Decision-making in long-term cocaine users: Effects of a cash monetary contingency on Gambling task performance

Drug Use Control Perception and Strategies in General and Clinical Population in a Spanish City

Background: This article evaluates the perception of drug use control and strategies in Valencia City (Spain) in a general and clinical population, in two independent studies. Material and Methods: 1071 people participated. In Study 1 (n = 924) the entire sample came from the general population (GP), and in Study 2 (n = 147), 68 were drug users being treated in an Addictive Behavior Unit (ABU), and 79 people of the GP. The drug use control perception and strategies in both subgroups were compared. The participants filled in the Drug Use Strategies Scale and a Drug Use Survey. Results: A high level of perception of drug control in the GP was obtained (72.7% in Study 1 and 67.5% in Study 2), and 32.5% in the ABU subgroup. People in the GP and drug users in treatment differ in some control strategies. A predictive profile of the perception of control was obtained for Study 2. Conclusion: The high degree of perception of controlling drug use in the GP, and partially in drug users being treated, and the specific control strategies reported suggests that moderate use and drug control strategies are a great value alternative to bear in mind compared to abstinence.

Component Processes of Decision Making in a Community Sample of Precariously Housed Persons: Associations With Learning and Memory, and Health-Risk Behaviors

The Iowa Gambling Task (IGT) is a widely used measure of decision making, but its value in signifying behaviors associated with adverse, "real-world" consequences has not been consistently demonstrated in persons who are precariously housed or homeless. Studies evaluating the ecological validity of the IGT have primarily relied on traditional IGT scores. However, computational modeling derives underlying component processes of the IGT, which capture specific facets of decision making that may be more closely related to engagement in behaviors associated with negative consequences. This study employed the Prospect Valence Learning (PVL) model to decompose IGT performance into component processes in 294 precariously housed community residents with substance use disorders. Results revealed a predominant focus on gains and a lack of sensitivity to losses in these vulnerable community residents. Hypothesized associations were not detected between component processes and self-reported health-risk behaviors. These findings provide insight into the processes underlying decision making in a vulnerable substance-using population and highlight the challenge of linking specific decision making processes to "real-world" behaviors.

Reward-Related Responses and Tonic Craving in Cocaine Addiction: An Imaging Study of the Monetary Incentive Delay Task

BACKGROUND

Cocaine addiction is associated with altered sensitivity to natural reinforcers and intense drug craving. However, previous findings on reward-related responses were mixed, and few studies have examined whether reward responses relate to tonic cocaine craving.

METHODS

We combined functional magnetic resonance imaging and a monetary incentive delay task to investigate these issues. Imaging data were processed with published routines, and the results were evaluated with a corrected threshold. We compared reward responses of 50 cocaine-dependent individuals (CDs) and 45 healthy controls (HCs) for the ventral striatum (VS) and the whole brain. We also examined the regional responses in association with tonic cocaine craving, as assessed by the Cocaine Craving Questionnaire (CCQ) in CDs. We performed mediation analyses to evaluate the relationship between regional responses, CCQ score, and recent cocaine use.

RESULTS

The VS showed higher activation to large as compared with small or no wins, but this reward-related activity did not differ between CDs and HCs. The precentral gyrus (PCG), anterior insula, and supplementary motor area showed higher activation during large vs no wins in positive correlation with the CCQ score in CDs. Mediation analyses suggested that days of cocaine use in the prior month contributed to higher CCQ scores and, in turn, PCG reward responses.

CONCLUSIONS

The results highlight a unique relationship between reward responses of the primary motor cortex, tonic cocaine craving, and recent cocaine use. The motor cortex may partake in the cognitive motor processes critical to drug-seeking behavior in addicted individuals.

Blunted prefrontal signature of proactive inhibitory control in cocaine use disorder

BACKGROUND

Impulsivity is an established risk factor for substance use disorder (SUD). Integral to SUD recovery is proactive control (leveraging information about a potential need for behavioral restraint to marshal increased cognitive resources toward inhibition) when cues for drug use are unavoidable. However, proactive control is little studied in SUD, and is merely inferred from post-error performance adjustments.

METHODS

We probed covert neurocircuit signatures of proactive control in persons with SUD, as well as the moderating effects of incentives for successfully exerting proactive control. We administered a Monetary Incentive Stop Task (MIST) during functional magnetic resonance imaging of adults with cocaine use disorder (CUD; n = 21) and healthy controls (n = 21). The MIST blended the reward and loss-anticipatory cues of the Monetary Incentive Delay (MID) Task with a variant of the Stop-Signal Task, in which target color signaled whether or not withholding a response might be necessary.

RESULTS

In controls, but not in CUD participants, targets that signaled a potential need to stop (as a contrast with targets that signaled no need to stop) activated portions of right operculum akin to activation commonly elicited by stop signals, despite no actual stop signal. Across all participants, this proactive control activation did not relate to task behavior or to questionnaire impulsivity. Anticipatory incentive cues did not recruit ventral striatum.

CONCLUSIONS

These data suggest that persons with CUD show blunted covert signatures of attention and proactive control. This potentially accounts in part for the role of poor executive function in relapse vulnerability.

Motivational factors modulate left frontoparietal network during cognitive control in cocaine addiction

Cocaine addiction is characterized by alterations in motivational and cognitive processes involved in goal-directed behavior. Recent studies have shown that addictive behaviors can be attributed to alterations in the activity of large functional networks. The aim of this study was to investigate how cocaine addiction affected the left frontoparietal network during goal-directed behavior in a stop-signal task (SST) with reward contingencies by correct task performance. Twenty-eight healthy controls (HC) and 30 abstinent cocaine-dependent patients (ACD) performed SST with monetary reward contingencies while undergoing a functional magnetic resonance imaging scan. The results showed that the left frontoparietal network (FPN) displayed an effect of cocaine addiction depending on reward contingencies rather than inhibition accuracy; and, second, we observed a negative correlation between dependence severity and the modulation of the left FPN network by the monetary reward in ACD. These findings highlight the role of the left FPN in the motivational effects of cocaine dependence.

