A randomized trial of employment-based reinforcement of cocaine abstinence in injection drug users

High-magnitude and long-duration abstinence reinforcement can promote drug abstinence but can be difficult to finance. Employment may be a vehicle for arranging high-magnitude and long-duration abstinence reinforcement. This study determined if employment-based abstinence reinforcement could increase cocaine abstinence in adults who inject drugs and use cocaine during methadone treatment. Participants could work 4 hr every weekday in a workplace where they could earn about $10.00 per hour in vouchers; they were required to provide routine urine samples. Participants who attended the workplace and provided cocaine-positive urine samples during the initial 4 weeks were invited to work 26 weeks and were randomly assigned to an abstinence-and-work (n = 28) or work-only (n = 28) group. Abstinence-and-work participants had to provide urine samples showing cocaine abstinence to work and maintain maximum pay. Work-only participants could work independent of their urinalysis results. Abstinence-and-work participants provided more (p = .004; OR = 5.80, 95% CI = 2.03-16.56) cocaine-negative urine samples (29%) than did work-only participants (10%). Employment-based abstinence reinforcement can increase cocaine abstinence.     

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.     

Attendance Rates in A Workplace Predict Subsequent Outcome of Employment-Based Reinforcement of Cocaine Abstinence in Methadone Patients

This study assessed whether attendance rates in a workplace predicted subsequent outcome of employment-based reinforcement of cocaine abstinence. Unemployed adults in Baltimore methadone programs who used cocaine (N  =  111) could work in a workplace for 4 hr every weekday and earn $10.00 per hour in vouchers for 26 weeks. During an induction period, participants provided urine samples but could work independent of their urinalysis results. After the induction period, participants had to provide urinalysis evidence of cocaine abstinence to work and maintain maximum pay. A multiple regression analysis showed that induction period attendance was independently associated with urinalysis evidence of cocaine abstinence under the employment-based abstinence reinforcement contingency. Induction period attendance may measure the reinforcing value of employment and could be used to guide the improvement of employment-based abstinence reinforcement.     

CONTINGENT REINFORCEMENT OF ABSTINENCE WITH INDIVIDUALS ABUSING COCAINE AND MARIJUANA

Two males diagnosed with cocaine dependence received a behavioral intervention comprised of contingency management and the community reinforcement approach. During the initial phase of treatment, reinforcement was delivered contingent on submitting cocaine-free urine specimens. The community reinforcement approach involved two behavior therapy sessions each week. Almost complete cocaine abstinence was achieved, but regular marijuana use continued. During a second phase, reinforcement magnitude was reduced, but remained contingent on submitting cocaine-free specimens. Behavior therapy was reduced to once per week. Cocaine abstinence and regular marijuana use continued. Next, reinforcement was delivered contingent on submitting cocaine- and marijuana-free specimens. This modified contingency resulted in an abrupt increase in marijuana abstinence and maintenance of cocaine abstinence. One- and 5-month follow-ups indicated that cocaine abstinence continued, but marijuana smoking resumed. These results indicate that the behavioral intervention was efficacious in achieving abstinence from cocaine and marijuana; maintenance, however, was achieved for cocaine only.     

Effects of pay resets following drug use on attendance and hours worked in a therapeutic workplace

This secondary data analysis examined effects of an abstinence contingency on participation in a therapeutic workplace. Participants exposed to a pay reset after drug use did not differ in overall attendance from participants who were not exposed to a pay reset after drug use; however, they initially worked less after a pay reset than participants who did not receive a pay reset, and their attendance increased as their pay increased. Overall participation was not influenced by the abstinence contingency, but transient decreases in attendance occurred.     

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.     

