Alcohol pretreatment increases preference for cocaine over monetary reinforcement.

Non-dependent cocaine users participated in a two-phase experiment conducted under controlled laboratory conditions. During phase 1, subjects sampled intranasal cocaine (100 mg) and placebo (96 mg lactose + 4 mg cocaine) in separate sessions and under double-blind conditions. Sampling sessions were followed by a single choice session in which subjects made a maximum of ten choices between 10 mg unit doses of cocaine or placebo. Only subjects who reliably (> or = 70%) chose cocaine over placebo in phase 1 participated in phase 2. During phase 2, subjects participated in a series of nine experimental sessions conducted on different days in which they were pretreated with varying doses of alcohol (placebo, 0.5, and 1.0 g/kg) and made a maximum of ten choices between 10 mg unit doses of cocaine and an alternative reinforcer (i.e., varying amounts of money). Visual-analog ratings of drug effects and cardiac function were monitored across all experimental sessions. Cocaine was reliably chosen over placebo by the majority (9 of 11) of subjects during phase 1, demonstrating that the drug functioned as a reinforcer. During phase 2, alcohol pretreatment significantly increased choice of cocaine over the alternative reinforcer, while increasing monetary value decreased cocaine choice. Ratings on some visual-analog scales (e.g., good effects) paralleled cocaine choice, with alcohol pretreatment increasing ratings and greater monetary value decreasing them. Cardiac output increased above baseline levels across all alcohol and monetary conditions, but maximal effects were observed during sessions involving pretreatment with the active alcohol doses. Overall, these results demonstrate (a) that alcohol can increase preference for cocaine over alternative reinforcers and thereby may thwart efforts to reduce or abstain from cocaine use, (b) that availability of an alternative, non-drug reinforcer can effectively decrease preference for cocaine, and (c) that combined use of alcohol and cocaine increases cardiac risk compared to use of cocaine alone.

Tolerance-like attenuation to contingent and noncontingent cocaine-induced elevation of extracellular dopamine in the ventral striatum following 7 days of withdrawal from chronic treatment.

Time-dependent changes in mesolimbic dopamine (DA) function are believed to play a role in behavioral sensitization and drug craving experienced during withdrawal from chronic cocaine administration. The present study utilized intravenous (IV) cocaine self-administration coupled with intracranial microdialysis in rats to investigate time dependent changes during withdrawal from chronic cocaine exposure. Following 2 weeks of IV cocaine self-administration, rats were allowed contingent access to cocaine at 1 and 7 days of withdrawal while extracellular levels of DA were measured from the ventral striatum. A second group of animals received yoked, noncontingent cocaine for 2 weeks and were then administered noncontingent cocaine on days 1 and 7 of withdrawal. In addition, a third group of animals received 2 weeks of yoked saline followed by noncontingent cocaine 1 day after withdrawal. There were no significant differences between groups for the overall cocaine dosage or temporal pattern of infusions on days 1 and 7 of withdrawal. Basal extracellular DA concentrations did not differ between any treatment groups at either withdrawal time. Extracellular DA levels were increased throughout the session on both days; however, the increases at day 7 were significantly less than day 1 for both contingent and noncontingent conditions. DA overflow on day 1 did not differ between animals receiving chronic yoked cocaine or saline. These results suggest that tolerance-like attenuation to the DA-elevating effects of cocaine is not apparent early in withdrawal, but does develop by later time points.(ABSTRACT TRUNCATED AT 250 WORDS)

A within-subject comparison of three different schedules of reinforcement of drug abstinence using cigarette smoking as an exemplar.

In this experiment we compared three different schedules of reinforcement for promoting and sustaining short-term drug abstinence. For pragmatic reasons, cigarette smoking was studied as an exemplar of drug self-administration. The three schedules studied were a fixed magnitude of reinforcement for abstinence, a progressive increase in magnitude of reinforcement for abstinence with a reset contingency for drug use, and a progressive increase in magnitude of reinforcement for abstinence without a reset contingency. Eighteen cigarette smokers experienced the three schedules in a counterbalanced order. Each schedule was in effect for 5 consecutive days (M-F), during which time abstinence was reinforced according to the different schedules of reinforcement. The total amount of reinforcement (money) available was the same during each condition. The progressive magnitude with a reset schedule was more effective than the other two schedules in sustaining an initial period of abstinence. These results systematically replicate and extend those from prior studies demonstrating the efficacy of schedules incorporating a progressively increasing magnitude of reinforcement with a reset contingency for sustaining initial drug abstinence, and demonstrate the importance of the reset contingency to that effect.

A comparison of cocaine-dependent cigarette smokers and non-smokers on demographic, drug use and other characteristics.

Cigarette smoking (n = 156) and non-smoking (n = 43) individuals seeking out-patient treatment for cocaine-dependence were compared on demographic, drug use and other variables. Smokers were younger, less educated, earned less money, began cocaine use at an earlier age, used cocaine more frequently, were more likely to inject or smoke cocaine, were more likely to report legal troubles and having harmed someone physically as consequences of their cocaine use, and had more severe employment and legal problems than non-smokers as measured by the Addiction Severity Index. Smoking remained a significant predictor of more frequent cocaine use, using more grams of cocaine per week and using cocaine via an injection or smoking route even after adjusting for demographic differences between smokers and non-smokers via regression analyses. Smoking status was not significantly related to treatment outcome. Overall, these results indicate that cocaine-dependent smokers represent a more high-risk group than non-smokers. This relationship between smoking, cocaine use, and associated problems merits further investigation.