Identifying cognitive deficits in cocaine dependence using standard tests and machine learning

There is a growing need to address the variability in detecting cognitive deficits with standard tests in cocaine dependence (CD). The aim of the current study was to identify cognitive deficits by means of Machine Learning (ML) algorithms: Generalized Linear Model (Glm), Random forest (Rf) and Elastic Net (GlmNet), to allow more effective categorization of CD and Non-dependent controls (NDC and to address common methodological problems. For our validation, we used two independent datasets, the first consisted of 87 participants (53 CD and 34 NDC) and the second of 40 participants (20 CD and 20 NDC). All participants were evaluated with neuropsychological tests that included 40 variables assessing cognitive domains. Using results from the cognitive evaluation, the three ML algorithms were trained in the first dataset and tested on the second to classify participants into CD and NDC. While the three algorithms had a receiver operating curve (ROC) performance over 50%, the GlmNet was superior in both the training (ROC = 0.71) and testing datasets (ROC = 0.85) compared to Rf and Glm. Furthermore, GlmNet was capable of identifying the eight main predictors of group assignment (CD or NCD) from all the cognitive domains assessed. Specific variables from each cognitive test resulted in robust predictors for accurate classification of new cases, such as those from cognitive flexibility and inhibition domains. These findings provide evidence of the effectiveness of ML as an approach to highlight relevant sections of standard cognitive tests in CD, and for the identification of generalizable cognitive markers.

Kappa-opioid receptors, dynorphin, and cocaine addiction: a positron emission tomography study

Animal studies indicate that the kappa-opioid receptor/dynorphin system plays an important role in cocaine binges and stress-induced relapse. Our goal was to investigate changes in kappa-opioid receptor (KOR) availability in the human brain using positron emission tomography (PET), before and after a cocaine binge. We also investigated the correlation between KOR and stress-induced cocaine self-administration. PET imaging was performed with the KOR selective agonist [11C]GR103545. Subjects with cocaine-use disorder (CUD) underwent PET scans and performed two types of cocaine self-administration sessions in the laboratory as follows: (1) choice sessions following a cold pressor test, to induce stress, and (2) binge dosing of cocaine. This allowed us investigate the following: (1) the association between KOR binding and a laboratory model of stress-induced relapse and (2) the change in KOR binding following a 3-day cocaine binge, which is thought to represent a change in endogenous dynorphin. A group of matched healthy controls was included to investigate between group differences in KOR availability. A significant association between [11C]GR103545 binding and cocaine self-administration was seen: greater KOR availability was associated with more choices for cocaine. In addition, the 3-day cocaine binge significantly reduced [11C]GR103545 binding by 18% in the striatum and 14% across brain regions. No difference in [11C]GR103545 binding was found between the CUD subjects and matched controls. In the context of previous studies, these findings add to the growing evidence that pharmacotherapies targeting the KOR have the potential to significantly impact treatment development for cocaine-use disorder.

The long-term effects of cocaine use on cognitive functioning: A systematic critical review

BACKGROUND

The predominant view of chronic cocaine use maintains that it causes a broad range of cognitive deficits. However, concerns about the possibly deleterious impact of cocaine on cognitive functioning have yet to be thoroughly vetted. This review addresses the impact of cocaine use on such cognitive domains as executive function, memory, language, and psychomotor speed. Additionally, relevant neuroimaging data is considered to understand the neural basis underlying cocaine-related effects on cognitive functioning.

METHODS

We searched PubMed, Google Scholar, and Embase using the search terms "cocaine and cognition," "cocaine and cognitive functioning," and "cocaine and cognitive deficits or impairment." To meet inclusion criteria we evaluated only cognitive and neuroimaging studies describing the long-term effects of cocaine on cognitive functioning published from 1999 to 2016.

RESULTS

The majority of studies reported statistically significant differences between cocaine users and non-drug-using controls in brain structures, blood-oxygen-level dependent signals, and brain metabolism. However, differences in cognitive performance were observed on a minority of measures. Additionally, the majority of studies were not compared against normative data.

CONCLUSIONS

The current evidence does not support the view that chronic cocaine use is associated with broad cognitive deficits. The view that cocaine users have broad cognitive deficits is inaccurate based upon current evidence, and the perpetuation of this view may have negative implications for treatment programs and development of public policies.

Impulsive Action and Impulsive Choice Are Differentially Expressed in Rats Depending on the Age at Exposure to a Gambling Task

Impulsivity is considered an important feature associated with the development of numerous psychiatric disorders, including addictions. In the behavioral approach, impulsivity can be broadly divided into two distinct subtypes: impulsive action and choice. In the present study, we used a rodent version of the gambling task (rGT) to examine how impulsive action and impulsive choice are differentially influenced by difference in age at exposure (i.e., late adolescents/young adults vs. mature adults) to rGT. Rats were trained in a touch-screen chamber to learn the relationships between 4 light signals on the window of the screen and accompanying reward outcomes or punishments associated with different magnitudes and probabilities. Depending on their stabilized pattern of preference when allowed free choice, rats were categorized into risk-averse or risk-seeking group. While undergoing a series of experimental schemes, including extinction, re-acquisition, and acute cocaine injection, rats were re-tested for their premature response during inter-trial interval and choice preference toward the 4 different windows in rGT. Notably, rats exposed early, compared with those exposed late, to rGT showed increased impulsive action, particularly during re-acquisition period, in all sub-groups. In contrast, rats exposed late, compared with those exposed early, to rGT showed increased impulsive choice after acute cocaine injection, but these results were only obtained in a sub-group pre-categorized as high impulsive and risk-averse. These results suggest that different aspects of impulsivity can be differentially expressed during decision-making, and differentially influenced by the age at exposure to a gambling task.