Repeated post- or presession cocaine administration: roles of dose and fixed-ratio schedule

Effects of repeated administration of cocaine to animals behaving under operant contingencies have depended on when the drug is given. Moderate doses given presession have generally led to a decrease in the drug's effect, an outcome usually referred to as tolerance. When these same doses have been given after sessions, the usual result has been no change or an increase in the drug's effects, with the latter usually referred to as sensitization. In the present study, repeated postsession administration of a relatively small dose of cocaine (3.0 or 5.6 mg/kg) to pigeons responding under a multiple fixed-ratio 5, fixed-ratio 100 schedule of food presentation generally resulted in tolerance to the rate-decreasing effects of the drug. When the same dose was given before sessions, little additional tolerance was observed, although some subjects showed further tolerance in the small-ratio component. A regimen of repeated postsession injection of larger (10.0-23.0 mg/kg) doses suppressed key pecking during the session; responding resumed following discontinuation of postsession administrations. Effects of postsession administration of cocaine, therefore, depended on the dose, with smaller doses leading to tolerance and larger ones to suppression of behavior during the session. Effects of postsession drug administration of either small or large doses were not related to whether effects of postsession drug were experienced mainly in the operant test chamber or in the pigeon's home cage. The results with large postsession doses are compatible with a view that the drug acted as a Pavlovian unconditional stimulus, with the session-related stimuli acting as a long-duration Pavlovian conditional stimulus. Tolerance following postsession administration of the smaller doses challenges the view that it depended on experiencing the drug's effects while the arranged reinforcement contingencies were in effect.     

Prospective relationships between drug problems and work adjustment in a community sample of adults

The prospective relationships between drug problems and work adjustment (e.g., job instability, job satisfaction) were examined in a community sample of 470 adults. Polydrug problems (alcohol, marijuana, and cocaine problem drug use) were both predictors and consequences of work adjustment. In partial support of the impaired functioning theory, polydrug problems predicted reduced job satisfaction 4 years later. Supporting the work-related strain theory, early job instability predicted polydrug problems 4 years later. In support of the theory of general deviance, low social conformity predicted later job instability. Finally, supporting social support theory, early support for drug problems reduced polydrug problems and increased job satisfaction 4 years later.     

HIV prevention among drug users: outcome of a network-oriented peer outreach intervention.

A network-oriented HIV prevention intervention based on social identity theory and peer outreach was implemented for HIV positive and negative drug users. A community sample of 250 were randomly assigned to an equal-attention control condition or a multisession, small-group experimental condition, which encouraged peer outreach; 94% of participants were African American, and 66% used cocaine or opiates. At follow-up, 92% of participants returned, and experimental compared with control group participants were 3 times more likely to report reduction of injection risk behaviors and 4 times more likely to report increased condom use with casual sex partners. Results suggest that psychosocial intervention emphasizing prosocial roles and social identity, and incorporating peer outreach strategies, can reduce HIV risk in low-income, drug-using communities.     

Interdependent Group Contingency Management for Cocaine-Dependent Methadone Maintenance Patients

Contingency management (CM) for drug abstinence has been applied to individuals independently even when delivered in groups. We developed a group CM intervention in which the behavior of a single, randomly selected, anonymous individual determined reinforcement delivery for the entire group. We also compared contingencies placed only on cocaine abstinence (CA) versus one of four behaviors (CA, treatment attendance, group CM attendance, and methadone compliance) selected randomly at each drawing. Two groups were formed with 22 cocaine-dependent community-based methadone patients and exposed to both CA and multiple behavior (MB) conditions in a reversal design counterbalanced across groups for exposure order. The group CM intervention proved feasible and safe. The MB condition improved group CM meeting attendance relative to the CA condition.     

Cocaine use and post partum psychiatric symptoms.

The association of mental health symptoms with cocaine use was studied among post partum women. Gestational cocaine use was determined by confidential interview or urine assay. A structured Psychiatric Symptom Index was used to measure mental health symptoms. Among 155 women, 24 (15%) used cocaine. Cocaine-using women had less education, higher parity, less weight gain during pregnancy, and used more cigarettes, marijuana, and opiates in pregnancy than nonusers. High frequency of symptoms (standardized Psychiatric Symptom Index score greater than or equal to 20) was found in 71% of women for the Total Index score, 81% on depression, 61% on anxiety, 36% on cognitive disturbance, and 75% on anger. No differences in Psychiatric Symptom Index Total or factor scores were associated with cocaine use.     

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.     

