Óscar M. Lozano

Comparison of impulsivity and working memory in cocaine addiction and pathological gambling : implications for cocaine-induced neurotoxicity

BACKGROUND The aim of this study was to compare the cognitive performance of cocaine dependent individuals (CDI) with that of pathological gamblers (PG). Cocaine dependence and pathological gambling share neurobiological vulnerabilities related to addiction, but PG are relatively free of the toxic consequences, such that any additional deficits observed in CDI may be interpreted as pertaining to specific drug effects. METHODS We used a case-control observational design contrasting multiple measures of impulsivity (UPPS-P trait impulsivity, delay discounting) and executive measures of response inhibition (Stroop) and working memory performance (N-back) between groups of CDI (n=29), PG (n=23), and healthy controls (n=20). We conducted one-way ANOVAs, followed by planned pairwise tests and calculations of Cohens d to estimate significant differences between the groups. RESULTS CDI, as compared to PG, had elevated scores on UPPS-P Negative Urgency and poorer performance on working memory (2-back). PG had steeper delay-discounting rates. Both groups had elevated Positive Urgency and poorer Stroop inhibition compared to controls. Peak amount of cocaine use was negatively correlated with working memory and response inhibition performance. CONCLUSION We found cocaine-related specific elevations in Negative Urgency and working memory deficits, putatively identified as cocaine neurotoxicity effects. Other aspects of impulsivity (Positive Urgency, Stroop inhibition) were increased across CDI and PG groups and may reflect vulnerability factors for addiction.

Psychometric Properties of a Spanish Version of the UPPS–P Impulsive Behavior Scale: Reliability, Validity and Association With Trait and Cognitive Impulsivity

Impulsivity is a multifaceted construct central to several forms of psychopathology. Recently, Lynam, Smith, Whiteside, and Cyders (2006) developed the UPPS–P scale, a multidimensional inventory that assesses 5 personality pathways contributing to impulsive behavior: negative urgency, lack of perseverance, lack of premeditation, sensation seeking, and positive urgency. In this study, we aimed (a) to analyze the psychometric properties of a Spanish version of the UPPS–P scale and (b) to explore the relationship between the different dimensions of the UPPS–P scale and conceptually related constructs including trait measures derived from different models of impulsive personality (the Grays [1987] and Plutchiks [1984] models) and a state measure of cognitive impulsivity, the Delay-Discounting Test (Kirby, Petry, & Bickel, 1999). We administered the UPPS–P scale along with the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (Torrubia, Avila, Molto, & Caseras, 2001), the Plutchik Impulsivity Scale (Plutchik & Van Praag, 1989), and the Delay-Discounting Test to a sample of 150 undergraduate students. Results showed that the Spanish adaptation of the UPPS–P scale have appropriate psychometric properties. Different dimensions of the UPPS–P were differentially associated with predicted conceptually related constructs. We conclude that the Spanish adaptation of the UPPS–P scale is a useful instrument for fine-grained assessment of impulsivity in Spanish-speaking adult population.

Impulsivity and executive functions in polysubstance-using rave attenders

ObjectivesRave parties are characterized by high levels of drug use and polysubstance-using patterns that may be especially harmful for psychological and neuropsychological functioning. The aim of this study was to conduct a comprehensive assessment of different aspects of impulsivity and executive functions in a sample of polysubstance-using rave attenders.MethodsWe collected data from two groups: rave attenders (RvA, n = 25) and drug-free healthy comparison individuals (HCI, n = 27). RvA were regular users of cannabis, cocaine, methampethamine, hallucinogens, and alcohol. The assessment protocol included a drug-taking interview, the UPPS-P Impulsive Behavior Scale, the delay-discounting questionnaire and a set of neuropsychological tests taxing different aspects of executive functions: response speed, working memory, reasoning, response inhibition and switching, self-regulation, decision making, and emotion perception.ResultsFor impulsivity measures, RvA had significantly elevated scores on lack of perseverance and positive and negative urgency, but did not differ from controls on lack of premeditation or sensation seeking. For neuropsychological functioning, RvA had significantly poorer performance on indices of analogical reasoning, processing speed, working memory, inhibition/switching errors, and decision making, but performed similar to controls on indices of self-regulation, reversal learning, and emotion processing. Peak and binge alcohol and drug use were positively correlated with positive urgency, and negatively correlated with performance on executive indices.ConclusionRave attenders have selective alterations of impulsive personality and executive functions. These findings can contribute to delineate the neuropsychological profiles that distinguish recreational polysubstance use from substance dependence.

