 2-7 years.

RESULTS

Homework completion and session attendance did not differ between PTI and PT mothers, but PTI mothers had higher rates of daily monitoring. PTI children had larger reductions in child externalizing problems in all models. Complier Average Causal Effects (CACE) analyses showed additional significant effects of PTI on child internalizing problems, parent problems and parenting. These effects were not significant in standard Intent-to-Treat analyses.

CONCLUSION

Results suggest our incentive program may offer a method for boosting outcomes.

A placebo-controlled trial of memantine for cocaine dependence with high-value voucher incentives during a pre-randomization lead-in period

Preclinical findings suggest that the inhibition of NMDA glutamatergic neurotransmission may have beneficial effects in the treatment of cocaine dependence. We hypothesized that memantine, a low potency, uncompetitive NMDA receptor antagonist, would be safe and effective in the treatment of cocaine dependence, particularly in preventing relapse to cocaine use in abstinent individuals. Cocaine dependent patients (N=112) were enrolled. The trial began with a 2-week placebo lead-in period during which patients received high-value voucher contingency management to induce abstinence. Participants were then randomized to receive either memantine 20mg bid (N=39) or placebo (N=42) for 12-weeks in combination with individual relapse-prevention therapy. The randomization was stratified by abstinence status during the lead-in period. The primary outcome was the weekly proportion of days of cocaine use. There were no significant differences in cocaine use outcome between the groups treated with memantine versus placebo. Thus, the efficacy of memantine 40 mg/d for the treatment of cocaine dependence was not supported. Urine-confirmed abstinence during the lead-in period was achieved by 44% of participants, and was a strong predictor of subsequent cocaine abstinence during the trial. This suggests that this clinical trial design, an intensive behavioral intervention during a lead-in period, resolves cocaine dependent patients into two subgroups, one that rapidly achieves sustained abstinence and may not need a medication, and another that displays persistent cocaine use and would most likely benefit from a medication to help induce abstinence. Targeting the latter subgroup may advance medication development efforts.

Contingency management and levodopa-carbidopa for cocaine treatment: a comparison of three behavioral targets

New data support use of levodopa pharmacotherapy with behavioral contingency management (CM) as one efficacious combination in cocaine dependence disorder treatment. A potential mechanism of the combined treatment effects may be related to dopamine-induced enhancement of the saliency of contingently delivered reinforcers. Evidence to support this mechanism was sought by evaluating levodopa-enhancing effects across distinct CM conditions that varied in behavioral targets. A total of 136 treatment-seeking, cocaine dependent subjects participated in this 12-week, randomized, placebo-controlled trial of levodopa (vs. placebo) administered in combination with one of three behavioral CM conditions. In the CM-URINE condition, subjects received cash-valued vouchers contingent on cocaine-negative urine toxicology results. In the CM-ATTEND condition, the same voucher schedule was contingent on attending thrice weekly clinic visits. In the CM-MEDICATION condition, the same voucher schedule was contingent on Medication Event Monitoring Systems- and riboflavin-based evidence of pill-taking behavior. Primary outcomes associated with each CM target behavior were analyzed using generalized linear mixed models for repeated outcomes. CM responding in the CM-ATTEND and CM-MEDICATION conditions showed orderly effects, with each condition producing corresponding changes in targeted behaviors, regardless of medication condition. In contrast, CM responding in the CM-URINE condition was moderated by medication, with levodopa-treated subjects more likely to submit cocaine-negative urines. These findings specify the optimal target behavior for CM when used in combination with levodopa pharmacotherapy.