Assessing cognitive functioning in individuals with cocaine use disorder

INTRODUCTION

There have been mixed findings assessing the impact of regular cocaine use on cognitive functioning. This study employed a comprehensive cognitive battery to compare the performance of individuals diagnosed with a cocaine use disorder (N = 3 abusers, N = 17 dependent) against the performance of two control groups: (a) non-drug-users, and (b) marijuana users who report no cocaine use (N = 7 marijuana abusers, N = 0 dependent, N = 13 marijuana users with no Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, DSM-IV, diagnosis).

METHOD

This one-session, between-participants, outpatient study was conducted at the New York State Psychiatric Institute. Sixty research volunteers completed the study. Drug users in both groups had no signs of current intoxication, but had a positive urine toxicology-which indicated use within 72 hours in the cocaine use disorder group and within the past 30 days (depending on frequency of use) for the marijuana-using control group. The National Institutes of Health (NIH) Toolbox Cognition Battery was used to assess cognitive functioning across six domains: executive function, attention, episodic memory, working memory, processing speed, and language. Each participant's score was also compared against a normative database adjusted for age.

RESULTS

Although the mean cognitive scores for all groups fell within the normal range for all tests, marijuana-using control participants outperformed those with a cocaine use disorder on a cognitive flexibility and language measure.

CONCLUSIONS

Cognitive functioning of individuals diagnosed with cocaine use disorder was observed to be similar to that of control group participants on the majority of tasks and fell within the normal range when compared against normative data.

Neuropsychological comparisons of cocaine versus methamphetamine users: A research synthesis and meta-analysis

BACKGROUND

Previous meta-analytical research examining cocaine and methamphetamine separately suggests potentially different neuropsychological profiles associated with each drug. In addition, neuroimaging studies point to distinct structural changes that might underlie differences in neuropsychological functioning.

OBJECTIVES

This meta-analysis compared the effect sizes identified in cocaine versus methamphetamine studies across 15 neuropsychological domains.

METHOD

Investigators searched and coded the literature examining the neuropsychological deficits associated with a history of either cocaine or methamphetamine use. A total of 54 cocaine and 41 methamphetamine studies were selected, yielding sample sizes of 1,718 and 1,297, respectively. Moderator analyses were conducted to compare the two drugs across each cognitive domain.

RESULTS

Data revealed significant differences between the two drugs. Specifically, studies of cocaine showed significantly larger effect-size estimates (i.e., poorer performance) in verbal working memory when compared to methamphetamine. Further, when compared to cocaine, methamphetamine studies demonstrated significantly larger effect sizes in delayed contextual verbal memory and delayed visual memory.

CONCLUSION

Overall, cocaine and methamphetamine users share similar neuropsychological profiles. However, cocaine appears to be more associated with working memory impairments, which are typically frontally mediated, while methamphetamine appears to be more associated with memory impairments that are linked with temporal and parietal lobe dysfunction.

Interaction between trait and housing condition produces differential decision-making toward risk choice in a rat gambling task

Poor decision-making is a core problem in psychiatric disorders such as pathological gambling and substance abuse. Both trait and environmental factors are considerably important to affect decision-making. However, it has not yet been systematically shown how they interact to affect risk preference in animal models evaluating decision-making. Here, we trained rats, housed in pairs or in isolation, in a touch screen chamber to detect the association between four different light signals on the screen and accompanied reward and punishment outcomes arranged with different schedules. Then, the rats were allowed to freely choose from 4 different light signals. Once animals showed a stabilized pattern of preference (risk-averse or risk-seeking), they were injected with saline or cocaine (a single injection per day for 7 days) followed by 2 weeks of withdrawal. Then, their preference of choice was re-tested in the touch screen chamber while they were cocaine challenged. All rats significantly changed their preference toward more risky choices when they were exposed to and challenged with cocaine, except those in the risk-averse/isolated housing group. These results indicate that the pre-existing trait toward risk and the housing condition interact to affect the quality of decision-making, and cocaine may help to aggravate this process.

Cocaine addiction is associated with abnormal prefrontal function, increased striatal connectivity and sensitivity to monetary incentives, and decreased connectivity outside the human reward circuit

Cocaine addiction has been associated with increased sensitivity of the human reward circuit to drug-related stimuli. However, the capacity of non-drug incentives to engage this network is poorly understood. Here, we characterized the functional sensitivity to monetary incentives and the structural integrity of the human reward circuit in abstinent cocaine-dependent (CD) patients and their matched controls. We assessed the BOLD response to monetary gains and losses in 30 CD patients and 30 healthy controls performing a lottery task in a magnetic resonance imaging scanner. We measured brain gray matter volume (GMV) using voxel-based morphometry and white matter microstructure using voxel-based fractional anisotropy (FA). Functional data showed that, after monetary incentives, CD patients exhibited higher activation in the ventral striatum than controls. Furthermore, we observed an inverted BOLD response pattern in the prefrontal cortex, with activity being highest after unexpected high gains and lowest after losses. Patients showed increased GMV in the caudate and the orbitofrontal cortex, increased white matter FA in the orbito-striatal pathway but decreased FA in antero-posterior association bundles. Abnormal activation in the prefrontal cortex correlated with GMV and FA increases in the orbitofrontal cortex. While functional abnormalities in the ventral striatum were inversely correlated with abstinence duration, structural alterations were not. In conclusion, results suggest abnormal incentive processing in CD patients with high salience for rewards and punishments in subcortical structures but diminished prefrontal control after adverse outcomes. They further suggest that hypertrophy and hyper-connectivity within the reward circuit, to the expense of connectivity outside this network, characterize cocaine addiction.

