The Role of Executive Cognitive Functions in Changing Substance Use: What We Know and What We Need to Know

Prefrontal Gray Matter and Motivation for Treatment in Cocaine-Dependent Individuals with and without Personality Disorders

Addiction treatment is a long-term goal and therefore prefrontal-striatal regions regulating goal-directed behavior are to be associated with individual differences on treatment motivation. We aimed at examining the association between gray matter volumes in prefrontal cortices and striatum and readiness to change at treatment onset in cocaine users with and without personality disorders. Participants included 17 cocaine users without psychiatric comorbidities, 17 cocaine users with Cluster B disorders, and 12 cocaine users with Cluster C disorders. They completed the University of Rhode Island Change Assessment Scale, which measures four stages of treatment change (precontemplation, contemplation, action, and maintenance) and overall readiness to change, and were scanned in a 3 T MRI scanner. We defined three regions of interest (ROIs): the ventromedial prefrontal cortex (including medial orbitofrontal cortex and subgenual and rostral anterior cingulate cortex), the dorsomedial prefrontal cortex (i.e., superior medial frontal cortex), and the neostriatum (caudate and putamen). We found that readiness to change correlated with different aspects of ventromedial prefrontal gray matter as a function of diagnosis. In cocaine users with Cluster C comorbidities, readiness to change positively correlated with gyrus rectus gray matter, whereas in cocaine users without comorbidities it negatively correlated with rostral anterior cingulate cortex gray matter. Moreover, maintenance scores positively correlated with dorsomedial prefrontal gray matter in cocaine users with Cluster C comorbidities, but negatively correlated with this region in cocaine users with Cluster B and cocaine users without comorbidities. Maintenance scores also negatively correlated with dorsal striatum gray matter in cocaine users with Cluster C comorbidities. We conclude that the link between prefrontal-striatal gray matter and treatment motivation is modulated by co-existence of personality disorders.

An FMRI study of the influence of a history of substance abuse on working memory-related brain activation in schizophrenia

There has been little investigation of the effects of past substance abuse (SA) on working memory (WM) impairments in schizophrenia. This study examined the behavioral and neurobiological impact of past SA (6 months or longer abstinence period) on WM in schizophrenia. Thirty-seven schizophrenia patients (17 with past SA and 20 without) and 32 controls (12 with past SA and 20 without) completed two versions of a two-back WM task during fMRI scanning on separate days. Analyses focused on regions whose patterns of activation replicated across both n-back tasks. Schizophrenia patients were significantly less accurate than controls on both n-back tasks. No main effects or interactions with past SA on WM performance were observed. However, several fronto-parietal-thalamic regions showed an interaction between diagnostic group and past SA. These regions were significantly more active in controls with past SA compared to controls without past SA. Schizophrenia patients with or without past SA either showed no significant differences, or patients with past SA showed somewhat less activation compared to patients without past SA during WM. These results suggest robust effects of past SA on WM brain functioning in controls, but less impact of past SA in schizophrenia. This is consistent with previous literature indicating less impaired neurocognition in schizophrenia with SA.

Alcohol Consumption and Executive Functions in Adolescents: A Systematic Review

Objetivo: el consumo de alcohol entre los estudiantes universitarios se ha convertido en una preocupación creciente en los últimosaños, por lo que este estudio fue desarrollado con el objetivo de identificar el consumo de esta sustancia entre los estudiantes de enfermería.Método: se trata de un estudio transversal desarrollado en una universidad privada en la ciudad de Río de Janeiro, Brasil, con 161estudiantes que respondieron a un cuestionario autoadministrado que contiene información sociodemográfica, preguntas seleccionadasdel Alcohol Use Disorders Identification Test y otros aspectos relacionados con el consumo de bebidas alcohólicas. Resultados: alta proporción(67,7 %) de los estudiantes de enfermería entrevistados reportó ser consumidores de alcohol, y el 32,1 % de ellos estaban en laorgía de consumo estándar, y casi la mitad (45,9 %) de los consumidores están expuestos al riesgo de desarrollar problemas relacionadoscon el consumo de esta sustancia. Resultados: están preocupados por el consumo de bebidas alcohólicas de los estudiantes de enfermeríaque participaron en este estudio, ya que son los futuros profesionales que inevitablemente actúan como educadores y motivadorespara la adopción de conductas saludables en la población. Conclusión: por lo tanto, se necesitan políticas y programas para prevenir elconsumo excesivo de alcohol en esta población.