Comparable efficacy of contingency management for cocaine dependence among African American, Hispanic, and White methadone maintenance clients

Cocaine use is a significant problem among methadone maintenance clients. Contingency management (CM) is a reinforcement-based approach with demonstrated efficacy for reducing cocaine use. This study examines whether the efficacy of CM treatment for cocaine-dependent individuals receiving methadone maintenance for opioid dependence differs by ethnicity. Participants were 191 African American, Hispanic, and White cocaine-dependent methadone maintenance clients, randomly assigned to standard methadone treatment or standard methadone treatment plus CM for 12 weeks. Hispanic participants were younger, less educated, and reported fewer years of cocaine use than did African American and White participants and reported fewer years of heroin use than did African American participants. African American participants were less likely to report a history of psychiatric symptoms or treatment in comparison with Hispanic and White participants. While CM was associated with longer duration of continuous cocaine abstinence and a greater proportion of submitted urine samples negative for cocaine, ethnicity was not related to treatment outcomes, and there was no significant interaction between treatment and ethnicity. CM appears to be an efficacious treatment for cocaine dependence among methadone maintenance clients, regardless of ethnicity. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Effects of oral methamphetamine on cocaine use: a randomized, double-blind, placebo-controlled trial

BACKGROUND

No medication is currently approved for the treatment of cocaine dependence, but several preclinical and clinical reports suggest agonist-like medications, e.g., amphetamine analogues, may be a productive strategy for medication development.

OBJECTIVE

This current proof-of-concept study sought to evaluate the safety, tolerability, and effectiveness of methamphetamine as a candidate treatment for cocaine dependence.

METHODS

A randomized, double-blind, placebo-controlled study served to evaluate three treatment conditions in 82 cocaine-dependent individuals: (1) placebo (0mg, 6x/day; n=27), (2) immediate release (IR) methamphetamine (5mg, 6x/day; n=30), (3) sustained release (SR) methamphetamine (30 mg first pill, 1x/day; 0mg 5x/day; n=25). The study employed a sequential, two-phase design (i.e., 4 weeks of medication and counseling followed by 4 weeks of medication/counseling plus a contingency management procedure).

RESULTS

Both preparation forms of methamphetamine were well-tolerated, with similar retention to placebo (0mg, 33%; 30 mg IR, 30%, 30 mg SR, 32%). Methamphetamine SR was associated with decreased sleep and increased weight loss. Medication adherence rates were high for the first dose of the day (95%), while adherence for subsequent capsules was lower. Those in the SR condition exhibited consistently lower rates of cocaine-positive urine samples (0mg, 60%; 30 mg IR, 66%; 30 mg SR, 29%), p<0.0001, and reported the greatest reduction in craving for cocaine, p<0.05.

CONCLUSIONS

SR methamphetamine significantly reduced cocaine use and craving. Additional research is warranted to develop and evaluate agonist-like medications that may effectively treat cocaine dependence.

Effect of reinforcement probability and prize size on cocaine and heroin abstinence in prize-based contingency management

Although treatment outcome in prize-based contingency management has been shown to depend on reinforcement schedule, the optimal schedule is still unknown. Therefore, we conducted a retrospective analysis of data from a randomized clinical trial (Ghitza et al., 2007) to determine the effects of the probability of winning a prize (low vs. high) and the size of the prize won (small, large, or jumbo) on likelihood of abstinence until the next urine-collection day for heroin and cocaine users (N=116) in methadone maintenance. Higher probability of winning, but not the size of individual prizes, was associated with a greater percentage of cocaine-negative, but not opiate-negative, urines.

Ethnic differences in HIV risk behaviors among methadone-maintained women receiving contingency management for cocaine use disorders

OBJECTIVE

To identify ethnic differences in HIV risk behaviors among cocaine using women receiving methadone maintenance for opioid dependence, and to evaluate the efficacy of contingency management (CM) for cocaine use disorders in reducing HIV risk behaviors.

METHODS

African American (N=47), Hispanic (N=47), and White women (N=29) were randomized to standard methadone treatment or standard methadone treatment plus a CM intervention. They completed the HIV Risk Behavior Scale (HRBS) indicating frequency of drug use and sexual behaviors across the lifetime, in the month before baseline, and in the 3 months following clinical trial participation. Ethnic group differences and the effect of CM on change in HIV risk behaviors between baseline and follow-up were evaluated.

RESULTS

White women reported significantly higher lifetime rates of risky drug use and sexual behaviors on the HRBS than African American women; neither group differed significantly from Hispanic women. No ethnic group differences in HIV risk behaviors were identified in the month prior to baseline. At follow-up, African American women reported fewer high-risk drug use behaviors than White or Hispanic women, and Hispanic women reported more high-risk sexual behaviors than White or African American women. CM was associated with reduction in high-risk drug use behaviors regardless of ethnicity, but did not affect high-risk sexual behaviors.