Reward Contingencies Improve Goal-Directed Behavior by Enhancing Posterior Brain Attentional Regions and Increasing Corticostriatal Connectivity in Cocaine Addicts

The dopaminergic system provides the basis for the interaction between motivation and cognition. It is triggered by the possibility of obtaining rewards to initiate the neurobehavioral adaptations necessary to achieve them by directing the information from motivational circuits to cognitive and action circuits. In drug addiction, the altered dopamine (DA) modulation of the meso-cortico-limbic reward circuitry, such as the prefrontal cortex (PFC), underlies the disproportionate motivational value of drug use at the expense of other non-drug reinforcers and the user's loss of control over his/her drug intake. We examine how the magnitude of the reward affects goal-directed processes in healthy control (HC) subjects and abstinent cocaine dependent (ACD) patients by using functional magnetic resonance imaging (fMRI) during a counting Stroop task with blocked levels of monetary incentives of different magnitudes (€0, €0.01, €0.5, €1 or €1.5). Our results showed that increasing reward magnitude enhances (1) performance facilitation in both groups; (2) left dorsolateral prefrontal cortex (DLPFC) activity in HC and left superior occipital cortex activity in ACD; and (3) left DLPFC and left putamen connectivity in ACD compared to HC. Moreover, we observed that (4) dorsal striatal and pallidum activity was associated with craving and addiction severity during the parametric increases in the monetary reward. In conclusion, the brain response to gradients in monetary value was different in HC and ACD, but both groups showed improved task performance due to the possibility of obtaining greater monetary rewards.

Risky Decisions in a Lottery Task Are Associated with an Increase of Cocaine Use

Cocaine use disorder is associated with maladaptive decision-making behavior, which strongly contributes to the harmful consequences of chronic drug use. Prior research has shown that cocaine users exhibit impaired neuropsychological test performances, particularly with regard to attention, learning, and memory but also in executive functions such as decision-making and impulse control. However, to what extent cocaine users show impaired decision-making under risk without feedback has not yet been investigated systematically. Therefore, to examine risk-taking behavior, 31 chronic cocaine users and 26 stimulant-naïve healthy controls who were part of the Zurich Cocaine Cognition Study, performed the Randomized Lottery Task (RALT) with winning lotteries consisting of an uncertain and a certain prospect. Results revealed that risky decisions were associated with male sex, increased cocaine use in the past year, higher cocaine concentrations in the hair, and younger age. In addition, higher levels of cocaine in the hair and cumulative lifetime consumption were associated with risky decisions, whereas potentially confounding factors including cognition and psychiatric symptoms had no significant effect. Taken together, our results indicate that cocaine users who increased their consumption over a period of 1 year show deficits in the processing of risky information accompanied with increased risk-taking. Future research should analyse whether risky decisions could potentially serve as a prognostic marker for cocaine use disorder.

Comments and controversies: Piecing together the neurobiology of decision-making

In this paper, we address issues raised by Tierney and Hart (Assessing Complex Cognitive Functioning Requires Multiple Tasks) in response to our recently published findings showing that less advantageous decision-making on the Iowa Gambling Task (IGT) was associated with enhanced right ventral striatal dopamine response to intravenous amphetamine (Oswald et al., 2015). We agree with the overall premise of the paper, which was that decision-making involves multiple components, which may not be tapped by a single measure. While Tierney and Hart also bring up some important issues related to the construct validity of the IGT, we suggest that they are failing to put the findings within the context of the growing body of research that has highlighted the role of DA function in risk-taking behavior across species using a variety of tasks. It should also be noted that it was not our goal to "cover all bases" within the context of a single study. Nevertheless, we appreciate the discussion, which we believe highlights the need for further empirical refinement of the construct to facilitate detection and understanding of the differential role that specific molecular mechanisms may play in the component processes.

Cocaine Self-Administration Experience Induces Pathological Phasic Accumbens Dopamine Signals and Abnormal Incentive Behaviors in Drug-Abstinent Rats

Chronic exposure to drugs of abuse is linked to long-lasting alterations in the function of limbic system structures, including the nucleus accumbens (NAc). Although cocaine acts via dopaminergic mechanisms within the NAc, less is known about whether phasic dopamine (DA) signaling in the NAc is altered in animals with cocaine self-administration experience or if these animals learn and interact normally with stimuli in their environment. Here, separate groups of rats self-administered either intravenous cocaine or water to a receptacle (controls), followed by 30 d of enforced abstinence. Next, all rats learned an appetitive Pavlovian discrimination and voltammetric recordings of real-time DA release were taken in either the NAc core or shell of cocaine and control subjects. Cocaine experience differentially impaired DA signaling in the core and shell relative to controls. Although phasic DA signals in the shell were essentially abolished for all stimuli, in the core, DA did not distinguish between cues and was abnormally biased toward reward delivery. Further, cocaine rats were unable to learn higher-order associations and even altered simple conditioned approach behaviors, displaying enhanced preoccupation with cue-associated stimuli (sign-tracking; ST) but diminished time at the food cup awaiting reward delivery (goal-tracking). Critically, whereas control DA signaling correlated with ST behaviors, cocaine experience abolished this relationship. These findings show that cocaine has persistent, differential, and pathological effects on both DA signaling and DA-dependent behaviors and suggest that psychostimulant experience may remodel the very circuits that bias organisms toward repeated relapse.