Bright and dark sides of impulsivity: Performance of women with high and low trait impulsivity on neuropsychological tasks

We administered a multidimensional measure of trait impulsivity (the UPPS-P impulsivity scale; Cyders et al., 2007) to a nonclinical sample of 155 individuals and selected 32 participants at the two ends of the trait impulsivity continuum: high (HI, n = 15) and low (LI, n = 17) impulsive women. We further tested these extreme groups on neuropsychological measures of motor impulsivity (go/no-go, d2), delay discounting (Now or Later Questionnaire), reflection impulsivity (Matching Familiar Figures Test), self-regulation (Revised-Strategy Application Test), and decision making (Iowa Gambling Task). High-trait-impulsivity women were found to commit more commission errors in the initial stage of the go/no-go task but also to make fewer omission errors in the d2 test than did low-trait-impulsivity women. Both effects can be accounted for by a lower response criterion in impulsive women. On the other hand, measures of delay discounting, reflection impulsivity, self-regulation, and decision making did not yield significant differences between the two groups. This pattern of results supports the idea that trait impulsivity in healthy women is linked to neurocognitive mechanisms involved in response monitoring and inhibition, but not to mechanisms involved in self-regulation or decision making. These findings temper the assumption that impulsivity is the core cause of dysfunctional risky and/or impulsive behavior in psychopathological or neuropsychological profiles.

Impact of severity of drug use on discrete emotions recognition in polysubstance abusers

Neuropsychological studies support the association between severity of drug intake and alterations in specific cognitive domains and neural systems, but there is disproportionately less research on the neuropsychology of emotional alterations associated with addiction. One of the key aspects of adaptive emotional functioning potentially relevant to addiction progression and treatment is the ability to recognize basic emotions in the faces of others. Therefore, the aims of this study were: (i) to examine facial emotion recognition in abstinent polysubstance abusers, and (ii) to explore the association between patterns of quantity and duration of use of several drugs co-abused (including alcohol, cannabis, cocaine, heroin and MDMA) and the ability to identify discrete facial emotional expressions portraying basic emotions. We compared accuracy of emotion recognition of facial expressions portraying six basic emotions (measured with the Ekman Faces Test) between polysubstance abusers (PSA, n=65) and non-drug using comparison individuals (NDCI, n=30), and used regression models to explore the association between quantity and duration of use of the different drugs co-abused and indices of recognition of each of the six emotions, while controlling for relevant socio-demographic and affect-related confounders. Results showed: (i) that PSA had significantly poorer recognition than NDCI for facial expressions of anger, disgust, fear and sadness; (ii) that measures of quantity and duration of drugs used significantly predicted poorer discrete emotions recognition: quantity of cocaine use predicted poorer anger recognition, and duration of cocaine use predicted both poorer anger and fear recognition. Severity of cocaine use also significantly predicted overall recognition accuracy.

Psychiatric comorbidity in cocaine users treated in therapeutic community: Substance-induced versus independent disorders

This is a cross-sectional study of 227 cocaine dependent individuals in six different therapeutic communities (TCs) within a single treatment network in Andalusia (Spain). The primary aim of the study is to examine the prevalence of lifetime psychiatric comorbidity in this sample using the Psychiatric Research Interview for Substance and Mental Disorders (PRISM). Diagnoses were assessed 15-20 days after admission. The data indicate that more than 65% of the sample experienced a lifetime co-occurring psychiatric comorbidity. Substance-induced mood (21.6%) and psychotic (11.5%) disorders were more prevalent in this population than independent mood (12.3%) and psychotic (7.5%) disorders. These data suggest the need to introduce changes in these centers, both in the diagnostic aspects and in the treatment programs.

Self-regulation and treatment retention in cocaine dependent individuals: A longitudinal study