CONCLUSIONS

White women receiving methadone maintenance engage in more lifetime HIV risk behaviors than African American women. CM for cocaine use reduces risky drug use behaviors, but certain ethnic groups may benefit from additional targeted HIV prevention efforts.

Contingency management reduces injection-related HIV risk behaviors in heroin and cocaine using outpatients

Intravenous drug use is a major vector of HIV transmission. We assessed whether contingency management (CM), in which participants earn reinforcers for drug abstinence, reduces HIV risk behaviors in methadone-maintained opiate- and cocaine-using outpatients. Participants (n=116) were randomly assigned to prize-based CM or to receipt of prize draws noncontingently on a schedule yoked to the CM group. Both groups received methadone and individual counseling throughout treatment. The HIV-Risk Taking Behaviour Scale was administered in written questionnaire form at 2-week intervals (HRBS; [Darke, S., Hall, W., Heather, N., Ward, J., & Wodak, A. (1991). The reliability and validity of a scale to measure HIV risk-taking behaviour among intravenous drug users. AIDS, 5, 181-185]). A mediation analysis was conducted to determine whether abstinence from opiates and cocaine mediated the effect of CM on HRBS scores. Changes in HRBS scores over time differed significantly by treatment (F(9,334)=2.4, p<0.05), with HRBS scores decreasing over time in the CM group to a greater extent than in the noncontingent control group. Participants in the CM group had significantly lower rates of simultaneous cocaine/opiate-positive urine specimens than those in the noncontingent control group during CM treatment (F(1,111)=6.8, p=0.01). The relationship between treatment condition and HRBS scores was mediated by abstinence. CM targeted toward cocaine and heroin use produces significant reductions in injection-related drug-taking behaviors associated with heightened risk for getting or transmitting HIV.

Randomized trial comparing two treatment strategies using prize-based reinforcement of abstinence in cocaine and opiate users

We compared two strategies of prize-based contingency management (CM) in methadone-maintained outpatients. Urine was tested thrice weekly for 5 weeks pre-CM, 12 weeks CM, and 8 weeks post-CM. Participants were randomly assigned to a cocaine contingency (four prize draws for each cocaine-negative urine, N=29) or an opiate-cocaine contingency (one draw for each urine negative for opiates or cocaine, four draws if negative for both, N=38). There were no group differences in cocaine abstinence during CM or post-CM and no differences in opiate abstinence during CM. Opiate abstinence was greater in the opiate-cocaine group post-CM, and heroin craving was reduced in this group during and post-CM. Draws earned per cocaine-negative urine (four vs. one) did not affect cocaine use.

Randomized trial of prize-based reinforcement density for simultaneous abstinence from cocaine and heroin

To examine the effect of reinforcer density in prize-based abstinence reinforcement, heroin/cocaine users (N = 116) in methadone maintenance (100 mg/day) were randomly assigned to a noncontingent control group (NonC) or to 1 of 3 groups that earned prize draws for abstinence: manual drawing with standard prize density (MS) or computerized drawing with standard (CS) or high (CH) density. Probabilities (prizes/draw) were standard (50%) and high (78%); prize density was double blind. Mean prize values were CH, $286; CS, $167; MS, $139; and NonC, $171. Outcomes were % opioid/cocaine-negative urines during the 12-week intervention and then 8 weeks postintervention as well as diagnosis of dependence up to 6 months poststudy. CH had significantly more negative specimens than did NonC during intervention and had more than all groups during postintervention treatment: Mean % negative (95% confidence interval) during postintervention treatment adjusted for baseline drug use and dropout were CH, 55% (14%-90%); CS, 7% (1%-27%); MS, 4% (1%-12%); and NonC, 3% (1%-10%). Current cocaine dependence diagnoses after treatment were significantly lower in contingent compared with noncontingent groups. Computerized drawing with higher-density prizes enhanced reduction of cocaine use; abstinence reinforcement had long-term therapeutic benefits.

