Impulsivity and executive functions in polysubstance-using rave attenders

Computational modeling of decision-making in substance abusers: testing Bechara's hypotheses

One of the cognitive abilities most affected by substance abuse is decision-making. Behavioral tasks such as the Iowa Gambling Task (IGT) provide a means to measure the learning process involved in decision-making. To comprehend this process, three hypotheses have emerged: (1) participants prioritize gains over losses, (2) they exhibit insensitivity to losses, and (3) the capacity of operational storage or working memory comes into play. A dynamic model was developed to examine these hypotheses, simulating sensitivity to gains and losses. The Linear Operator model served as the learning rule, wherein net gains depend on the ratio of gains to losses, weighted by the sensitivity to both. The study further proposes a comparison between the performance of simulated agents and that of substance abusers (n = 20) and control adults (n = 20). The findings indicate that as the memory factor increases, along with high sensitivity to losses and low sensitivity to gains, agents prefer advantageous alternatives, particularly those with a lower frequency of punishments. Conversely, when sensitivity to gains increases and the memory factor decreases, agents prefer disadvantageous alternatives, especially those that result in larger losses. Human participants confirmed the agents' performance, particularly when contrasting optimal and sub-optimal outcomes. In conclusion, we emphasize the importance of evaluating the parameters of the linear operator model across diverse clinical and community samples.

Breadth of substance use is associated with the selection of a larger food portion size via elevated impulsivity

Substance use is associated with altered or elevated food consumption and disordered eating. In the present study we examined whether breadth (variety) of drug use was associated with elevated portion size in a general population sample as it was in persons in recovery from substance use disorder. Furthermore, measures of emotional eating, impulsivity, food misuse, food craving were taken as possible mediators and reward responsiveness was examined as a potential moderator of this association. 444 adults (48.6 % women, mean age of 47.8 years) completed an online study in which they were asked to make judgements of ideal portion size for 6 different foods using a validated online tool that allowed participants to adjust the portion size of images of foods. Ideal portion size has been identified as a strong predictor of actual consumption. Participants were also asked to report the number of substances used in the past and provide anthropometric information. The results confirmed that breadth of drug use was associated with selection of higher portion size. Reward responsiveness was not a moderator of this relationship. Of the tested mediators, only impulsivity mediated the association between breadth of drug use and portion size. The results show that impulsivity may underlie the association between eating and substance use.

The Relations Between an Inventory-Based Measure of Executive Function and Impulsivity Factors in Alcohol- and Cannabis-Relevant Outcomes

OBJECTIVE

While the lack of relation between performance- and inventory-based executive function (EF) measures is well documented, there remains ambiguity between self-report EFs and closely related constructs (e.g., impulsivity) assessed via the same method. The degree of convergence between purported EF measures with similar yet distinct constructs contain important theoretical implications for available EF assessment strategies and their construct validity. A newer measure of EF, the Behavior Regulation Inventory of Executive Functions-Adult (BRIEF-A), allows for more direct comparisons to self-reported measures of impulsivity, such as the commonly used Urgency, Planning, Perseverance, Sensation Seeking-Positive Urgency (UPPS-P) assessment.

METHOD

The present study used factor analysis and hierarchical regression to explore the associations between the BRIEF-A and UPPS-P, using alcohol and cannabis consumption across various outcomes (i.e., quantity-frequency and consequences) as an external criterion. Participants were 339 undergraduate students (Mage = 19.35; Female = 63%) from a large southwestern university.

RESULTS

The BRIEF-A and UPPS-P demonstrated strong correlations at both higher- and lower order facets. While the BRIEF-A was a significant correlate to many substance use outcomes, these relations were generally weaker than those seen with the UPPS-P. Hierarchical regression suggested limited contributions of the BRIEF-A over and above the UPPS-P.

CONCLUSIONS

Overall, this study suggested substantial overlap between impulsigenic factors and EFs when measured by self-report, and limited utility of EF measures to account for unique variance with substance use outcomes in this sample.

Indirect Associations between Impulsivity and Alcohol Outcomes through Motives for Drinking Responsibly among U.S. College Students: An Integration of Self-Determination Theory and the Acquired Preparedness Model

The aim of the present study was to conduct a preliminary investigation of the associations between facets of impulsivity and alcohol outcomes through motives for drinking responsibly described by self-determination theory among college students. Participants (N=2,808) were part of a multisite investigation of college student drinking across 10 universities in 8 states in the U.S. who reported past-month drinking. Results of a structural equation model testing all possible indirect associations simultaneously indicated that one-third (20 out of 60) of the indirect associations were statistically significant (p<.01). Facets with higher scores representing higher impulsivity (negative/positive urgency) were negatively associated with more internalized motives (autonomous motivation and introjected regulation) and positively associated with less internalized motives (external regulation and amotivation) for drinking responsibly. Facets with higher scores representing lower impulsivity (perseverance and premeditation) demonstrated opposite patterns of associations with motives for drinking responsibly. In turn, more internalized motives were related to higher frequency of protective behavioral strategies use, lower alcohol use severity, and fewer negative alcohol-related consequences; less internalized motives demonstrated an opposite pattern of associations with these alcohol outcomes. The present findings should be replicated using experimental and longitudinal studies for appropriately testing mediation but offer support for a novel hypothesis for motivational pathways from impulsivity to alcohol outcomes that may provide insight into intervention targets.

The role of executive functions, social cognition and intelligence in predicting social adaptation of vulnerable populations

This study sought to evaluate the roles of and interactions between cognitive processes that have been shown to exhibit impact from socioeconomic status (SES) and living conditions in predicting social adaptation (SA) in a population of adults living in socially vulnerable conditions. Participants included 226 people between the ages of 18 and 60 who have been living in vulnerable contexts throughout life in Santiago, Chile. Data was collected through a battery of psychological assessments. A structural equation model (SEM) was implemented to examine the interrelationships among cognitive and social variables. Results indicate a significant relationship between executive function (EF) and SA through both social cognition (SC) and intelligence. Theory of Mind (ToM), a component of SC, was shown to exhibit a significant relationship with affective empathy; interestingly, this was negatively related to SA. Moreover, fluid intelligence (FI) was found to exhibit a positive, indirect relationship with SA through crystallized intelligence (CI). Evaluation of these results in the context of research on the impacts of SES and vulnerable living conditions on psychological function may allow for the development of more effective clinical, political, and social interventions to support psychosocial health among socially vulnerable populations.