Impulsivity and voucher versus money preference in polydrug-dependent participants enrolled in a contingency-management-based substance abuse treatment program.

Thirty-four polydrug-dependent participants enrolled in a voucher-based substance abuse treatment program were given choices between hypothetical amounts of money and hypothetical amounts of vouchers, which are traded for goods and services, to determine their preferences for the two payment modalities. It was hypothesized that the majority of participants would prefer money to voucher because under the circumstances of the treatment program, the delay associated with money exchange is shorter than the delay associated with voucher exchange. It was further hypothesized that those participants who selected money over voucher also would have greater levels of impulsivity as assessed by the Barratt Impulsiveness Rating Scale (BIS) (Barratt, 1965). The results show large individual differences in money/voucher preference with approximately half of the participants preferring money to voucher when the two amounts are equivalent. In addition, as the magnitude of the money/voucher comparisons increased from 0.50 dollars to 32.00 dollars, the percentage of participants that preferred money increased. No correlations were found between money/voucher preference and impulsivity scores.

Cocaine use can increase cigarette smoking: evidence from laboratory and naturalistic settings.

Two studies examined the effects of cocaine use on cigarette smoking. Study 1 was conducted with 10 healthy volunteers under controlled laboratory conditions. Participants received double-blind doses of intranasal cocaine HCl (100 mg) or placebo in separate sessions, with each being followed by a 3-hr period of monitored cigarette smoking. Latency to the first cigarette and the mean interval between cigarettes was significantly shorter and the total number of cigarettes smoked was greater after cocaine than placebo administration. Study 2 was conducted by using urine specimens from 9 ambulatory cocaine-dependent patients. Urine cotinine (nicotine metabolite) levels on days when urinalysis testing indicated recent cocaine use were compared with levels on days when urinalysis testing indicated no recent use. Cotinine levels were significantly higher on cocaine-positive days, indicating that cocaine use was associated with greater cigarette smoking. Overall results provide evidence that acute cocaine administration can increase cigarette smoking.

The influence of exchange delays on cigarette versus money choice: a laboratory analog of voucher-based reinforcement therapy.

Contingency-management interventions that provide reinforcement in the form of exchangeable vouchers, contingent on drug abstinence, are among the most effective substance abuse treatment strategies available. Factors known to contribute to the efficacy of these interventions include voucher magnitude and the schedule with which vouchers are made available. Another potential factor may be the delay between earning a voucher and exchanging it for a desired good or service. The authors adapted a laboratory analog of a voucher program to examine the effects of immediacy of reinforcement and its interaction with reinforcer magnitude. Abstinent cigarette smokers made repeated choices between puffs on a cigarette and points worth a variety of monetary values (10 cents-2 dollars). The time at which these points could be exchanged for money varied from the end of the session to 1 or 3 weeks. Results indicated that longer exchange delays and tower magnitude reinforcers increased the number of choices for drug.

Use of monetary reinforcement to reduce the cigarette smoking of persons with schizophrenia: a feasibility study.

The feasibility of using monetary reinforcement to promote abstinence from substance use in adult individuals with schizophrenia was addressed. Cigarette smoking was studied as an exemplar of drug use in 11 individuals with schizophrenia by use of a within-subject experimental design. The study duration was 3 weeks, with weeks 1 and 3 serving as baseline conditions and week 2 serving as the intervention condition; in the latter, patients could earn money by abstaining from cigarette smoking. Abstinence was significantly greater during the intervention condition than during the baseline conditions. These results illustrate the potential sensitivity of drug use in this population to reinforcement contingencies, suggesting that contingency-management interventions are a feasible option for treating the substance abuse of individuals with schizophrenia.

Contingency management interventions for treating the substance abuse of adolescents: a feasibility study.

This article reports on the feasibility of using a contingency management intervention with adolescent smokers that has proven efficacious in adult substance abuse treatment. The study used 8 adolescent participants in an A (1 week)-B (1 week)-A (1 week) reversal design. During the 2 baseline phases, no contingencies were placed on cigarette smoking, and adolescents received money noncontingently. During the experimental intervention week, adolescents received payment contingent on not smoking. The magnitude of reimbursement available during the baseline and intervention phases was equated. Results indicated that the contingency management intervention was effective in reducing smoking, both in terms of increasing the total number of abstinences and consecutive abstinences. In addition, changes in adolescents' affective states during smoking cessation were found. Anxiety, depression, anger, and fatigue were reported, and these negative states ceased once smoking resumed.

The effect of olfactory and auditory stimuli on drinking suppressed with a conditioned taste aversion.