Nonreporting of cannabis use: Predictors and relationship to treatment outcome in methadone maintained patients

Underreporting of drug use is common and influenced by multiple factors. Cannabis (THC) use nonreporting and its relationship to heroin and cocaine use were investigated in 690 patients enrolled in 25- to 29-week clinical trials of contingency management plus methadone maintenance. Urine specimens and self-reports of drug use were collected 3 times/week. Potential predictors of THC use nonreporting were analyzed by multiple logistic regression; relationships between THC use nonreporting and % cocaine- and opiate-positive urines were analyzed by multiple regression. Compared to non-THC users (n=317), patients with THC-positive urines (n=373) were more likely to be male and have more years of THC use, but were not different on other characteristics. Nonreporting to user ratios were: THC 191/373 (51.2%); opiates 17/686 (2.5%); cocaine 21/681 (3.1%). Predictors of THC use nonreporting were low rate of THC-positive urines during treatment, fewer days of THC use in the last 30 before treatment, African-American race, and absence of antisocial personality disorder. Nonreporting of THC use was associated with significantly greater opiate and cocaine use. Contingency management decreased cocaine use in THC nonreporters to the level of reporters. Nonreporting of THC use is a significant predictor of greater cocaine and heroin use. This association can be eliminated with contingency management therapy.

A randomized controlled trial of the therapeutic workplace for community methadone patients: a partial failure to engage

The Therapeutic Workplace is an employment-based treatment for drug addiction that uses wages for work to reinforce drug abstinence. The Therapeutic Workplace has promoted abstinence from heroin and cocaine in treatment-resistant mothers in methadone treatment. This study attempted to replicate that effect in crack cocaine users recruited from community-based methadone programs. Participants were randomly assigned to a Therapeutic Workplace (n=22) or usual care control (n=25) group. Therapeutic Workplace participants were invited to work in the workplace and earn vouchers every weekday for 9 months contingent on documented opiate and cocaine abstinence. The two groups did not differ significantly on measures of cocaine or opiate use collected during study participation. Daily attendance and urinalysis results of the Therapeutic Workplace group were analyzed, and only 7 of the 22 participants initiated consistent periods of abstinence and workplace attendance. Two individuals gained access to the workplace on a few days, and 9 participants attempted to gain access to the workplace but never provided a drug-negative urine sample. Possible reasons for differences between the current study and the previous Therapeutic Workplace study are considered. Procedures that increase participant contact with the Therapeutic Workplace and its reinforcement contingencies might increase the likelihood of these individuals being successful in the treatment program.

Contingency Management for Treatment of Substance Abuse

Clinical research trials demonstrate the efficacy of contingency management procedures in treating substance use disorders. Usually, reinforcement, in the form of vouchers exchangeable for retail goods and services, is provided for drug abstinence in patients treated in psychosocial or methadone maintenance clinics. Recently, the types of reinforcers have been adapted to include lower cost alternatives, and reinforcement is being expanded to alter other target behaviors such as attendance at treatment, adherence to treatment goals, and compliance with medication. This chapter provides an overview of the populations and behaviors to which contingency management approaches have been applied. It also reviews design features that appear critical in the successful adaptation of the techniques. In addition, areas for future research are described.

A comparison of voucher-delivery schedules for the initiation of cocaine abstinence

Studies on the use of shaping procedures to increase rates of cocaine abstinence have produced promising results. This study used a Brief Abstinence Test to examine the impact of reinforcement for initial reductions in cocaine use on a subsequent abstinence reinforcement test. Methadone maintenance patients showing evidence of cocaine use were exposed to two 1-week reinforcement conditions. During the shaping condition, participants could earn $50 vouchers on Wednesday and Friday for meeting quantitative urinalysis criteria and a $100 voucher on the following Monday for meeting the more stringent qualitative criteria. During the terminal condition, only the $100 earning opportunity for meeting the qualitative criteria was provided. Participants were more likely to meet the qualitative reinforcement criteria on Wednesday and Friday in the shaping condition than in the terminal condition. However, contrary to the initial hypothesis, the shaping reinforcement condition did not increase rates of abstinence on the final abstinence test.