Delay discounting and neurocognitive performance in young adults with differential patterns of substance use: Findings from the Human Connectome Project

A large proportion of individuals who use psychoactive substances regularly use more than one substance. This pattern of behavior, termed polysubstance use, is associated with greater risks than when consuming only a single substance. The present study examined delay discounting, neurocognitive functioning, and demographic indicators among a large, racially and socioeconomically diverse sample of young adults drawn from the Human Connectome Project who reported either non, mono, or dual use of alcohol, tobacco, and/or cannabis. Univariate and multivariate tests suggested individuals who reported using multiple substances were more likely to be male, experienced higher rates of alcohol use disorder, and, when reporting both alcohol use and cannabis involvement, scored lower on a measure of inhibitory control relative to those who reported mono or dual use of alcohol and/or cigarettes. Individuals who reported currently smoking cigarettes exhibited the steepest discounting irrespective of other substances used; however, we observed additive effects for alcohol use and, to a lesser extent, cannabis involvement. Specifically, steeper discounting occurred when individuals who reported either regular alcohol use or > 100 lifetime instances of cannabis use also reported smoking cigarettes. We discuss several hypotheses for this finding related to the diversity of the sample and substances assessed as well as directions for future programmatic lines of research. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Relations between impulsive personality traits, alcohol and cannabis co-use, and negative alcohol consequences: A test of cognitive and behavioral mediators

OBJECTIVE

Alcohol and cannabis co-users experience more negative alcohol consequences, but distal and mediating mechanisms of this association remain largely unstudied. Considering research suggests that individuals high in impulsivity and sensation seeking are more likely to be co-users, it is possible that co-users have more positive expectancies and become heavier drinkers, which confer risk for future negative consequences. Therefore, the current study tested prospective mediation models in which impulsive personality traits indirectly predicted negative consequences through co-use, heavier drinking, and expectancies.

METHODS

The current study used data from a study of familial AUD spanning 3 waves (1995-2010). Participants (N = 567) reported on impulsivity (via the Eysenck Personality Inventory and Sensation Seeking Scale) alcohol and cannabis use, alcohol expectancies, and negative consequences. Models tested the factor structure of impulsive personality traits and whether these traits predicted future negative consequences through past-year co-use and drinking/expectancies.

RESULTS

Factor analysis suggested two factors, sensation seeking and lack of premeditation. Sensation seeking was associated with future negative consequences indirectly through co-use and both drinking quantity and positive expectancies. Lack of premeditation was not associated with co-use, but indirectly predicted negative consequences through positive expectancies, above and beyond co-use. Sensation seeking directly predicted negative expectancies, but negative expectancies did not predict negative consequences.

CONCLUSIONS

Impulsive personality traits in co-users, particularly sensation seeking, explained variance in future negative alcohol consequences via heavier drinking (behavior) and positive expectancies (cognition). Personalized interventions targeting a lack of premeditation, and sensation seeking in co-users, may interrupt a developmental trajectory toward problem drinking.

Are methamphetamine users compulsive? Faulty reinforcement learning, not inflexibility, underlies decision making in people with methamphetamine use disorder

Methamphetamine use disorder involves continued use of the drug despite negative consequences. Such 'compulsivity' can be measured by reversal learning tasks, which involve participants learning action-outcome task contingencies (acquisition-contingency) and then updating their behaviour when the contingencies change (reversal). Using these paradigms, animal models suggest that people with methamphetamine use disorder (PwMUD) may struggle to avoid repeating actions that were previously rewarded but are now punished (inflexibility). However, difficulties in learning task contingencies (reinforcement learning) may offer an alternative explanation, with meaningful treatment implications. We aimed to disentangle inflexibility and reinforcement learning deficits in 35 PwMUD and 32 controls with similar sociodemographic characteristics, using novel trial-by-trial analyses on a probabilistic reversal learning task. Inflexibility was defined as (a) weaker reversal phase performance, compared with the acquisition-contingency phases, and (b) persistence with the same choice despite repeated punishments. Conversely, reinforcement learning deficits were defined as (a) poor performance across both acquisition-contingency and reversal phases and (b) inconsistent postfeedback behaviour (i.e., switching after reward). Compared with controls, PwMUD exhibited weaker learning (odds ratio [OR] = 0.69, 95% confidence interval [CI] [0.63-0.77], p < .001), though no greater accuracy reduction during reversal. Furthermore, PwMUD were more likely to switch responses after one reward/punishment (OR = 0.83, 95% CI [0.77-0.89], p < .001; OR = 0.82, 95% CI [0.72-0.93], p = .002) but just as likely to switch after repeated punishments (OR = 1.03, 95% CI [0.73-1.45], p = .853). These results indicate that PwMUD's reversal learning deficits are driven by weaker reinforcement learning, not inflexibility.

How is intolerance of uncertainty related to negative affect in individuals with substance use disorders? The role of the inability to control behaviors when experiencing emotional distress

We used structural equation modeling to assess the role of impaired emotional awareness and clarity (Impaired Awareness/Clarity) and inability to control behaviors when experiencing emotional distress (Inability to Control Behaviors) as an account for the relationship between intolerance of uncertainty (IU) and negative affect (NA) in individuals with Substance Use Disorders (SUDs) and healthy controls (HCs) used for comparison. One-hundred and thirty-one individuals with SUDs (42.75% female; mean age = 39.74 ± 11.83) and 131 sex-matched HCs (mean age = 40.02 ± 12.34) entered the study. Participants completed questionnaires assessing the constructs of interest. Single-group analyses aimed to identify a baseline model for each group and test the hypothesized direct/indirect relations' overall significance. Then, a multigroup analysis tested the invariance of model parameters between SUD and HC groups. The model in which IU had both direct and indirect relationships with NA through Impaired Awareness/Clarity and Inability to Control Behaviors was a good fit to the data. The indirect relationship of IU with NA through Inability to Control Behaviors was significant and moderate-sized. The relationship involving Impaired Awareness/Clarity and Inability to Control Behaviors was small-sized and significant in single group analysis only. The multigroup analysis supported the association of IU with NA through Inability to Control Behaviors in the SUD group. Overall, our study highlights the crucial role of the Inability to Control Behaviors in SUDs and suggests that its association with IU might fuel NA in this population.

Impulsivity and Medical Care Utilization in Veterans Treated for Substance Use Disorder

Impulsivity has been defined by acting rashly during positive mood states (positive urgency; PU) or negative mood states (negative urgency; NU) and by excessive de-valuation of deferred rewards. These behaviors reflect a "live in the now" mentality that is not only characteristic of many individuals with severe substance use disorder (SUD) but also impedes medical treatment compliance and could result in repeated hospitalizations or other poor health outcomes. Purpose/objectives: We sought preliminary evidence that impulsivity may relate to adverse health outcomes in the veteran population. Impulsivity measured in 90 veterans receiving inpatient or outpatient SUD care at a Veterans Affairs Medical Center was related to histories of inpatient/residential care costs, based on VA Health Economics Resource Center data. Results: We found that positive urgency, lack of persistence and lack of premeditation, but not sensation-seeking or preference for immediate or risky rewards, were significantly higher in veterans with a history of one or more admissions for VA-based inpatient or residential health care that either included (n = 30) or did not include (n = 29) an admission for SUD care. Among veterans with a history of inpatient/residential care for SUD, NU and PU, but not decision-making behavior, correlated with SUD care-related costs. Conclusions/Importance: In veterans receiving SUD care, questionnaire-assessed trait impulsivity (but not decision-making) related to greater care utilization within the VA system. This suggests that veterans with high impulsivity are at greater risk for adverse health outcomes, such that expansion of cognitive interventions to reduce impulsivity may improve their health.