Retraining the addicted brain: a review of hypothesized neurobiological mechanisms of mindfulness-based relapse prevention

Addiction has generally been characterized as a chronic relapsing condition (Leshner, 1999). Several laboratory, preclinical, and clinical studies have provided evidence that craving and negative affect are strong predictors of the relapse process. These states, as well as the desire to avoid them, have been described as primary motives for substance use. A recently developed behavioral treatment, mindfulness-based relapse prevention (MBRP), was designed to target experiences of craving and negative affect and their roles in the relapse process. MBRP offers skills in cognitive-behavioral relapse prevention integrated with mindfulness meditation. The mindfulness practices in MBRP are intended to increase discriminative awareness, with a specific focus on acceptance of uncomfortable states or challenging situations without reacting "automatically." A recent efficacy trial found that those randomized to MBRP, as compared with those in a control group, demonstrated significantly lower rates of substance use and greater decreases in craving following treatment. Furthermore, individuals in MBRP did not report increased craving or substance use in response to negative affect. It is important to note, areas of the brain that have been associated with craving, negative affect, and relapse have also been shown to be affected by mindfulness training. Drawing from the neuroimaging literature, we review several plausible mechanisms by which MBRP might be changing neural responses to the experiences of craving and negative affect, which subsequently may reduce risk for relapse. We hypothesize that MBRP may affect numerous brain systems and may reverse, repair, or compensate for the neuroadaptive changes associated with addiction and addictive-behavior relapse.

A further evaluation of decision-making under risk and under ambiguity in schizophrenia

Abnormal decision-making has been described as a key-concept to understand some behavioral disturbances in schizophrenia. However, whether schizophrenia patients display impairments in profitable decision-making on experimental designs is still controversial (1) to assess performance on decision-making paradigms under ambiguity and under risk conditions in a large sample of schizophrenia patients and (2) to study the impact of clinical variables on decision-making performance in schizophrenia. The Iowa gambling task (IGT) and the game of dice task (GDT) were administered to assess, respectively, decision-making under ambiguity and under risk in 63 schizophrenia patients and 67 healthy controls. In addition, clinical variables (e.g., schizophrenic symptoms, self-reported depression, and impulsivity) were evaluated using appropriate questionnaires the same day. Pharmacological treatments were reported. Schizophrenia patients had impaired performances on both IGT and GDT tasks. No correlation between the decision-making tasks performance and clinical variables was found. Lower gains on the GDT were associated with executive dysfunctioning in schizophrenia. These findings give evidence that schizophrenia patients display impairments in both decision-making under ambiguity and under risk.

A role for cognitive rehabilitation in increasing the effectiveness of treatment for alcohol use disorders

Neurocognitive impairments are prevalent in persons seeking treatment for alcohol use disorders (AUDs). These impairments and their physical, social, psychological and occupational consequences vary in severity across persons, much like those resulting from traumatic brain injury; however, due to their slower course of onset, alcohol-related cognitive impairments are often overlooked both within and outside of the treatment setting. Evidence suggests that cognitive impairments can impede treatment goals through their effects on treatment processes. Although some recovery of alcohol-related cognitive impairments often occurs after cessation of drinking (time-dependent recovery), the rate and extent of recovery is variable across cognitive domains and individuals. Following a long hiatus in scientific interest, a new generation of research aims to facilitate treatment process and improve AUD treatment outcomes by directly promoting cognitive recovery (experience-dependent recovery). This review updates knowledge about the nature and course of cognitive and brain impairments associated with AUD, including cognitive effects of adolescent AUD. We summarize current evidence for indirect and moderating relationships of cognitive impairment to treatment outcome, and discuss how advances in conceptual frameworks of brain-behavior relationships are fueling the development of novel AUD interventions that include techniques for cognitive remediation. Emerging evidence suggests that such interventions can be effective in promoting cognitive recovery in persons with AUD and other substance use disorders, and potentially increasing the efficacy of AUD treatments. Finally, translational approaches based on cognitive science, neurophysiology, and neuroscience research are considered as promising future directions for effective treatment development that includes cognitive rehabilitation.

Neurological function, information-motivation-behavioral skills factors, and risk behaviors among HIV-positive alcohol users

The purpose of this study was to examine neurological impairment in combination with information-motivation-behavioral skills (IMB) variables. The study tests the role of IMB variables as mediators of antecedent variables of demographics, life stress, social support, and neurological impairment with outcome measures of HIV preventive and risk behaviors in a sample of HIV-positive, alcohol-using adults (n = 250) with a history of alcohol abuse/dependence. Neurological impairment was measured with the Color Trails Test (CTT). Average performance on the CTT by the sample was substantially worse than established norms. In a directional latent variable model, neurological impairment directly predicted lower transmission knowledge scores and poorer performance on an observational condom skills assessment. Greater neurological impairment was significantly associated with greater age. Future interventions geared toward HIV+ adults who use alcohol should take into consideration HIV-related and age-related neurological functioning which may impede the facilitation of safe sex behaviors.