Prize reinforcement contingency management for cocaine dependence: integration with group therapy in a methadone clinic

In this study, the authors evaluated a low-cost contingency management (CM) procedure for reducing cocaine use and enhancing group therapy attendance in 77 cocaine-dependent methadone patients. Patients were randomly assigned to 12 weeks of standard treatment or standard treatment with CM, in which patients earned the opportunity to win prizes ranging from $1 to $100 for submitting cocainenegative samples and attending therapy. Patients in the CM condition submitted more cocaine-negative samples and attended more groups than patients in standard treatment. The best predictor of cocaine abstinence at follow-up was duration of abstinence during treatment. On average, patients in the CM condition earned $117 in prizes. Data from this study suggest that some aspects of reinforcement can be implemented in group therapy in community-based clinics.

Cocaine abstinence during methadone maintenance: effects of repeated brief exposure to voucher-based reinforcement

This study determined whether abstinence engendered by intermittent reinforcement might generalize to nonreinforced periods and enhance overall rates of cocaine abstinence among methadone maintenance patients. Participants were randomized to 1 of 3 groups. The quantitative group (n = 14) earned incentives for a 50% decrease in urine benzoylecgonine concentrations; the qualitative group (n = 13) earned incentives for providing urines with concentrations <300 ng/ml. Both reinforced groups received 12 random opportunities to earn 100 US dollars in vouchers for abstinence. The control group (n = 15) was encouraged to abstain on 12 occasions under the same schedule. Incentive participants achieved significantly more cocaine abstinence on earning than on nonearning days, with no difference between quantitative and qualitative groups. The study supports brief abstinence test efficacy but did not find that unpredictable opportunities to earn incentives generalized to nonreinforced days.

Clinical Implications of Reinforcement as a Determinant of Substance Use Disorders

Extensive scientific evidence indicates that reinforcement plays an important role in the genesis, maintenance, and recovery from substance use disorders. In this chapter, we review recent clinical research from laboratory, clinic, and naturalistic settings examining the role of reinforcement in substance use disorders. Well-controlled human laboratory studies are reviewed characterizing orderly interactions between the reinforcing effects of drugs and environmental context that have important implications for understanding risk factors for substance use disorders and for the development of efficacious interventions. Recent treatment-outcome studies on voucher-based contingency management and community reinforcement therapy are reviewed demonstrating how reinforcement and related principles can be used to improve outcomes across a wide range of different substance use disorders and populations. Overall, the chapter characterizes a vigorous area of clinical research that has much to contribute to a scientific analysis of substance use disorders.

Reinforcement of counseling attendance and alcohol abstinence in a community-based dual-diagnosis treatment program: A feasibility study

This study evaluated the effectiveness of a community-based contingency management (CM) protocol reinforcing punctual dual-diagnosis group counseling attendance and negative breath alcohol levels. Participants were 20 dual-diagnosis patients. The A-B-A within-subjects reversal design included a 4-week baseline phase (BL), a 12-week CM intervention, and a 4-week return-to-baseline phase (R-BL). Group counseling was provided twice weekly, with breath tests before each session. CM attendance rates were significantly higher (65%+-28%) than BL (45%+-32%, p<.05) and remained elevated in the R-BL phase (68%+-29%). Despite clinical reports of frequent intoxication, during the study all breath test results were negative, regardless of study phase. Thus, no contingency effect on alcohol use could be determined. Results suggest that CM interventions can be effective in increasing attendance in a community treatment program for the dually diagnosed.

Cognitive-behavioral therapy plus contingency management for cocaine use: findings during treatment and across 12-month follow-up

Contingency management (CM) rapidly reduces cocaine use, but its effects subside after treatment. Cognitive-behavioral therapy (CBT) produces reductions months after treatment. Combined, the 2 might be complementary. One hundred ninety-three cocaine-using methadone-maintained outpatients were randomly assigned to 12 weeks of group therapy (CBT or a control condition) and voucher availability (CM contingent on cocaine-negative urine or noncontingent). Follow-ups occurred 3, 6, and 12 months posttreatment. Primary outcome was cocaine-negative urine (urinalysis 3 times/week during treatment and once at each follow-up). During treatment, initial effects of CM were dampened by CBT. Posttreatment, there were signs of additive benefits, significant in 3- versus 12-month contrasts. Former CBT participants were also more likely to acknowledge cocaine use and its effects and to report employment.