Decision making in substance use disorder patients: Reliability, convergent validity and sensitivity to change of a new behavioral measure

OBJECTIVE

The Iowa Gambling Task (IGT) and the Delay Discounting Test (DDT) are two of the most widely used decision-making tests within the field of addiction research. The IGT creates a context of uncertainty where immediate rewards or long-term benefits are chosen, whilst the DDT measures the change in value of a reward as the time taken to obtain it increases. The objective of this study was to analyze the psychometric properties of a new task: Deciding about your health (DAYH), which integrates both components.

METHOD

Longitudinal observational study. The sample was composed of 97 patients being treated for cocaine use disorder. The DAYH, IGT, DDT and other instruments for measuring dependence severity were administered. Relapse was evaluated within 3 and 6 months after the baseline assessment.

RESULTS

Reliability was indicated by an intraclass correlation coefficient (r) of. 80. DAYH scores showed significant relationships with IGT (r = -.237; p <.05), although not with DDT (r =.048) scores. A relationship was also found between DAYH and dependency severity (r = -.213; p <.05) and craving (r = -.231; p <.05). The DAYH scores showed sensitivity to change, and the capacity to predict relapse.

CONCLUSIONS

These findings indicate the utility of DAYH for exploring decision-making in patients with substance use disorders. The relationships with IGT and DDT also indicate the need to further investigate how decisions are made in various contexts of choice.

Unpacking common and distinct neuroanatomical alterations in cocaine dependent versus pathological gambling

Pathological gambling and cocaine dependence are highly pervasive disorders. Functional neuroimaging evidence implicates aberrant activity of prefrontal striatal pathways in both disorders. It is unclear if the neuroanatomy of these areas is also affected. Participants with pathological gambling (n = 18), cocaine dependence (n = 19) and controls (n = 21) underwent high-resolution structural MRI scan and cognitive assessments. In line with emerging functional neuroimaging findings, we hypothesised (i) lower volumes of corticostriatal areas ascribed to decision-making/inhibitory control, craving and reward processing (i.e., orbitofrontal cortex, inferior frontal gyrus, amygdala, striatum, insula) in both pathological gamblers and cocaine dependent participants versus controls; (ii) selected dopaminergic/glutamatergic pathways directly taxed by cocaine (i.e., superior, dorsolateral and anterior cingulate cortices) would be altered in cocaine dependent versus control participants only. Analyses were conducted with a bonferroni correction. Our results showed that both pathological gambling and cocaine dependent participants, compared to controls, had larger volumes of the right inferior frontal gyrus (ps <.01, ds = 0.66 and 0.62). Cocaine dependent participants had lower nucleus accumbens and medial orbitofrontal cortex volumes than pathological gamblers (ps <.05, ds = 0.51 and 0.72), with the latter being predicted by higher negative urgency scores. Inferior frontal gyrus volume may reflect common alterations of cocaine and gambling addictions, whereas cocaine dependence may be uniquely associated with reduced volume in dorsolateral and middle frontal regions. Cocaine's supra-physiological effects on mesolimbic neurons may explain reduced accumbens-orbitofrontal structure compared to gambling.

Working memory reflects vulnerability to early life adversity as a risk factor for substance use disorder in the FKBP5 cortisol cochaperone polymorphism, rs9296158

Early life adversity (ELA) negatively affects health behaviors in adulthood, but pathways from ELA exposure to behavioral outcomes are poorly understood. ELA in childhood and adolescence may translate into adult outcomes by way of modified glucocorticoid signaling. The cortisol cotransporter, FKBP5 has a G-to-A substitution (rs9296158) that hinders cortisol trafficking within target cells, and this impaired glucocorticoid signaling may shape the long-term response to ELA. We used performance on the Stroop test to assess working memory in 546 healthy young adults who had experienced 0, 1, or > 1 forms of ELA in childhood and adolescence and were genotyped for the FKBP5 rs9296158 G-to-A polymorphism. We observed a robust Gene x Environment interaction (F = 9.49, p < .0001) in which increased ELA exposure led to progressively greater Stroop interference in persons carrying AG and AA genotypes of FKBP5 with no such effect in GG carriers. Further work is needed to explore the modification of cognitive function resulting from ELA. Impairments in working memory illustrate how ELA may use glucocorticoid pathways to influence working memory with potential implications for decision-making and risky behavior including substance use disorders.

Effects of reward and punishment on learning from errors in smokers

BACKGROUND

Punishing errors facilitates adaptation in healthy individuals, while aberrant reward and punishment sensitivity in drug-dependent individuals may change this impact. Many societies have institutions that use the concept of punishing drug use behavior, making it important to understand how drug dependency mediates the effects of negative feedback for influencing adaptive behavior.

METHODS

Using an associative learning task, we investigated differences in error correction rates of dependent smokers, compared with controls. Two versions of the task were administered to different participant samples: One assessed the effect of varying monetary contingencies to task performance, the other, the presence of reward as compared to avoidance of punishment for correct performance.

RESULTS

While smokers recalled associations that were rewarded with a higher value 11% more often than lower rewarded locations, they did not correct higher punished locations more often. Controls exhibited the opposite pattern. The three-way interaction between magnitude, feedback type and group was significant, F(1,48) = 5.288, p =0.026, ɳ²p =0.099. Neither participant group corrected locations offering reward more often than those offering avoidances of punishment. The interaction between group and feedback condition was not significant, F(1,58) = 0.0, p =0.99, ɳ²p =0.001.

CONCLUSIONS

The present results suggest that smokers have poorer learning from errors when receiving negative feedback. Moreover, larger rewards reinforce smokers' behavior stronger than smaller rewards, whereas controls made no distinction. These findings support the hypothesis that dependent smokers may respond to positively framed and rewarded anti-smoking programs when compared to those relying on negative feedback or punishment.

Polysubstance use profiles among electronic dance music party attendees in New York City and their relation to use of new psychoactive substances

BACKGROUND

Electronic Dance Music (EDM) party attendees are often polysubstance users and are at high risk for use of new psychoactive substances (NPS). We sought to identify patterns of use of common illegal drugs among EDM party attendees, sociodemographic correlates, and use of NPS as a function of patterns of use of more common drugs to inform prevention and harm reduction.

METHOD

Using time-space-sampling, 1045 individuals aged 18-40 were surveyed entering EDM parties in New York City. We queried past-year use of common illegal drugs and 98 NPS. We conducted latent class analysis to identify polysubstance use profiles of use of eight common drugs (i.e., ecstasy, ketamine, LSD, mushrooms, powder cocaine, marijuana, amphetamine, benzodiazepines). Relationships between drug classification membership and sociodemographics and use of drugs within six NPS categories were examined.

RESULTS

We identified four profiles of use of common drugs: non-polysubstance use (61.1%), extensive polysubstance use (19.2%), moderate polysubstance use/stimulants (12.8%), and moderate polysubstance use/psychedelics (6.7%). Those in the moderate/psychedelic group were at higher odds of using NPS with psychedelic-type effects (2C, tryptamines, and other "new" psychedelics; Ps<0.05). Extensive polysubstance users were at increased odds of reporting use of 2C drugs, synthetic cathinones ("bath salts"), tryptamines, other new (non-phenethylamine) psychedelics, new dissociatives, and synthetic cannabinoids (Ps<0.05).