Guanfacine effects on stress, drug craving and prefrontal activation in cocaine dependent individuals: preliminary findings

Cocaine dependence is associated with increased stress and drug cue-induced craving and physiological arousal but decreased prefrontal activity to emotional and cognitive challenge. As these changes are associated with relapse risk, we investigated the effects of α2 receptor agonist guanfacine on these processes. Twenty-nine early abstinent treatment-seeking cocaine dependent individuals were randomly assigned to either daily placebo or guanfacine (up to 3 mg) for four weeks. In a laboratory experiment, all patients were exposed to three 10-min guided imagery conditions (stress/stress, drug cue/drug cue, stress/drug cue), one per day, consecutively in a random, counterbalanced order. Subjective craving, anxiety and arousal as well as cardiovascular output were assessed repeatedly. Brain response to stress, drug cue and relaxing imagery was also assessed during a functional magnetic resonance (fMRI) imaging session. In the current study, guanfacine was found to be safe and well-tolerated. Lower basal heart rate and blood pressure was observed in the guanfacine versus placebo group. Guanfacine lowered stress and cue-induced nicotine craving and cue-induced cocaine craving, anxiety and arousal. The guanfacine group also showed increased medial and lateral prefrontal activity following stress and drug cue exposure compared with placebo. Data suggest further exploration of guanfacine is warranted in terms of its potential for reducing stress-induced and cue-induced drug craving and arousal.

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.

Neurocognitive performance in drug-dependent males and females with posttraumatic stress disorder symptoms

Sex differences in neurobiological mechanisms of substance dependence are well documented but studies of sex differences in associated neurocognitive deficits have produced inconsistent results. Posttraumatic stress disorder (PTSD) is comorbid with substance dependence and frequently affects neurocognition. Thus, we investigated the effects of sex and PTSD symptoms on sustained attention and inhibition abilities among 126 female and 297 male substance-dependent individuals (SDIs) using the Immediate Memory Test (IMT). Females with significant PTSD (PTSD+) symptoms demonstrated significantly impaired IMT performance relative to other participants. These results represent progress in efforts to delineate sex-specific risk factors for neurocognitive deficits among SDIs.

The dynorphin/κ-opioid receptor system and its role in psychiatric disorders

The dynorphin/κ-opioid receptor system has been implicated in the pathogenesis and pathophysiology of several psychiatric disorders. In the present review, we present evidence indicating a key role for this system in modulating neurotransmission in brain circuits that subserve mood, motivation, and cognitive function. We overview the pharmacology, signaling, post-translational, post-transcriptional, transcriptional, epigenetic and cis regulation of the dynorphin/κ-opioid receptor system, and critically review functional neuroanatomical, neurochemical, and pharmacological evidence, suggesting that alterations in this system may contribute to affective disorders, drug addiction, and schizophrenia. We also overview the dynorphin/κ-opioid receptor system in the genetics of psychiatric disorders and discuss implications of the reviewed material for therapeutics development.

White matter integrity as a link in the association between motivation to abstain and treatment outcome in adolescent substance users

Readiness to change constitutes an important treatment target. This study examined white matter (WM) integrity as a possible link in the pathway between motivation to abstain and treatment outcome. Adolescents (age 14-18 years, n = 32) were recruited from intensive outpatient (IOP) substance use treatment and reported on motivation to abstain from alcohol and marijuana shortly after treatment admission (i.e., at baseline). Diffusion tensor imaging data were collected approximately 7 weeks after starting IOP and were used to quantify WM integrity (indexed by fractional anisotropy, FA) using a region of interest (ROI) approach. Treatment outcomes were assessed 6 months after baseline. Indirect effects analyses tested FA in prefrontal, orbitofrontal, and temporal ROIs as a linking variable in the pathway from motivation to abstain to alcohol and marijuana outcomes. Bivariate correlations indicated that greater motivation to abstain from alcohol was associated with lower FA in prefrontal, orbitofrontal, and temporal ROIs and that lower FA in these three ROIs was associated with greater 6-month alcohol problem severity. The indirect effect of FA was significant for the prefrontal ROI in the pathway from motivation to outcome for alcohol. FA values were not associated with motivation to abstain from marijuana or marijuana-related outcomes. Results suggest that lower WM integrity, particularly in the prefrontal brain region, may help to explain greater alcohol problem severity at 6 months despite higher motivation to abstain from alcohol. Interventions that aim to enhance WM integrity warrant attention to improve adolescent treatment outcomes.