Does cannabis use predict poor outcome for heroin-dependent patients on maintenance treatment? Past findings and more evidence against

AIMS

To determine whether cannabinoid-positive urine specimens in heroin-dependent out-patients predict other drug use or impairments in psychosocial functioning, and whether such outcomes are better predicted by cannabis-use disorders than by cannabis use itself.

DESIGN

Retrospective analyses of three clinical trials; each included a behavioral intervention (contingency management) for cocaine or heroin use during methadone maintenance. Trials lasted 25-29 weeks; follow-up evaluations occurred 3, 6 and 12 months post-treatment. For the present analyses, data were pooled across trials where appropriate.

SETTING

Urban out-patient methadone clinic.

PARTICIPANTS

Four hundred and eight polydrug abusers meeting methadone-maintenance criteria.

MEASUREMENTS

Participants were categorized as non-users, occasional users or frequent users of cannabis based on thrice-weekly qualitative urinalyses. Cannabis-use disorders were assessed with the Diagnostic Interview Schedule III-R. Outcome measures included proportion of cocaine- and opiate-positive urines and the Addiction Severity Index (at intake and follow-ups).

FINDINGS

Cannabis use was not associated with retention, use of cocaine or heroin, or any other outcome measure during or after treatment. Our analyses had a power of 0.95 to detect an r2 of 0.11 between cannabis use and heroin or cocaine use; the r2 we detected was less than 0.03 and non-significant. A previous finding, that cannabis use predicted lapse to heroin use in heroin-abstinent patients, did not replicate in our sample. However, cannabis-use disorders were associated weakly with psychosocial problems at post-treatment follow-up.

CONCLUSIONS

Cannabinoid-positive urines need not be a major focus of clinical attention during treatment for opiate dependence, unless patients report symptoms of cannabis-use disorders.

Voucher-based incentives. A substance abuse treatment innovation

In this report we provide an overview of research on the voucher-based incentives approach to substance abuse treatment. This approach was originally developed as a novel method for improving retention and increasing cocaine abstinence among cocaine-dependent outpatients. The efficacy of vouchers for those purposes is now well established, and plans are underway to move the intervention into effectiveness testing in community clinics. The use of vouchers also has been extended to the treatment of alcohol, marijuana, nicotine, and opioid dependence. Particularly noteworthy is that vouchers hold promise as an efficacious intervention with special populations of substance abusers, including pregnant and recently postpartum women, adolescents, and those with serious mental illness. Overall, voucher-based incentives hold promise as an innovative treatment intervention that has efficacy across a wide range of substance abuse problems and populations.

Abstinence reinforcement maintenance contingency and one-year follow-up

BACKGROUND

Relapse to drug use is often seen when contingencies designed to reduce drug use are discontinued. This paper reports on a stepdown maintenance contingency and 1-year follow-up in 110 patients who were maintained on methadone (50 or 70 mg/day) and who had completed a contingency management trial targeted to decreasing their opiate use. In the prior study (induction phase, 8 weeks) participants received vouchers for each opiate-negative urine screen or noncontingently.

METHODS

In this study (maintenance phase, 12 weeks), participants were rerandomized to receive vouchers and take-home methadone doses contingent on providing opiate-negative urine specimens (N=55) or noncontingently (N=55). Since participants had been rerandomized from induction-phase contingencies, most study data were analyzed as if from a 2 x 2 (inductionxmaintenance) design. Follow-up interviews were conducted at 3, 6, and 12 months after study participation.

RESULTS

Patients who received the maintenance contingency following an 8-week induction contingency had better outcomes than those who received noncontingent incentives in either the maintenance or induction phases of the trial. Good outcome at follow-up was predicted by enrollment in methadone maintenance after the study. Significantly more participants in the maintenance contingency group transferred directly to another methadone program.

CONCLUSION

These findings support the therapeutic value of extending the duration of contingency management and long-term methadone maintenance.