CONCLUSION

NPS preference is linked to the profile of use of common drugs among individuals in the EDM scene. Most participants were identified as non-polysubstance users, but findings may help inform preventive and harm reduction interventions among those at risk in this scene.

The Role of Working Memory for Cognitive Control in Anorexia Nervosa versus Substance Use Disorder

Prefrontal cortex executive functions, such as working memory (WM) interact with limbic processes to foster impulse control. Such an interaction is referred to in a growing body of publications by terms such as cognitive control, cognitive inhibition, affect regulation, self-regulation, top-down control, and cognitive–emotion interaction. The rising trend of research into cognitive control of impulsivity, using various related terms reflects the importance of research into impulse control, as failure to employ cognitions optimally may eventually result in mental disorder. Against this background, we take a novel approach using an impulse control spectrum model – where anorexia nervosa (AN) and substance use disorder (SUD) are at opposite extremes – to examine the role of WM for cognitive control. With this aim, we first summarize WM processes in the healthy brain in order to frame a systematic review of the neuropsychological, neural and genetic findings of AN and SUD. In our systematic review of WM/cognitive control, we found n = 15 studies of AN with a total of n = 582 AN and n = 365 HC participants; and n = 93 studies of SUD with n = 9106 SUD and n = 3028 HC participants. In particular, we consider how WM load/capacity may support the neural process of excessive epistemic foraging (cognitive sampling of the environment to test predictions about the world) in AN that reduces distraction from salient stimuli. We also consider the link between WM and cognitive control in people with SUD who are prone to ‘jumping to conclusions’ and reduced epistemic foraging. Finally, in light of our review, we consider WM training as a novel research tool and an adjunct to enhance treatment that improves cognitive control of impulsivity.

Impulsive Personality and Alcohol Use: Bidirectional Relations Over One Year

OBJECTIVE

Impulsive personality traits have been found to be robust predictors of substance use and problems in both cross-sectional and longitudinal research. Studies examining the relations of substance use and impulsive personality over time indicate a bidirectional relation, where substance use is also predictive of increases in later impulsive personality. The present study sought to build on these findings by examining the bidirectional relations among the different impulsive personality traits assessed by the UPPS-P Impulsive Behavior Scale, with an interest in urgency (the tendency to act rashly when experiencing strong affect).

METHOD

Participants were 525 first-year college students (48.0% male, 81.1% White), who completed self-report measures assessing personality traits and a structured interview assessing past and current substance use. Data collection took place at two different time points: the first occurred during the participants' first year of college, and the second occurred approximately 1 year later. Bidirectional relations were examined using structural equation modeling.

RESULTS

Time 1 (T1) positive urgency predicted higher levels of alcohol use at Time 2 (T2), whereas T1 lack of perseverance predicted lower levels of alcohol use at T2. T1 alcohol use predicted higher levels of positive urgency, negative urgency, sensation seeking, and lack of premeditation at T2.

CONCLUSIONS

Findings provide greater resolution in characterizing the bidirectional relation between impulsive personality traits and substance use.

Understanding the Psychosocial Correlates of the Intention to Use Condoms among Young Men in KwaZulu-Natal, South Africa

South Africa leads the world with the number of people infected with HIV. Even with all attempts that have been made to curb HIV, it is still evident that new infections are on the rise. Condom use remains one of the best tools against this challenge yet a small number of sexually active men use them. This study investigates the psychosocial correlates of the intention to use condoms among young men in KwaZulu-Natal province. Using the Theory of Planned Behaviour as a framework, hierarchical linear regression models were used to determine the unique contribution of the study measures in explaining the overall variance of intention to consistently use condoms. Subjective norms and perceived behavioural control towards consistent condom use explained 46% of the variance in the intention to use a condom, suggesting that health behaviour interventions should focus on targeting the normative beliefs as well as control beliefs of the target population. Furthermore, subjective norms and intentions towards reducing alcohol and marijuana use explained an additional 7% to the final model in intentions to condom use, implying that substance use and condom usage may influence each other. No significant contributions were found for beliefs underlying cultural aspects of responsible manhood.

Exploring associations between self-regulatory mechanisms and neuropsychological functioning and driver behaviour after brain injury

The objective of this prospective one-year follow-up study was to explore the associations between self-regulatory mechanisms and neuropsychological tests as well as baseline and follow-up ratings of driver behaviour. The participants were a cohort of subjects with stroke and traumatic brain injury (TBI) who were found fit to drive after a multi-disciplinary driver assessment (baseline). Baseline measures included neuropsychological tests and ratings of self-regulatory mechanisms, i.e., executive functions (Behavior Rating Inventory of Executive Function-Adult Version; BRIEF-A) and impulsive personality traits (UPPS Impulsive Behavior Scale). The participants rated pre-injury driving behaviour on the Driver Behaviour Qestionnaire (DBQ) retrospectively at baseline and after one year of post-injury driving (follow-up). Better performance on neuropsychological tests was significantly associated with more post-injury DBQ Violations. The BRIEF-A main indexes were significantly associated with baseline and follow-up ratings of DBQ Mistakes and follow-up DBQ Inattention. UPPS (lack of) Perseverance was significantly associated with baseline DBQ Inattention, whereas UPPS Urgency was significantly associated with baseline DBQ Inexperience and post-injury DBQ Mistakes. There were no significant changes in DBQ ratings from baseline (pre-injury) to follow-up (post-injury). It was concluded that neuropsychological functioning and self-regulatory mechanisms are related to driver behaviour. Some aspects of driver behaviour do not necessarily change after brain injury, reflecting the influence of premorbid driving behaviour or impaired awareness of deficits on post-injury driving behaviour. Further evidence is required to predict the role of self-regulatory mechanisms on driver behaviour and crashes or near misses.

Impulsivity and risk for prescription opioid misuse in a chronic pain patient sample

Misuse of, and addiction to, prescription opioid pain relievers is a growing concern, in both non-clinical samples and chronic pain patients receiving opioid analgesic therapy. Research is needed to identify which patients may be more prone to misuse or dependence on opioids in a chronic pain treatment setting. Based on literature showing the role of impulsivity in substance use disorders generally, we predicted that impulsivity may also be important to understanding which individuals may be at risk for opioid misuse when opioids are prescribed for pain. The present study examined associations between impulsivity facets and measures of prescription opioid misuse and symptoms. Four facets of impulsivity were examined: urgency, sensation seeking, lack of premeditation, and lack of perseverance. 143 patients receiving treatment for chronic pain at a regional pain clinic completed a series of questionnaires including the UPPS and measures of opioid risk and misuse. Consistent with predictions, urgency was associated with risk for future misuse (β=0.246, p<0.05), current misuse (β=0.253, p<0.01), and symptoms of current opioid use disorder (OUD; β=0.206, p<0.05). Sensation seeking was also associated with current misuse (β=0.279, p<0.01). These results suggest that identifying facets of impulsivity is important to understanding and assessing for risk of prescription opioid misuse in the context of chronic pain treatment. These data indicate that patients who react impulsively to negative mood states and cravings may be especially prone to developing aberrant use patterns when taking prescription opioids. This is the first known study to identify the role of urgency in predicting risk for OUDs in chronic pain patients.