An evidence based review of acute and long-term effects of cannabis use on executive cognitive functions

Cannabis use has been shown to impair cognitive functions on a number of levels-from basic motor coordination to more complex executive function tasks, such as the ability to plan, organize, solve problems, make decisions, remember, and control emotions and behavior. These deficits differ in severity depending on the quantity, recency, age of onset and duration of marijuana use. Understanding how cannabis use impairs executive function is important. Individuals with cannabis-related impairment in executive functions have been found to have trouble learning and applying the skills required for successful recovery, putting them at increased risk for relapse to cannabis use. Here we review the research on the acute, residual, and long-term effects of cannabis use on executive functions, and discuss the implications for treatment.

Self-regulatory processes and exercise adherence in older adults: executive function and self-efficacy effects

BACKGROUND

Self-efficacy and the use of self-regulatory strategies are consistently associated with physical activity behavior. Similarly, behavioral inhibition and cognitive resource allocation-indices of executive control function-have also been associated with this health behavior.

PURPOSE

The purpose of this study was to examine the hypothesis that self-efficacy mediates the relationship between self-regulatory processes, such as executive function, and sustained exercise behavior.

METHODS

Older adults (N=177, mean age=66.44 years) completed measures of executive function, self-reported use of self-regulatory strategies, and self-efficacy prior to and during the first month of a 12-month exercise intervention. Percentage of exercise classes attended over the following 11 months was used to represent adherence. Data were collected from 2007 to 2010 and analyzed in 2010-2011. Structural equation models were tested examining the effect of executive function and strategy use on adherence via efficacy.

RESULTS

As hypothesized, results showed significant direct effects of two elements of executive function and of strategy use on self-efficacy and of efficacy on adherence. In addition, there were significant indirect effects of strategy use and executive function on adherence via self-efficacy.

CONCLUSIONS

Higher levels of executive function and use of self-regulatory strategies at the start of an exercise program enhance beliefs in exercise capabilities, which in turn leads to greater adherence.

Neurocognitive impairment and HIV risk factors: a reciprocal relationship

Cognitive impairment among populations at risk for HIV poses a significant barrier to managing risk behaviors. The impact of HIV and several cofactors, including substance abuse and mental illness, on cognitive function is discussed in the context of HIV risk behaviors, medication adherence, and risk-reduction interventions. Literature suggests that cognitive impairment is intertwined in a close, reciprocal relationship with both risk behaviors and medication adherence. Not only do increased risk behaviors and suboptimal adherence exacerbate cognitive impairment, but cognitive impairment also reduces the effectiveness of interventions aimed at optimizing medication adherence and reducing risk. In order to be effective, risk-reduction interventions must therefore take into account the impact of cognitive impairment on learning and behavior.

Executive function and survival in the context of chronic illness

BACKGROUND

Individual differences in executive function (EF) have been shown to predict risk factors for chronic illness. It is not currently known whether EFs also predict survival time following a diagnosis of a chronic illness.

PURPOSE

The objective of this investigation was to examine the association between individual differences in EF and survival time among individuals suffering from one or more chronic illness.

METHODS

A sample of 162 community-dwelling older adults who suffered from a chronic illness at baseline underwent thorough medical and neurological examinations to ensure freedom from actual or probable dementia. Participants completed cognitive testing and were subsequently followed for 10 years; survival was assessed as survival time over the follow-up interval.

RESULTS

Findings indicated that individual differences in EF predicted survival time, and this association held when adjustments were made for demographic variables (age, sex), education, and body mass index.

CONCLUSION

Individual differences in EF may be important determinants of survival in the context of chronic illness.

Individual differences in executive functioning: implications for stress regulation

BACKGROUND

Executive functioning (EF) refers to the set of neurocognitive processes that facilitate novel problem solving, modification of behavior in response to environmental changes, planning and generating strategies for complex actions, and ability to override pre-potent behavioral and emotional responses to engage in goal-directed behavior.

PURPOSE

To provide an overview of research on individual differences in EF and examine the extent to which these individual differences confer risk and resilience for poor stress regulation.

RESULTS

Review of the literature suggests that individual differences in EF are evident at multiple levels of analysis including genotype, endophenotype (e.g., performance on cognitive tasks), and phenotype (e.g., temperament and personality). These individual differences are associated with differential stress exposure, reactivity, recovery, and restorative processes.

CONCLUSIONS

A theoretical framework that includes individual differences in EF will inform behavioral medicine research on stress risk and resilience.