Activation of amygdaloid PKC pathway is necessary for conditioned cues-provoked cocaine memory performance

Drug-associated cues are critical in reinstating the drug taking behavior even during prolonged abstinence and thus are thought to be a key factor to induce drug craving and to cause relapse. Amygdaloid complex has been known for its physiological function in mediating emotional experience storage and emotional cues-regulated memory retrieval. This study was undertaken to examine the role of basolateral nuclei of amygdala and the intracellular signaling molecule in drug cues-elicited cocaine memory retrieval. Systemic anisomycin treatment prior to the retrieval test abolished the cues-provoked cocaine conditioned place preference (CPP) memory. Likewise, a similar blockade of cues-provoked cocaine CPP performance was achieved by infusion of anisomycin and cycloheximide into the basolateral nuclei of amygdala before the test. Intra-amygdaloid infusion of H89, a protein kinase A inhibitor, or U0126, a MEK inhibitor, did not affect retrieval of the cues-elicited cocaine CPP memory. In contrast, intra-amygdaloid infusion of NPC 15437, a PKC inhibitor, abolished the cues-elicited cocaine CPP expression, while left the memory per se intact. Intra-amygdaloid infusion of NPC 15437 did not seem to affect locomotor activity or exert observable aversive effect. Taken together, our results suggest that activation of PKC signaling pathway and probably downstream de novo protein synthesis in the basolateral nuclei of amygdala is required for the cues-elicited cocaine memory performance. However, temporary inhibition of this signaling pathway does not seem to affect cocaine CPP memory per se.     

Religiosity and HIV-Related Drug Risk Behavior: A Multidimensional Assessment of Individuals from Communities with High Rates of Drug Use

We examined the relationship between religiosity and HIV-related drug risk behavior among individuals from communities with high rates of drug use who participated in the SHIELD (Self-Help in Eliminating Life-Threatening Disease) study. This analysis examined the dimensions of religious ideation, religious participation, and religious support separately to further understand the relationship with risk taking. Results indicate that greater religious participation appeared to be the dimension most closely associated with drug behaviors. Specifically, we found that those with greater religious participation are significantly less likely to report recent opiates or cocaine use; injection drug use; crack use; and needle, cotton or cooker sharing. Future work to understand the nature of these associations will assist in the development of interventions in communities with high rates of drug use.     

Relationships between adolescent drug use and parental drug behaviors

The present study examined some previously reported relationships between drug use by adolescents and perceived attitudes and behaviors of their parents. An anonymous questionnaire was administered to the student body of an inner-city secondary school for difficult students. Relationships between parental use of drugs and adolescent use of the same drugs were moderate and roughly equivalent across drugs. However, parental use of marijuana was strongly related to the adolescent's use of other, harder drugs such as opiates, cocaine, amphetamines, and barbiturates. This finding is explained within the framework of Kandel's postulated stages of drug initiation. It points to a need for further study of parental influences, which may be increasingly problematic as more individuals who have grown up in our marijuana-accepting society become parents of adolescents.     

Individual characteristics and response to Contingency Management treatment for cocaine addiction

Voucher-based contingency management (CM) research has demonstrated efficacy for treating cocaine addiction, but few studies have examined associations between individual baseline characteristics and response to CM treatments. The aim of this study, involving 50 cocaine outpatients receiving CM for cocaine addiction, was to assess the impact of baseline characteristics on abstinence outcomes after six months of treatment. Patients who were abstinent after six months of treatment accounted for 58% of the sample. Patients with higher scores on the Alcohol area of the EuropASI and patients that were non-abstinent during the first month of treatment were less likely to achieve abstinence. These outcome predictors have implications both for treatment research and for clinical practice. Patients who do not respond early to treatment may need a more intensive intervention, and concomitant problematic alcohol use should be detected and treated. The remaining baseline variables examined were not statistically significant predictors of abstinence. This finding is important for the generalizability of CM across the range of individual characteristics of treatment-seeking cocaine abusers.     