Negative urgency, mood induction, and alcohol seeking behaviors

BACKGROUND

Negative urgency, defined as impulsive risk-taking during extreme negative emotional states, is the most important impulsivity-related trait for alcohol-related problems and alcohol dependence. However, how negative urgency imparts risk for alcohol-related problems is not yet well understood. Therefore, the goal of the current study was to examine how negative urgency relates to separable aspects of the emotional experience and alcohol-seeking behaviors.

METHODS

A total of 34 (19 women) community-dwelling, alcohol-using adults aged 21-32 (mean age=24.86, SD=3.40, 74.3% Caucasian) completed two counterbalanced intravenous alcohol self-administration sessions: one during a neutral mood condition and one during a negative mood condition.

RESULTS

Negative urgency was associated with 1) greater mood change following negative mood induction (F=4.38, df=15, p=0.002, η2=0.87), but was unrelated to changes in craving or cortisol release in response to mood induction; 2) greater alcohol craving prior to and after an alcohol prime (F=3.27, p=0.02, η2=0.86), but only in the negative and not the neutral mood condition; and 3) higher peak BrAC (F=2.13, df=42, p=0.02, η2=0.48), continuing to increase intoxication level over a longer period (F=3.77, df=42, p<0.001, η2=0.62), and more alcohol seeking (F=21.73, df=22, p<0.001, η2=0.94) throughout the negative session. Negative urgency was associated with overall lower cortisol release.

CONCLUSIONS

These results highlight the importance of assessing behavioral indicators of negative urgency under mood condition, and suggest that negative urgency may amplify alcohol self-administration through increased negative emotional reactivity to mood events and increased alcohol craving after initial alcohol exposure, leading to maintenance of alcohol related behavior.

The psychosocial determinants of the intention to avoid sexual engagement when intoxicated among young men in KwaZulu-Natal, South Africa

BACKGROUND

A cross sectional study was conducted among 350 sexually active, mainly unemployed men between the ages of 18 and 35 in KwaZulu-Natal. This study examined the psychosocial determinants of the intention to be sexually active after having used marijuana or alcohol personally or in instances when the sexual partner is intoxicated. The theory of planned behaviour and cultural notions of responsible manhood were used in developing the measures.

METHODS

Correlation and hierarchical stepwise linear regression analyses tested determinants of the intention to avoid having sex when personally intoxicated and the intention to avoid sex when the sexual partner is intoxicated.

RESULTS

About 78 % of the participants reported regular use of alcohol and 39 % indicated ever-using marijuana. A total of 36.3 % used both alcohol and marijuana, and 73 % said that they engaged in multiple sexual partner behaviour. The intention to avoid sex when personally intoxicated as well as the intention to avoid sex when the sexual partner is intoxicated were significantly associated with subjective norms and perceptions of perceived behavioural control towards the respective behaviours, and less with attitudes towards the respective behaviours.

CONCLUSIONS

These findings imply that health education interventions should focus on changing the normative beliefs as well as control beliefs of the target population either directly through education and training or indirectly by creating physical and social environments that facilitate safe sexual practices, for example by organizing positive peer support for risk prevention and by making condoms freely available in community alcohol serving establishments.

Working memory, executive function and impulsivity in Internet-addictive disorders: a comparison with pathological gambling

OBJECTIVE

The purpose of the present study was to test whether individuals with Internet addiction disorder (IAD) presented analogous characteristics of working memory, executive function and impulsivity compared with pathological gambling (PG) patients.

METHODS

The subjects included 23 individuals with IAD, 23 PG patients and 23 controls. All of the participants were measured with the digit span task, Wisconsin Card Sorting Test, go/no-go task and Barratt Impulsiveness Scale-11 (BIS-11) under the same experimental conditions.

RESULTS

The results of this study showed that the false alarm rate, total response errors, perseverative errors, failure to maintain set and BIS-11 scores of both the IAD and PG groups were significantly higher than that of the control group. In addition, the forward scores and backwards scores, percentage of conceptual level responses, number of categories completed and hit rate of the IAD and PG groups were significantly lower than that of the control group. Furthermore, the false alarm rate and BIS-11 scores of the IAD group were significantly higher than those of PG patients, and the hit rate was significantly lower than that of the PG patients.

CONCLUSIONS

Individuals with IAD and PG patients present deficiencies in working memory, executive dysfunction and impulsivity, and individuals with IAD are more impulsive than PG patients.

Electrophysiology for addiction medicine: From methodology to conceptualization of reward deficits

In the past decade, electroencephalographic research on addiction has employed passive viewing, oddball, inhibition, prediction, gambling, and reversal learning tasks to study how substance users neurally prioritize drug-related rewards at the expense of nondrug rewards. On the whole, findings across substances (alcohol, cannabis, cocaine, nicotine, opiates, gambling, and gaming) demonstrate impairments in the differentiation of monetary incentives and the inhibition of prepotent responses. Furthermore, exaggerated resources devoted to drug cues and attenuated processing of other types of pleasant emotional stimuli predict greater probability of future drug use. However, drug use recency, frequency, sensitivity, and insight all appear to be moderators of these effects. We argue that more longitudinal studies are warranted to determine the time course of reward processing as a function of development and chronicity.

Impaired decision-making under risk is associated with gaming-specific inhibition deficits among college students with Internet gaming disorder

A growing body of evidence indicates that both inhibition and decision-making deficits play essential roles in the development and maintenance of Internet gaming disorder (IGD). Clarifying whether impaired decision-making among individuals with IGD is related to poor inhibition will advance our understanding of IGD and contribute to intervention development. However, the relationship between these two functions remains unclear. In this study, we sought to systemically examine inhibitory processes, decision-making and the relationship between the two among individuals with IGD. Thirty-four individuals with IGD and 32 matched healthy controls (HCs) were recruited. In comparison to HCs, IGD subjects demonstrated inhibition deficits during performance of the gaming-related Go/No-Go task and impaired decision-making under risk. In addition, errors on No-Go trials during the gaming-related Go/No-Go task were positively associated with decision-making impairments under risk but not under ambiguity among IGD subjects. These results suggest individuals with IGD are impaired in some aspects of inhibition and decision-making functions, and that decision-making deficits under risk are linked to poor inhibition specifically related to gaming cues, which has implications for the development of novel intervention.