Two studies were conducted to assess the effect of auditory and olfactory stimuli on drinking that had been suppressed with a conditioned taste aversion procedure. Each study used a different conditioned stimulus. The first used an 8% saccharin solution which was readily consumed by rats, while the second used a 1% anise solution that was not as readily consumed by rats. The use of a relatively palatable conditioned stimulus and an unpalatable conditioned stimulus allows for an examination of any effect amount of consumption prior to conditioning might have. The results indicated that the stimuli increased drinking suppressed with a conditioned taste aversion in both studies and drinking by control rats in Experiment 2. In Experiment 1 the stimuli either had no effect or suppressed drinking in the control rats. These results indicate that low levels of drinking can under some circumstances, be increased via the presentation of olfactory or auditory stimuli. They further suggest that deflation of drinking from a high to a low rate is not necessary to observe this effect.

Knowledge of session length is a determinant of within-session response patterns in a human operant paradigm.

Two experiments were conducted during which undergraduates responded during a variable-interval (VI) 60-second operant task. The first experiment consisted of either three 60-minute sessions or three 30-minute sessions. During Experiment 1 subjects were informed as to the length of the session and the number of sessions that would be conducted. During the second experiment subjects were told that they would be participating in three 60-minute sessions but they actually participated in one 30-minute session. During Experiment 1 the rate of responding increased significantly within the sessions for 30-minute sessions but did not change significantly for 60-minute sessions. Response rate did not change during the 30-minute session in Experiment 2. The results of these experiments demonstrate that, under certain circumstances, rate of responding changes within-sessions for humans. The experiments also provide some evidence that a prospective factor influences the rate of responding within an experimental session for human subjects.

A preliminary examination of some effects of cocaine on within-session patterns of responding.

Two experiments examined within-session changes in operant responding when cocaine or cocaine plus food served as the reinforcer. In Experiment 1, male rats self-administered intravenous cocaine according to several fixed interval schedules. The within-session patterns of responding differed for the different schedules early in the session, but they converged by 50 minutes into the session. Because this convergence occurred regardless of the amount of cocaine consumed, it questions the response-stereotypy and dopamine-loading explanations for within-session changes in responding for cocaine reinforcers. In Experiment 2, rats responded for sweetened condensed milk during baseline sessions. During experimental sessions, responding produced cocaine in addition to the condensed milk. The addition of cocaine altered the pattern of responding during the early (first 15 minutes), but not the later (last 45 minutes), parts of the session. These results suggest that different factors produce the early-session increases and late-session decreases in responding. They are also consistent with the idea that the early-session changes in responding represent changes in'arousal'.

Responding changes systematically within sessions during conditioning procedures.

When the procedure is held constant within an experimental session, responding often changes systematically within that session. Many of these within-session changes in responding cannot be dismissed as learning curves or by-products of satiation. They have been observed in studies of positive reinforcement, avoidance, punishment, extinction, discrimination, delayed matching to sample, concept formation, maze and alley running, and laboratory analogues of foraging, as well as in the unconditioned substrates of conditioned behavior. When aversive stimuli are used, responding usually increases early in the session. When positive reinforcers are used, responding changes in a variety of ways, including increasing, decreasing, and bitonic functions. Both strong and minimal reinforcement procedures produce within-session decreases in positively reinforced behavior. Within-session changes in responding have substantial theoretical and methodological implications for research in conditioning.

Within-session changes in responding during several simple schedules.

Pigeons' key pecking was reinforced by food delivered by several fixed-interval, variable-ratio, and differential-reinforcement-of-low-rate schedules. Rate of responding, number of responses per reinforcer, length of postreinforcement pause, running response rate, and the time required to collect an available reinforcer changed systematically within sessions when the schedules provided high rates of reinforcement, but usually not when they provided low rates. These results suggest that the factors that produce within-session changes in responding are generally similar for different schedules of reinforcement. However, a separate factor may also contribute during variable-ratio schedules. The results question explanations for within-session changes that are related solely to the passage of time, to responding, and to one interpretation of attention. They support the idea that one or more factors related to reinforcement play a role.

An experimental comparison of three different schedules of reinforcement of drug abstinence using cigarette smoking as an exemplar.

The efficacy of three different schedules of reinforcement for promoting and sustaining drug abstinence was compared in this study. Cigarette smoking was studied as an exemplar of stimulant drug self-administration. Sixty cigarette smokers were assigned to one of three groups (progressive rate of reinforcement, fixed rate of reinforcement, and yoked control). Participants in all three groups were asked to refrain from smoking for 1 week. Participants in the progressive and fixed groups achieved greater mean levels of abstinence than those in the control group. Participants in the progressive group were significantly less likely to resume smoking when they became abstinent than participants in the other groups.

A behavioral approach to understanding and treating pathological gambling.

This report provides a behavioral account of gambling and its treatment. It describes the similarities between gambling and other behaviors maintained by intermittent schedules of reinforcement, the relationship between response cost and gambling behaviors, and how magnitudes of reinforcers affect gambling behaviors. In addition, the relationship between immediacy of reinforcement and behavior is described. Using these behavioral phenomena, behavioral and cognitive-behavioral treatments of pathological gambling are described. Finally, we present the rationale and framework for our cognitive-behavioral treatment, and we provide a behavioral interpretation of 12-step groups.