Neuronal substrates of relapse to cocaine-seeking behavior: role of prefrontal cortex

The return to drug seeking, even after prolonged periods of abstinence, is a defining feature of cocaine addiction. The neural circuitry underlying relapse has been identified in neuropharmacological studies of experimental animals, typically rats, and supported in brain imaging studies of human addicts. Although the nucleus accumbens (NAcc), which has long been implicated in goal-directed behavior, plays a critical role in this circuit, the prefrontal cortex (PFC) appears to process the events that directly trigger relapse: exposure to acute stress, cues previously associated with the drug, and the drug itself. In this paper, we review animal models of relapse and what they have revealed about the mechanisms underlying the involvement of the NAcc and PFC in cocaine-seeking behavior. We also present electrophysiological data from PFC illustrating how the hedonic, motor, motivational, and reinforcing effects of cocaine can be analyzed at the neuronal level. Our preliminary findings suggest a role for PFC in processing information related to cocaine seeking but not the hedonic effects of the drug. Further use of this recording technology can help dissect the functions of PFC and other components of the neural circuitry underlying relapse.     

Effect of incentives on retention in an outpatient treatment for cocaine addicts

The high drop-out rate in treatment programs is one of the most important problems in the area of drug addictions. This study evaluated the effect of the use of incentives on retention in an outpatient program for cocaine addicts. The effect of individual variables on program drop-out was also analysed. Participants were 66 subjects who were randomly assigned to one of three treatment groups: standard treatment, treatment with incentives I, and treatment with incentives II. The patients of these two groups received incentives contingent on cocaine abstinence with two different magnitudes. Retention rate at six months was 35% in the standard treatment, 78.6% in the treatment with incentives I, and 53.3% in the treatment with incentives II. The global prognostic capacity of the individual variables (sociodemographic, history and consumption pattern, psychopathological variables, and EuropASI scores) was 85.7%, with the psychopathological variables being more closely related to retention. These results suggest that the use of incentives may be an effective strategy to improve retention in outpatient treatments for cocaine addiction.     

Discrimination of methadone and cocaine by pigeons without explicit discrimination training.

Pigeons were trained to peck a key on a variable-interval 2-min schedule of food reinforcement. Prior to each session, either 2.0 mg/kg methadone (n = 3), 3.0 mg/kg cocaine (n = 4), or 5.6 mg/kg cocaine (n = 2) was administered. When each pigeon's rate of pecking was stable, a range of doses of the training drug and saline were administered prior to 20-min extinction sessions separated by at least four training sessions. Rate of pecking during these extinction tests was generally an increasing function of dose, with the lowest rates obtained following saline and low doses and the highest rates obtained following doses near the training doses. Dose functions from pigeons trained with 5.6 mg/kg cocaine were steeper than those from pigeons trained with 3.0 mg/kg cocaine. Pigeons trained with methadone or 3.0 mg/kg cocaine were then given discrimination training, in which food reinforcement followed drug administration and 20-min extinction sessions followed saline administration. Rates of pecking under these conditions quickly diverged until near-zero rates were obtained following saline and high rates were obtained following drug. Discrimination training steepened dose functions for the training drugs, and the effects of several other substituted drugs depended on the pharmacology of the training drug. The pigeons trained with 5.6 mg/kg cocaine were tested with d-amphetamine, methadone, and morphine prior to discrimination training. d-Amphetamine increased rates dose dependently, and methadone and morphine did not. The results suggest that discriminative control by methadone and cocaine was established without explicit discrimination training.     

Addiction motivation reformulated: an affective processing model of negative reinforcement

This article offers a reformulation of the negative reinforcement model of drug addiction and proposes that the escape and avoidance of negative affect is the prepotent motive for addictive drug use. The authors posit that negative affect is the motivational core of the withdrawal syndrome and argue that, through repeated cycles of drug use and withdrawal, addicted organisms learn to detect interoceptive cues of negative affect preconsciously. Thus, the motivational basis of much drug use is opaque and tends not to reflect cognitive control. When either stressors or abstinence causes negative affect to grow and enter consciousness, increasing negative affect biases information processing in ways that promote renewed drug administration. After explicating their model, the authors address previous critiques of negative reinforcement models in light of their reformulation and review predictions generated by their model.