Cocaine use severity and cerebellar gray matter are associated with reversal learning deficits in cocaine-dependent individuals

Cocaine addiction involves persistent deficits to unlearn previously rewarded response options, potentially due to neuroadaptations in learning-sensitive regions. Cocaine-targeted prefrontal systems have been consistently associated with reinforcement learning and reversal deficits, but more recent interspecies research has raised awareness about the contribution of the cerebellum to cocaine addiction and reversal. We aimed at investigating the link between cocaine use, reversal learning and prefrontal, insula and cerebellar gray matter in cocaine-dependent individuals (CDIs) varying on levels of cocaine exposure in comparison with healthy controls (HCs). Twenty CDIs and 21 HCs performed a probabilistic reversal learning task (PRLT) and were subsequently scanned in a 3-Tesla magnetic resonance imaging scanner. In the PRLT, subjects progressively learn to respond to one predominantly reinforced stimulus, and then must learn to respond according to the opposite, previously irrelevant, stimulus-reward pairing. Performance measures were errors after reversal (reversal cost), and probability of maintaining response after errors. Voxel-based morphometry was conducted to investigate the association between gray matter volume in the regions of interest and cocaine use and PRLT performance. Severity of cocaine use correlated with gray matter volume reduction in the left cerebellum (lobule VIII), while greater reversal cost was correlated with gray matter volume reduction in a partially overlapping cluster (lobules VIIb and VIII). Right insula/inferior frontal gyrus correlated with probability of maintaining response after errors. Severity of cocaine use detrimentally impacted reversal learning and cerebellar gray matter.

Recent Translational Findings on Impulsivity in Relation to Drug Abuse

Impulsive behavior is strongly implicated in drug abuse, as both a cause and a consequence of drug use. To understand how impulsive behaviors lead to and result from drug use, translational evidence from both human and non-human animal studies is needed. Here, we review recent (2009 or later) studies that have investigated two major components of impulsive behavior, inhibitory control and impulsive choice, across preclinical and clinical studies. We concentrate on the stop-signal task as the measure of inhibitory control and delay discounting as the measure of impulsive choice. Consistent with previous reports, recent studies show greater impulsive behavior in drug users compared with non-users. Additionally, new evidence supports the prospective role of impulsive behavior in drug abuse, and has begun to identify the neurobiological mechanisms underlying impulsive behavior. We focus on the commonalities and differences in findings between preclinical and clinical studies, and suggest future directions for translational research.

Behavioural ratings of self-regulatory mechanisms and driving behaviour after an acquired brain injury

OBJECTIVE

To explore whether measurements of self-regulatory mechanisms and cognition predict driving behaviour after an acquired brain injury (ABI).

DESIGN

Consecutive follow-up study.

PARTICIPANTS

At baseline participants included 77 persons with stroke and 32 persons with a traumatic brain injury (TBI), all of whom completed a multidisciplinary driving assessment (MDA). A follow-up cohort of 34 persons that succeeded the MDA was included. Baseline measurements: Neuropsychological tests and measurements of self-regulatory mechanisms (BRIEF-A and UPPS Impulsive Behaviour Scale), driving behaviour (DBQ) and pre-injury driving characteristics (mileage, compensatory driving strategies and accident rates). Follow-up measurements: Post-injury driving characteristics were collected by mailed questionnaires from the participants who succeeded the MDA.

METHODS

A MDA, which included a medical examination, neuropsychological testing and an on-road driving test, was considered in the decision for or against granting a driver's license. Self-regulatory mechanisms and driving behaviour were examined for research purposes only.

RESULTS

At baseline, self-regulatory mechanisms were significantly associated to aberrant driving behaviour, but not with neuropsychological data or with the outcome of the on-road driving test. Aspects of self-regulation were associated to driving behaviour at follow-up.

CONCLUSION

It is recommended that self-regulatory measurements should regularly be considered in the driving assessments after ABI.

Unique aspects of impulsive traits in substance use and overeating: specific contributions of common assessments of impulsivity

Abstract Background: Impulsivity is a complex trait often studied in substance abuse and overeating disorders, but the exact nature of impulsivity traits and their contribution to these disorders are still debated. Thus, understanding how to measure impulsivity is essential for comprehending addictive behaviors.

OBJECTIVES

Identify unique impulsivity traits specific to substance use and overeating.

METHODS

Impulsive Sensation Seeking (ImpSS) and Barratt's Impulsivity scales (BIS) Scales were analyzed with a non-parametric factor analytic technique (discriminant correspondence analysis) to identify group-specific traits on 297 individuals from five groups: Marijuana (n = 88), Nicotine (n = 82), Overeaters (n = 27), Marijuauna + Nicotine (n = 63), and CONTROLs (n = 37).

RESULTS

A significant overall factor structure revealed three components of impulsivity that explained respectively 50.19% (pperm < 0.0005), 24.18% (pperm < 0.0005), and 15.98% (pperm < 0.0005) of the variance. All groups were significantly different from one another. When analyzed together, the BIS and ImpSS produce a multi-factorial structure that identified the impulsivity traits specific to these groups. The group specific traits are (1) CONTROL: low impulse, avoids thrill-seeking behaviors; (2) Marijuana: seeks mild sensation, is focused and attentive; (3) Marijuana + Nicotine: pursues thrill-seeking, lacks focus and attention; (4) Nicotine: lacks focus and planning; (5) Overeating: lacks focus, but plans (short and long term).

CONCLUSIONS

Our results reveal impulsivity traits specific to each group. This may provide better criteria to define spectrums and trajectories - instead of categories - of symptoms for substance use and eating disorders. Defining symptomatic spectrums could be an important step forward in diagnostic strategies.

Are sexes affected differently by ketamine? An exploratory study in ketamine users

One hundred primary ketamine users and 100 controls were recruited in Hong Kong between December 2009 and December 2011. Cognitive assessment included general intelligence, working, verbal, and visual memory, and executive functions. A Univariate General Linear Model was used to compare cognitive performance between the male and female ketamine users and controls. The female users appeared to have a higher risk of visual memory impairment than their male counterparts. Further studies are warranted to clarify the mechanism of the sex-specific effect of ketamine on cognitive functions.

Cognitive impairments in poly-drug ketamine users

RATIONALE

Cognitive impairment has been found to be reversible in people with substance abuse, particularly those using ketamine. Ketamine users are often poly-substance users. This study compared the cognitive functions of current and former ketamine users who were also abusing other psychoactive substances with those of non-users of illicit drugs as controls.

METHODS

One hundred ketamine poly-drug users and 100 controls were recruited. Drug users were divided into current (n = 32) and ex-users (n = 64) according to the duration of abstinence from ketamine (>30 days). The Beck Depression Inventory (BDI), the Hospital Anxiety Depression Scale (HADSA) and the Severity of Dependence Scale (SDS) were used to evaluate depression and anxiety symptoms and the severity of drug use, respectively. The cognitive test battery comprised verbal memory (Wechsler Memory Scale III: Logic Memory and Word List), visual memory (Rey-Osterrieth Complex Figure, ROCF), executive function (Stroop, Wisconsin Card Sorting Test, and Modified Verbal Fluency Test), working memory (Digit Span Backward), and general intelligence (Information, Arithmetic and Digit-Symbol Coding) tests.

RESULTS

Current users had higher BDI and HADSA scores than ex-users (p < 0.001 for BDI and p = 0.022 for HADSA) and controls (p < 0.001 for BDI and p = 0.002 for HADSA). Ex-users had higher BDI (p = 0.006) but equal HADSA scores (p = 1.000) compared to controls. Both current and ex-users had lower scores on Logical Memory delayed recall (p = 0.038 for current users and p = 0.032 for ex-users) and ROCF delayed recall (p = 0.033 for current users and p = 0.014 for ex-users) than controls. Current users also performed worse on ROCF recognition than controls (p = 0.002). No difference was found between the cognitive functions of current and ex-users.