BACKGROUND We aimed to explore the association between baseline executive functioning and treatment outcome in Therapeutic Communities (TCs). METHODS We used a longitudinal descriptive design: a baseline neuropsychological assessment was performed within the first 30 days of treatment in TCs. Once participants finished or abandoned treatment, the information about time of stay in treatment was computed for each individual. The study was conducted across six TCs located in the region of Andalusia (Spain): Cartaya, Almonte, Mijas, Los Palacios, La Línea, and Tarifa. Participants were 131 patients with cocaine dependence who initiated and finished treatment in TCs between January 2009 and December 2010 (2 years). Cognitive assessment was composed of general measures of executive functioning: Letter Number Sequencing (working memory) and Similarities (reasoning), and executive tasks sensitive to ventromedial prefrontal cortex dysfunction, including the Delis-Kaplan Stroop test (inhibition/cognitive switching), the Revised-Strategy Application Test (strategy application/multitasking), and the Iowa Gambling Task (decision-making). The outcome measure was retention, defined as time in TC treatment (number of days). RESULTS Poor executive functioning significantly predicted shorter treatment retention in cocaine dependent individuals on TC residential treatment (14% of explained variance). Reduced performance on the R-SAT, a multitasking test taxing the ability to develop and apply the best strategy to organize multiple sub-routine tasks in order to achieve a long-term goal, was the most powerful predictor of treatment retention. CONCLUSIONS Self-regulation deficits predict the capacity to remain in residential treatment among cocaine dependents.

Negative urgency, disinhibition and reduced temporal pole gray matter characterize the comorbidity of cocaine dependence and personality disorders ☆

BACKGROUND Individuals with cocaine dependence and co-occurring personality disorders are more likely to have increased impulsivity, dysfunctional beliefs, executive dysfunction and brain structural abnormalities by virtue of the conjoint impact of both pathologies. METHODS We recruited 32 cocaine dependent patients with comorbid Cluster B personality disorders, 44 cocaine dependent patients without comorbidities and 34 non-drug-using controls. They completed the UPPS-P impulsivity scale, the Personality Belief Questionnaire, and executive function tests of working memory, attention/response inhibition and shifting. A subsample (n=61) was also scanned using Magnetic Resonance Imaging. We used univariate ANOVAs for group comparisons, and tested the association between impulsivity, executive control and personality dysfunction and diagnoses using correlation and multivariate logistic regression analyses. RESULTS Cocaine dependent patients with personality disorders had elevated negative urgency and borderline beliefs, decreased inhibition and attention regulation, and reduced temporal pole gray matter with respect to the rest of the sample. Trait and cognitive measures correctly classified 73% of comorbid patients (60% sensitivity and 82% specificity). CONCLUSION The co-occurrence of cocaine dependence and personality disorders is associated with negative-mood impulsivity and beliefs, executive dysfunction and temporal pole attrition.

Disadvantageous Decision-Making as a Predictor of Drop-Out among Cocaine-Dependent Individuals in Long-Term Residential Treatment

Background: The treatment of cocaine-dependent individuals (CDI) is substantially challenged by high drop-out rates, raising questions regarding contributing factors. Recently, a number of studies have highlighted the potential of greater focus on the clinical significance of neurocognitive impairments in treatment-seeking cocaine users. In the present study, we hypothesized that disadvantageous decision-making would be one such factor placing CDI at greater risk for treatment drop-out. Methods: In order to explore this hypothesis, the present study contrasted baseline performance (at treatment onset) on two validated tasks of decision-making, the Iowa Gambling Task (IGT) and the Cambridge Gamble Task (CGT) in CDI who completed treatment in a residential Therapeutic Community (TC) (N = 66) and those who dropped out of TC prematurely (N = 84). Results: Compared to treatment completers, CDI who dropped out of TC prematurely did not establish a consistent and advantageous response pattern as the IGT progressed and exhibited a poorer ability to choose the most likely outcome on the CGT. There were no group differences in betting behavior. Conclusion: Our findings suggest that neurocognitive rehabilitation of disadvantageous decision-making may have clinical benefits in CDI admitted to long-term residential treatment programs.

Polysubstance Use Patterns in Underground Rave Attenders: A Cluster Analysis.

Drug use in mainstream rave parties has been widely documented in a large number of studies. However, not much is known about drug use in underground raves. The purpose of this study is to find out the polysubstance use patterns at underground raves. Two hundred and fifty-two young people between the ages of 18 and 30 who went to underground raves were interviewed. They were given a questionnaire to collect information on drug use at raves. Ravers used a mean of 4.9 different drugs at the last rave they had been to. Over 75% of them used tobacco, alcohol, cannabis, and amphetamine, and over half also used powder ecstasy. Two differentiated use patterns were found: one pattern concentrated more on the use of stimulants and the other on the use of hallucinogens. Underground ravers have a “standard” sociodemographic profile. The use of drugs is much higher than equivalent age group. Higher drug use prevalence than in mainstream rave parties is also observed. Different patterns of use appear which will be necessary to consider in designing preventions and risk reduction strategies.