SIGNIFICANCE STATEMENT

Relapsing to drug abuse despite periods of abstinence and sincere attempts to quit is one of the most pernicious facets of addiction. Unfortunately, little is known about how the dopamine (DA) system functions after periods of drug abstinence, particularly its role in behavior in nondrug situations. Here, rats learned about food-paired stimuli after prolonged abstinence from cocaine self-administration. Using voltammetry, we found that real-time DA signals in cocaine-experienced rats were strikingly altered relative to controls. Further, cocaine-experienced animals found reward-predictive stimuli abnormally salient and spent more time interacting with cues. Therefore, cocaine induces neuroplastic changes in the DA system that biases animals toward salient stimuli (including reward-associated cues), putting addicts at increasing risk to relapse as addiction increases in severity.

Changes in cocaine consumption are associated with fluctuations in self-reported impulsivity and gambling decision-making

BACKGROUND

In cross-sectional studies, cocaine users generally display elevated levels of self-reported and cognitive impulsivity. To what extent these impairments are stable v. variable markers of cocaine use disorder, and, thus, are pre-existing or drug-induced, has not yet been systematically investigated.

METHOD

We conducted a longitudinal study with cocaine users who changed or maintained their consumption intensity, measuring self-reported impulsivity with the Barratt Impulsiveness Scale (BIS-11), and cognitive impulsivity with the Rapid Visual Processing task (RVP), Iowa Gambling task (IGT), and Delay Discounting task (DD) at baseline and at 1-year follow-up. We assessed 48 psychostimulant-naive controls and 19 cocaine users with decreased, 19 users with increased, and 19 users with unchanged cocaine intake after 1 year as confirmed by hair analysis.

RESULTS

Results of linear multilevel modelling showed significant group × time interactions for the BIS-11 total score and the IGT total card ratio. Increasers showed a trend for elevated scores, whereas decreasers exhibited reduced self-reported impulsivity scores within 1 year. Surprisingly, increasers' IGT performance was improved after 1 year, whereas decreasers' performance deteriorated. By contrast, neither RVP response bias B" nor DD total score showed substantial group × time interactions. Importantly, BIS-11 and DD revealed strong test-retest reliabilities.

CONCLUSION

Self-reported impulsivity (BIS-11) and decision-making impulsivity (IGT) covary with changing cocaine use, whereas response bias and delay discounting remain largely unaffected. Thus, self-reported impulsivity and gambling decision-making were strongly state-dependent in a stimulant-using population and may be suitable to monitor treatment success, whereas delay of gratification was confirmed as a potential endophenotype of stimulant addiction.

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.

Understanding and shifting drug-related decisions: contributions of automatic decision-making processes

While substance use is common, only a minority of individuals who use drugs or alcohol develop problematic use. An understanding of the factors underlying the transition from substance use to misuse may improve prevention and intervention efforts. A key feature of substance misuse is ongoing decisions to use drugs or alcohol despite escalating negative consequences. Research findings highlight the importance of both relatively automatic, associative cognitive processes and relatively controlled, deliberative, and rational-analytic cognitive processes, for understanding situational decisions to use drugs. In this review, we discuss several cognitive component processes that may contribute to decision-making that promotes substance use and misuse, with a focus on more automatic processes. A growing body of evidence indicates that relative differences in the strength of these component processes can account for individual differences in the transition from substance use to misuse and may offer important avenues for developing novel intervention strategies.

Decision making in healthy participants on the Iowa Gambling Task: new insights from an operant approach

The Iowa Gambling Task (IGT) has contributed greatly to the study of affective decision making. However, researchers have observed high inter-study and inter-individual variability in IGT performance in healthy participants, and many are classified as impaired using standard criteria. Additionally, while decision-making deficits are often attributed to atypical sensitivity to reward and/or punishment, the IGT lacks an integrated sensitivity measure. Adopting an operant perspective, two experiments were conducted to explore these issues. In Experiment 1, 50 healthy participants completed a 200-trial version of the IGT which otherwise closely emulated Bechara et al.'s (1999) original computer task. Group data for Trials 1–100 closely replicated Bechara et al.'s original findings of high net scores and preferences for advantageous decks, suggesting that implementations that depart significantly from Bechara's standard IGT contribute to inter-study variability. During Trials 101–200, mean net scores improved significantly and the percentage of participants meeting the “impaired” criterion was halved. An operant-style stability criterion applied to individual data revealed this was likely related to individual differences in learning rate. Experiment 2 used a novel operant card task—the Auckland Card Task (ACT)—to derive quantitative estimates of sensitivity using the generalized matching law. Relative to individuals who mastered the IGT, persistent poor performers on the IGT exhibited significantly lower sensitivity to magnitudes (but not frequencies) of rewards and punishers on the ACT. Overall, our findings demonstrate the utility of operant-style analysis of IGT data and the potential of applying operant concurrent-schedule procedures to the study of human decision making.