CONCLUSIONS

Ketamine poly-drug users displayed predominantly verbal and visual memory impairments, which persisted in ex-users. The interactive effect of ketamine and poly-drug use on memory needs further investigation.

Latent class analysis of polysubstance use, sexual risk behaviors, and infectious disease among South African drug users

BACKGROUND

HIV transmission risk among non-injection drug users is high due to the co-occurrence of drug use and sexual risk behaviors. The purpose of the current study was to identify patterns of drug use among polysubstance users within a high HIV prevalence population.

METHODS

The study sample included 409 substance users from the Pretoria region of South Africa. Substances used by 20% or more the sample included: cigarettes, alcohol, marijuana and heroin in combination, marijuana and cigarettes in combination, and crack cocaine. Latent class analysis was used to identify patterns of polysubstance use based on types of drugs used. Multivariate logistic regression analyses compared classes on demographics, sexual risk behavior, and disease status.

RESULTS

Four classes of substance use were found: MJ+Cig (40.8%), MJ+Her (30.8%), Crack (24.7%), and Low Use (3.7%). The MJ+Cig class was 6.7 times more likely to use alcohol and 3 times more likely to use drugs before/during sex with steady partners than the Crack class. The MJ+Cig class was 16 times more likely to use alcohol before/during sex with steady partners than the MJ+Her class. The Crack class was 6.1 times more likely to engage in transactional sex and less likely to use drugs before/during steady sex than the MJ+Her class.

CONCLUSIONS

Findings illustrate patterns of drug use among a polysubstance using population that differ in sexual risk behavior. Intervention strategies should address substance use, particularly smoking as a route of administration (ROA), and sexual risk behaviors that best fit this high-risk population.

Cocaine Dependent Individuals and Gamblers Present Different Associative Learning Anomalies in Feedback-Driven Decision Making: A Behavioral and ERP Study

Several recent studies have demonstrated that addicts behave less flexibly than healthy controls in the probabilistic reversal learning task (PRLT), in which participants must gradually learn to choose between a probably rewarded option and an improbably rewarded one, on the basis of corrective feedback, and in which preferences must adjust to abrupt reward contingency changes (reversals). In the present study, pathological gamblers (PG) and cocaine dependent individuals (CDI) showed different learning curves in the PRLT. PG also showed a reduced electroencephalographic response to feedback (Feedback-Related Negativity, FRN) when compared to controls. CDI's FRN was not significantly different either from PG or from healthy controls. Additionally, according to Standardized Low-Resolution Electromagnetic Tomography analysis, cortical activity in regions of interest (previously selected by virtue of their involvement in FRN generation in controls) strongly differed between CDI and PG. However, the nature of such anomalies varied within-groups across individuals. Cocaine use severity had a strong deleterious impact on the learning asymptote, whereas gambling intensity significantly increased reversal cost. These two effects have remained confounded in most previous studies, which can be hiding important associative learning differences between different populations of addicts.

Δ(9)Tetrahydrocannabinol impairs reversal learning but not extra-dimensional shifts in rhesus macaques

Expansion of medical marijuana use in the US and the recently successful decriminalization of recreational marijuana in two States elevates interest in the specific cognitive effects of Δ(9)tetrahydrocannabinol (Δ(9)THC), the major psychoactive constituent of marijuana. Controlled laboratory studies in nonhuman primates provide mixed evidence for specific effects of Δ(9)THC in learning and memory tasks, with a suggestion that frontal-mediated tasks may be the most sensitive. In this study, adult male rhesus monkeys were trained on tasks which assess reversal learning, extradimensional attentional shift learning and spatial delayed-response. Subjects were challenged with 0.1-0.5mg/kg Δ(9)THC, i.m., in randomized order and evaluated on the behavioral measures. Peak plasma levels of Δ(9)THC were observed 30min after 0.2mg/kg (69±29ng/ml) and 60min after 0.5mg/kg (121±23ng/ml) was administered and behavioral effects on a bimanual motor task persisted for up to 2h after injection. An increase in errors-to-criterion (ETC) associated with reversal learning was further increased by Δ(9)THC in a dose-dependent manner. The increase in ETC associated with extradimensional shifts was not affected by Δ(9)THC. Spatial delayed-response performance was impaired by Δ(9)THC in a retention-interval-dependent manner. Overall the pattern of results suggests a more profound effect of Δ(9)THC on tasks mediated by orbitofrontal (reversal learning) versus dorsolateral (extradimensional shifts) prefrontal mechanisms.

The detrimental effects of emotional process dysregulation on decision-making in substance dependence

Substance dependence is complex and multifactorial, with many distinct pathways involved in both the development and subsequent maintenance of addictive behaviors. Various cognitive mechanisms have been implicated, including impulsivity, compulsivity, and impaired decision-making. These mechanisms are modulated by emotional processes, resulting in increased likelihood of initial drug use, sustained substance dependence, and increased relapse during periods of abstinence. Emotional traits, such as sensation-seeking, are risk factors for substance use, and chronic drug use can result in further emotional dysregulation via effects on reward, motivation, and stress systems. We will explore theories of hyper and hypo sensitivity of the brain reward systems that may underpin motivational abnormalities and anhedonia. Disturbances in these systems contribute to the biasing of emotional processing toward cues related to drug use at the expense of natural rewards, which serves to maintain addictive behavior, via enhanced drug craving. We will additionally focus on the sensitization of the brain stress systems that result in negative affect states that continue into protracted abstinence that is may lead to compulsive drug-taking. We will explore how these emotional dysregulations impact upon decision-making controlled by goal-directed and habitual action selections systems, and, in combination with a failure of prefrontal inhibitory control, mediate maladaptive decision-making observed in substance dependent individuals such that they continue drug use in spite of negative consequences. An understanding of the emotional impacts on cognition in substance dependent individuals may guide the development of more effective therapeutic interventions.

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 Cohen's 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.

Refining the measurement of distress intolerance

Distress intolerance is an important transdiagnostic variable that has long been implicated in the development and maintenance of psychological disorders. Self-report measurement strategies for distress intolerance (DI) have emerged from several different models of psychopathology and these measures have been applied inconsistently in the literature in the absence of a clear gold standard. The absence of a consistent assessment strategy has limited the ability to compare across studies and samples, thus hampering the advancement of this research agenda. This study evaluated the latent factor structure of existing measures of DI to examine the degree to which they are capturing the same construct. Results of confirmatory factor analysis in three samples totaling 400 participants provided support for a single-factor latent structure. Individual items of these four scales were then correlated with this factor to identify those that best capture the core construct. Results provided consistent support for 10 items that demonstrated the strongest concordance with this factor. The use of these 10 items as a unifying measure in the study of DI and future directions for the evaluation of its utility are discussed.

Premorbid and current neuropsychological function in opiate abusers receiving treatment

BACKGROUND

There is an established corpus of evidence linking substance abuse with neuropsychological impairment, particularly implicating frontal lobe functions. These could potentially be premorbid to, rather than consequences of, direct effects of substance abuse.

METHODS

A matched pairs design was employed in which currently abstinent opiate abusers in treatment were matched to 22 healthy control individuals. These were compared for premorbid and current neurobehavioral abnormalities with the self-report Frontal Systems Behavior Scale (FrSBe). Estimated premorbid and current IQ scores were also ascertained.

RESULTS

There was no difference between the groups regarding socioeconomic background. There was no evidence for an alteration in cognitive function as measured by current IQ associated with opiate abuse, nor evidence of premorbidly lower IQ. However, with the FrSBe, the opiate abusers reported overall higher levels of apathy. They also had raised FrSBe total scores, indicating the presence of neurobehavioral features associated with frontal lobe impairment. Furthermore, the opiate abusers reported higher levels of these neurobehavioral abnormalities compared to their matched controls, even in the period preceding substance abuse.

CONCLUSIONS

The results suggest that some substance abusing individuals in treatment demonstrate raised levels of neurobehavioral abnormalities, independently of general intellectual functioning. Furthermore, the results imply that these abnormalities may have already been present prior to the effects on the nervous system of substance abuse.

Alcohol-related context modulates performance of social drinkers in a visual Go/No-Go task: a preliminary assessment of event-related potentials

Background

Increased alcohol cue-reactivity and altered inhibitory processing have been reported in heavy social drinkers and alcohol-dependent patients, and are associated with relapse. In social drinkers, these two processes have been usually studied separately by recording event-related potentials (ERPs) during rapid picture presentation. The aim of our study was to confront social drinkers to a task triggering high alcohol cue-reactivity, to verify whether it specifically altered inhibitory performance, by using long-lasting background picture presentation.

Methods

ERP were recorded during visual Go/No-Go tasks performed by social drinkers, in which a frequent Go signal (letter “M”), and a rare No-Go signal (letter “W”) were superimposed on three different types of background pictures: neutral (black background), alcohol-related and non alcohol-related.

Results

Our data suggested that heavy social drinkers made more commission errors than light drinkers, but only in the alcohol-related context. Neurophysiologically, this was reflected by a delayed No-Go P3 component.

Conclusions

Elevated alcohol cue-reactivity may lead to poorer inhibitory performance in heavy social drinkers, and may be considered as an important vulnerability factor in developing alcohol misuse. Prevention programs should be designed to decrease the high arousal of alcohol stimuli and strengthen cognitive control in young, at-risk individuals.

Neuropsychological profiling of impulsivity and compulsivity in cocaine dependent individuals

RATIONALE

Research on the relative impact of trait impulsivity vs. drug exposure on neuropsychological probes of response inhibition vs. response perseveration has been posited as a valid pathway to explore the transition between impulsivity and compulsivity on psychostimulant dependence.

OBJECTIVES

The objectives of this study are to examine performance differences between cocaine-dependent individuals (CDI) and healthy comparison individuals (HCI) on neuropsychological probes of inhibition and perseveration and to examine the predictive impact of trait impulsivity-a proxy of premorbid vulnerability, and severity of cocaine use-a proxy of drug exposure, on CDI's performance.

METHODS

Forty-two CDI and 65 HCI were assessed using the UPPS-P Scale (trait impulsivity), the Stroop and go/no-go (inhibition) and revised-strategy application and probabilistic reversal tests (perseveration).

RESULTS

CDI, compared to HCI, have elevated scores on trait impulsivity and perform significantly poorer on inhibition and perseveration, with specific detrimental effects of duration of cocaine use on perseveration.

CONCLUSIONS

CDI have both inhibition and perseveration deficits; both patterns were broadly indicative of orbitofrontal dysfunction in the context of reinforcement learning. Impulsive personality and cocaine exposure jointly contribute to deficits in response perseveration or compulsivity.

Avaliação da memória operacional fonológica e impulsividade de usuários de drogas atendidos em um Centro de Atenção Integrada à Saúde Mental

OBJETIVO: avaliar a memória operacional fonológica e relacionar com a impulsividade de pacientes em tratamento no Centro de Atenção Integrada à Saúde Mental. MÉTODO: 29 usuários: 21 do gênero masculino e 8 do feminino, usuários de substâncias psicoativas, com 37,9±10,5 anos de idade e 10,59±3,53 anos de escolaridade; e 30 voluntários: 19 do gênero masculino e 11 do feminino, com 32,4±11,9 anos de idade e 11,07±3,29 anos de escolaridade, sem histórico psiquiátrico ou de dependência química foram convocados à avaliação de: 1) memória operacional para palavras e pseudo-palavras; 2) impulsividade em seus fatores de segunda ordem (impulsividade atencional, motora e de não planejamento). RESULTADOS: o desempenho dos usuários de substâncias psicoativas na avaliação da memória em comparação ao grupo controle foi pior tanto no span auditivo de palavras e pseudo-palavras como também no número total de recordação de palavras e pseudo-palavras. Na avaliação da impulsividade, os usuários apresentaram escores elevados em contraposição aos sujeitos controle em todos os subtipos de impulsividade, inclusive no total. Na análise de correlação dos dados não foram encontradas relações entre os escores de impulsividade e memória. CONCLUSÃO: : este padrão de respostas indica comprometimento da memória operacional fonológica provavelmente independente do alto nível de impulsividade apresentado pelos usuários de drogas. Estas análises contribuem para propor estratégias de tratamento direcionadas às alterações detectadas.

Delay-discounting among homeless, out-of-treatment, substance-dependent men who have sex with men

BACKGROUND

Impulsivity is associated with substance use; however, to date, impulsivity has not been characterized among a sample of homeless, non-treatment seeking, substance-dependent men who have sex with men (MSM).

OBJECTIVES

The aim of this study was to utilize the delay-discounting instrument to assess impulsive behaviors among a subsample of homeless, non-treatment seeking, substance-dependent men who have sex with men (S-D MSM) enrolled in a randomized, controlled, contingency management (CM) trial.

METHODS

Twenty S-D MSM participants from the CM parent study were matched on age and ethnicity to 20 non-substance-dependent, non-homeless control participants using propensity scores (N=40) and were administered the delay-discounting procedure.

RESULTS

Although discounting values decreased rapidly with time in both groups, the S-D MSM participants consistently discounted rewards more steeply than controls (p=.05), particularly at all intermediate measured timeframes. The S-D MSM participants also presented greater median discounting rates (k values) compared with the control group (m(S-D MSM)=2.39 (SD=3.72) vs. m(ctrl)=1.27 (SD=3.71), p≤.01).

CONCLUSION

This work extends existing findings of increased delay-discounting among substance-dependent individuals to homeless, substance-dependent, non-treatment seeking MSM.

SCIENTIFIC SIGNIFICANCE

A better understanding of the prevalence of delay-discounting type behaviors among homeless, substance-dependent MSM can be used to inform the development of tailored substance abuse interventions for this high-risk population.