Steeper delay and probability discounting of potentially real versus hypothetical cigarettes (but not money) among smokers

There is a strong relationship between drug use and the tendency to discount the value of outcomes as a function of their delay and probability. Most discounting researchers use hypothetical monetary outcomes to establish discounting patterns among human subjects, who tend to discount the value of hypothetical money and real money similarily. However, no research to date has examined whether hypothetical non-monetary outcomes are discounted similarly to real non-monetary outcomes. In this study, smokers were assigned randomly to complete delay and probability discounting tasks for money and cigarettes that were either potentially real (n=33) or hypothetical (n=31). Consistent with previous research, smokers discounted the value of hypothetical and potentially real money similarly. However, smokers evidenced steeper rates of discounting for potentially real cigarettes in both delay and probability discounting. These findings suggest domain-specific discounting patterns in which potentially real and hypothetical outcomes may be synonymous in the context of monetary outcomes, but not in the context of non-monetary outcomes.

Altered social and non-social decision-making in recreational and dependent cocaine users

BACKGROUND

Maladaptive decision-making is assumed to be a core feature of cocaine addiction. Indeed, numerous studies have reported deficits in non-social decision-making tasks and reward-related impulsivity in dependent cocaine users. However, social decision-making has not been examined in cocaine users yet. Moreover, it is unknown if even recreational and non-dependent cocaine use is linked to decision-making deficits. Therefore, we investigated whether recreational and dependent cocaine users exhibit alterations in social and non-social decision-making.

METHOD

The performance of healthy controls (n = 68), recreational cocaine users (n = 68) and dependent cocaine users (n = 30) in classical decision-making paradigms (Iowa Gambling Task, Delay Discounting) and in social interaction paradigms (Distribution Game, Dictator Game) was assessed.

RESULTS

Decisions in the social interaction tasks of both cocaine user groups were more self-serving compared with controls as cocaine users preferred higher monetary payoffs for themselves. In the Iowa Gambling Task, only dependent cocaine users were more likely to choose disadvantageous card decks, reflecting worse decision-making. They were also more likely to choose immediate smaller rewards over larger delayed rewards in the Delay Discounting task.

CONCLUSIONS

Our results imply that both recreational and dependent cocaine users are more concerned with their own monetary gain when interacting with another person. Furthermore, primarily dependent cocaine users are less foresighted and more impulsive regarding immediate reward. Overall, social interaction deficits are already present in recreational users, while non-social decision-making deficits occur predominantly in dependent cocaine users. Thus, social interaction training and cognitive remediation strategies may improve treatment success and quality of life in cocaine dependence.

Addiction and the brain-disease fallacy

From Brainwashed: The Seductive Appeal of Mindless Neuroscience by Sally Satel and Scott Lilienfeld, copyright © 2013. Reprinted by permission of Basic Books, a member of The Perseus Books Group. The notion that addiction is a "brain disease" has become widespread and rarely challenged. The brain-disease model implies erroneously that the brain is necessarily the most important and useful level of analysis for understanding and treating addiction. This paper will explain the limits of over-medicalizing - while acknowledging a legitimate place for medication in the therapeutic repertoire - and why a broader perspective on the problems of the addicted person is essential to understanding addiction and to providing optimal care. In short, the brain-disease model obscures the dimension of choice in addiction, the capacity to respond to incentives, and also the essential fact people use drugs for reasons (as consistent with a self-medication hypothesis). The latter becomes obvious when patients become abstinent yet still struggle to assume rewarding lives in the realm of work and relationships. Thankfully, addicts can choose to recover and are not helpless victims of their own "hijacked brains."

Characterizing the cognitive effects of cocaine: a comprehensive review

Understanding the cognitive sequela of repeated cocaine use is a growing area of research and is crucial to the development of cognitive models of addiction. We systematically reviewed all available placebo-controlled and case-controlled studies on the acute and long-term effects of cocaine on cognitive functioning. In order to compare the magnitude of cognitive effects across cognitive domains we conducted several meta-analyses on a subset of data from long-term effect studies. Studies on acute cocaine administration suggest enhancement of response inhibition and psychomotor speed, while all other domains appear to be unaffected or not investigated adequately. Long-term effects of cocaine show a wide array of deteriorated cognitive functions, indicating that long term cocaine use is characterized by a general cognitive impairment across functions, rather than by specific cognitive deficits. Literature on long-term cocaine effects is more substantial than literature on acute effects. This comprehensive review outlines possible dissociations and similarities of acute vs. long-term cocaine effects in the human brain. Atherosclerosis after cocaine exposure may underlie cognitive dysfunction, suggesting involvement of multiple brain areas. Acute drug studies are important to the future development of addiction models.

O Iowa Gambling Task: uma revisão crítica

O Iowa Gambling Task (IGT) é uma tarefa amplamente utilizada na avaliação da capacidade de tomada de decisão. Neste artigo, procede-se à revisão da literatura, comparando-se as versões do IGT, as diferentes medidas de avaliação do desempenho e as alterações introduzidas nos procedimentos, nomeadamente no feedback, na aleatorização espacial dos baralhos, no número de ensaios e de cartas por baralho, nas instruções, na remuneração e na manipulação das recompensas e punições. Desta análise, conclui-se que as diversas versões da tarefa, as alterações nos procedimentos de aplicação e as diferentes medidas utilizadas na avaliação têm impacto no desempenho, prejudicam a comparação entre estudos e as generalizações dos resultados. Finalmente, apresentam-se sugestões para uma maior adequação dos procedimentos.

Choice to view cocaine images predicts concurrent and prospective drug use in cocaine addiction

BACKGROUND

Identifying variables that predict drug use in treatment-seeking drug addicted individuals is a crucial research and therapeutic goal. This study tested the hypothesis that choice to view cocaine images is associated with concurrent and prospective drug use in cocaine addiction.

METHODS

To establish choice-concurrent drug use associations, 71 cocaine addicted subjects (43 current users and 28 treatment seekers) provided data on (A) choice to view cocaine images and affectively pleasant, unpleasant, and neutral images [collected under explicit contingencies (when choice was made between two fully visible side-by-side images) and under more probabilistic contingencies (when choice was made between pictures hidden under flipped-over cards)]; and (B) past-month cocaine and other drug use. To establish choice-prospective drug use associations, 20 of these treatment-seeking subjects were followed over the next 6 months.

RESULTS

Baseline cocaine-related picture choice as measured by both tasks positively correlated with subjects' concurrent cocaine and other drug use as driven by the actively-using subjects. In a subsequent multiple regression analysis, choice to view cocaine images as compared with affectively pleasant images (under probabilistic contingencies) was the only predictor that continued to be significantly associated with drug use. Importantly, this same baseline cocaine>pleasant probabilistic choice also predicted the number of days drugs were used (cocaine, alcohol, and marijuana) over the next 6 months.

CONCLUSIONS

Simulated cocaine choice - especially when probabilistic and when compared with other positive reinforcers - may provide a valid laboratory marker of current and future drug use in cocaine addiction.

Illicit drug use and problem gambling

Problem gambling, substance use disorders, and their cooccurrence are serious public health concerns. We conducted a comprehensive review of the literature to understand the present state of the evidence on these coaddictions. Our main focus was illicit drug use rather than misuse of legal substances. The review covers issues related to gambling as a hidden problem in the illicit drug use community; prevalence, problem gambling, and substance use disorders as kindred afflictions; problem gambling as an addiction similar to illicit drug use; risk factors and problems associated with comorbidity, and gender issues. We end with some suggestions for future research.

Performance of young adult cannabis users on neurocognitive measures of impulsive behavior and their relationship to symptoms of cannabis use disorders

Recent studies suggest that abstinent cannabis users show deficits on neurocognitive laboratory tasks of impulsive behavior. But results are mixed, and less is known on the performance of non-treatment-seeking, young adult cannabis users. Importantly, relationships between performance on measures of impulsive behavior and symptoms of cannabis addiction remain relatively unexplored. We compared young adult current cannabis users (CU, n = 65) and nonusing controls (NU, n = 65) on several laboratory measures of impulsive behavior, as well as on a measure of episodic memory commonly impacted by cannabis use. The CU group performed more poorly than the NU group on the Hopkins Verbal Learning Test-Revised Total Immediate Recall and Delayed Recall. No significant differences were observed on the measures of impulsive behavior (i.e., Iowa Gambling Task, IGT; Go-Stop Task; Monetary Choice Questionnaire; Balloon Analogue Risk Task). We examined relationships between neurocognitive performance and symptoms of cannabis use disorder symptoms (Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, DSM-IV CUD) among the CU group, which revealed that poorer IGT performance was associated with more symptoms of DSM-IV CUD. Our results show poorer memory performance among young adult cannabis users than among healthy controls, but no differences on measures of impulsive behavior. However, performance on a specific type of impulsive behavior (i.e., poorer decision making) was associated with more cannabis use disorder symptoms. These results provide preliminary evidence to suggest that decision-making deficits may be more strongly associated with problems experienced from cannabis use, rather than solely being a consequence of cannabis use, per se.

Tomada de decisão em dependentes de crack: um estudo com o Iowa Gambling Task

Este estudo investigou como ocorre o processo de tomada de decisão em dependentes de crack pelo instrumento Iowa Gambling Task (IGT). Foram selecionados 30 participantes para o grupo de dependentes de crack - GDC, e 15 controles não usuários - GNU, de ambos os sexos. Para avaliar a intensidade de craving utilizou-se o Cocaine Craving Questionnaire-Brief. Houve diferenças significativas entre os grupos tanto no cálculo total, como no cálculo por blocos. A curva de aprendizagem do GDCmanteve-se constante e negativa na maior parte do jogo, havendo apenas no final um indício de aprendizagem. Em relação à classificação do desempenho na tarefa, as análises evidenciaram que um significativo número de participantes controles obtiveram desempenho não-prejudicado, oposto ao desempenho do GDC. As diferenças entre os grupos investigadas no IGT corroboraram com achado de estudo anterior, que evidenciou prejuízo no processo de tomada de decisão associado à dependência de cocaína e de crack.

Effects of chronic marijuana use on brain activity during monetary decision-making

Marijuana (MJ) acutely acts on cannabinoid receptors that are found in numerous brain regions, including those involved in reward processing and decision-making. However, it remains unclear how long-term, chronic MJ use alters reward-based decision-making. In the present study, using [(15)O]water PET imaging, we measured brain activity in chronic MJ users, who underwent monitored abstinence from MJ for approximately 24 h before imaging, and control participants, while they took part in the Iowa Gambling Task (IGT), a monetary decision making task that strongly relies on the ventromedial prefrontal cortex (vmPFC). During PET imaging, participants took part in the standard and a variant version of the IGT as well as a control task. Chronic MJ users performed equally well on the standard IGT, but significantly worse than controls on the variant IGT. Chronic MJ users and control subjects showed increased regional cerebral blood flow (rCBF) in the vmPFC on both versions of the IGT compared to the control task. In the two-group comparison, chronic MJ users showed significantly greater rCBF than controls in the vmPFC on the standard IGT and greater activity in the cerebellum on both versions of the IGT. Furthermore, duration of use, but not age of first use, was associated with greater activity in the vmPFC. Thus, chronic MJ users tend to strongly recruit neural circuitry involved in decision-making and reward processing (vmPFC), and probabilistic learning (cerebellum) when performing the IGT.

Differences in self-reported decision-making styles in stimulant-dependent and opiate-dependent individuals

In light of the growing evidence of altered decision-making in addiction we assessed decision-making styles in drug-dependent individuals using the Melbourne Decision-Making Questionnaire (MDMQ). Consistent with the literature on laboratory tests of decision-making, we found that stimulant users reported less competent and more maladaptive decision-making styles compared with controls.

Psychopathic heroin addicts are not uniformly impaired across neurocognitive domains of impulsivity

BACKGROUND

Impulsivity is a hallmark characteristic of drug addiction and a prominent feature of externalizing disorders such as psychopathy that are commonly comorbid with drug addiction. In a previous study (Vassileva et al., 2007) we have shown that psychopathic heroin addicts evidence more impulsive decision-making on the Iowa Gambling Task relative to non-psychopathic heroin addicts. The goal of the current study was to investigate whether the observed impulse-control deficits in psychopathic heroin addicts would generalize to other neurocognitive domains of impulsivity, such as delay discounting and behavioral inhibition among a group of relatively "pure" heroin addicts in Bulgaria who participated in our previous study.

METHODS

We tested 92 currently abstinent male heroin addicts, classified as psychopathic or non-psychopathic based on the Hare Psychopathy Checklist - Revised (PCL-R). We administered two neurocognitive tasks of impulsivity: (1) Delayed Rewards Discounting Task, a measure of temporal discounting of rewards; and (2) Passive Avoidance Learning Task, a measure of behavioral inhibition.

RESULTS

Psychopathic heroin addicts were not impaired relative to non-psychopathic heroin addicts on the Delayed Rewards Discounting Task and the Passive Avoidance Learning Task, on the latter of which they showed better attentional capacity.

CONCLUSIONS

These results indicate that psychopathic heroin users are not uniformly impaired across neurocognitive domains of impulsivity. Combined with our previous findings, results suggest that the presence of psychopathy may exacerbate decision-making deficits in psychopathic heroin addicts, but it may not have significant effect on other neurocognitive domains of impulsivity in this population.

Poor decision-making by chronic marijuana users is associated with decreased functional responsiveness to negative consequences

Chronic marijuana users (MJ Users) perform poorly on the Iowa Gambling Task (IGT), a complex decision-making task in which monetary wins and losses guide strategy development. This functional magnetic resonance imaging (MRI) study sought to determine if the poor performance of MJ Users was related to differences in brain activity while evaluating wins and losses during the strategy development phase of the IGT. MJ Users (16) and Controls (16) performed a modified IGT in an MRI scanner. Performance was tracked and functional activity in response to early wins and losses was examined. While the MJ Users continued to perform poorly at the end of the task, there was no difference in group performance during the initial strategy development phase. During this phase, before the emergence of behavioral differences, Controls exhibited significantly greater activity in response to losses in the anterior cingulate cortex, medial frontal cortex, precuneus, superior parietal lobe, occipital lobe and cerebellum as compared to MJ Users. Furthermore, in Controls, but not MJ Users, the functional response to losses in the anterior cingulate cortex, ventral medial prefrontal cortex and rostral prefrontal cortex positively correlated with performance over time. These data suggest MJ Users are less sensitive to negative feedback during strategy development.

Cocaine abuse versus cocaine dependence: cocaine self-administration and pharmacodynamic response in the human laboratory

Cocaine has high abuse liability but only a subset of individuals who experiment with it develop dependence. The DSM-IV (APA. Diagnostic and Statistical Manual of Mental Disorders DSM-IV-R. American Psychiatric Association, Washington, DC, 2000) provides criteria for diagnosing cocaine abuse and cocaine dependence as distinct disorders- the latter characterized by additional symptoms related to loss of control over drug use. In this study, two groups of cocaine users (n=8/group), matched on demographic factors and length of cocaine use history and meeting criteria for either cocaine abuse (CocAb) or cocaine dependence (CocDep), were compared on (1) measures related to impulsivity and sensation seeking, (2) response to experimenter-administered cocaine (0, 12.5, 25 and 50mg/70 kg, i.v.), and (3) cocaine self-administration using a Relapse Choice and a Progressive Ratio Procedure (0, 12.5 and 25mg/70 kg, i.v.). Groups did not differ on impulsivity or sensation seeking scores. After experimenter-administered cocaine, the CocAb group reported feeling more suspicious and observers rated them significantly higher on unpleasant effects (e.g., irritability, difficulty concentrating). In contrast, the CocDep group reported significantly greater desire for cocaine, which was sustained over the course of the study, and gave higher street value estimates for cocaine (p<0.05). While cocaine self-administration was dose-related and generally comparable across the two procedures, the CocDep users chose to take significantly more cocaine than the CocAb users. These data suggest that, while regular long-term users of cocaine with cocaine abuse or dependence diagnoses cannot be distinguished by trait measures related to impulsivity, they do exhibit significant differences with regard to cocaine-directed behavior and response to cocaine administration.

Failure to find executive function deficits following one night's total sleep deprivation in university students under naturalistic conditions

Young adult male students participated in a naturalistic, group-design experiment to ascertain the effects of one night's total sleep deprivation (TSD) on performance of diverse executive function tasks presented as an extended, multitask battery. On the majority of component tasks in this battery, performance has been reported to be impaired following one night's TSD when tasks are administered in isolation. However, participants sleep deprived 35 to 39 hr showed few performance deficits among tests in this battery when compared with non-sleep-deprived controls. Sleep-deprived participants showed only poorer recognition memory and overconfidence in incorrect temporal judgments. Behavioral and physiological adaptation to chronically sleep-restricting lifestyles may confer resistance to the cognitive effects of sleep deprivation in high-functioning young adults.