A Case-Control Study of Cognitive Function in Patients with End-Stage Renal Disease Before and After Hemodialysis in Southern Spain.

BACKGROUND Cognitive problems are frequent in patients with end-stage renal disease (ESRD) treated with hemodialysis. However, previous studies used only a single cognitive screening test or a small number of cognitive indices, which is inadequate for an exhaustive evaluation of cognitive deficits. This case-control study aimed to evaluate cognitive function in patients with ESRD before and after hemodialysis at centers in southern Spain, and included analysis of associations between cognitive function and duration of hemodialysis, biochemistry, body composition, and treatment variables. MATERIAL AND METHODS Cognitive performance was evaluated in 42 healthy participants (HPs) and in 43 ESRD patients, before and after hemodialysis. The tests measured verbal and visual memory, sustained/selective attention, and processing speed. The diagnostic criterion for ESRD was a glomerular filtration rate.

Facial Emotion Recognition and Executive Functions in Fibromyalgia.

OBJECTIVE: The ability to accurately identify facial expressions of emotions is crucial in human interaction. Although a previous study suggested deficient emotional face recognition in patients with fibromyalgia, not much is known about the origin of this impairment. Against this background, the present study investigated the role of executive functions. Executive functions refer to cognitive control mechanisms enabling implementation and coordination of basic mental operations. Deficits in this domain are prevalent in fibromyalgia. METHODS: Fifty-two fibromyalgia patients and thirty-two healthy individuals completed the Ekman-60 Faces Test, which requires classification of facial displays of happiness, sadness, anger, fear, surprise, and disgust. They also completed eight tasks assessing the executive function components of shifting, updating, and inhibition. Effects of comorbid depression and anxiety disorders, as well as medication use, were tested in stratified analyses of patient subgroups. RESULTS: Patients made more errors overall than controls in classifying the emotional expressions. Moreover, their recognition accuracy correlated positively with performance on most of the executive function tasks. Emotion recognition did not vary as a function of comorbid psychiatric disorders or medication use. CONCLUSIONS: The study supports impaired facial emotion recognition in fibromyalgia, which may contribute to the interaction problems and poor social functioning characterizing this condition. Facial emotion recognition is regarded as a complex process, which may be particularly reliant on efficient coordination of various basic operations by executive functions. As such, the correlations between cognitive task performance and recognition accuracy suggest that deficits in higher cognitive functions underlie impaired emotional communication in fibromyalgia.

Factors associated with the absence of cocaine craving in treatment-seeking individuals during inpatient cocaine detoxification.

BACKGROUND: Anecdotal evidence suggests a substantial proportion of individuals with cocaine use disorder do not report craving during inpatient detoxification. OBJECTIVE: To examine prevalence and clinical correlates of consistent absence of cocaine craving among inpatients during detoxification. We hypothesized that craving absence would be associated with less severity of cocaine use, depression, and anxiety. Alternative explanations were also explored. METHODS: Craving absence (i.e., non-cravers) was defined as a daily score of zero across two separate craving visual analogue scales in each of the inpatient days. Participants scoring ≥1 on ≥1 day were considered cravers. Severity of cocaine use disorder as well as in-treatment depression and anxiety were assessed. Alternative contributors included presence of cocaine and other substances in urine at admission, in-treatment prescription of psychotropic medications, treatment motivation, executive function, interoception, and social desirability. RESULTS: Eighty-seven participants (78.2% males) met criteria as either non-cravers (n = 29; 33.3%) or cravers (n = 58; 66.7%). Mean length of admission in non-cravers and cravers was, respectively, 10.83 and 13.16 days. Binary logistic regression model showed that non-cravers scored significantly lower than cravers on cocaine use during last month before treatment (OR, 95% CI; 0.902, 0.839-0.970), in-treatment depression (OR, 95% CI; 0.794, 0.659-0.956), and in-treatment prescribing of antipsychotics (OR, 95% CI; 0.109, 0.014-0.823). Model prediction accuracy was 88.9%. CONCLUSIONS: One in three patients undergoing inpatient detoxification experienced absence of craving, linked to less pretreatment cocaine use, better mood, and decreased administration of antipsychotics. Findings may inform pretreatment strategies and improve treatment cost-effectiveness.

Impulsivity in men with prescription of benzodiazepines and methadone in prison. / Impulsividad en varones con prescripción de benzodiacepinas y metadona en prisión.

Benzodiazepines and methadone use has been associated with various neuropsychological impairments. However, to the best of our knowledge, no studies have been carried out on the effect of these substances (either separately or combined) on impulsive personality, including studies in prisoners. The aim of this study is to examine the impulsive personality of a sample of 134 male prisoners using the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (Torrubia, Avila, Molto, & Caseras, 2001) and the UPPS-P Scale (Cyders et al., 2007). Some of these were methadone users, methadone and benzodiazepines users, polydrug users in abstinence and non-dependent drug users. The results showed that drug users have greater sensitivity to reward, positive urgency, negative urgency and sensation seeking than non-dependent users. Methadone users showed more sensitivity to punishment and lack of perseverance with respect to other users. No differences were found between methadone+benzodiazepines users and other groups. The secondary aim is to examine which impulsive personality dimensions are related to the two motivational systems proposed by Gray (BIS-BAS) using exploratory factor analysis. Results showed two different components. One component was defined by the subscales sensitivity to reinforcement, positive urgency, negative urgency and sensation seeking. The second component was defined by the subscales sensitivity to punishment, lack of perseverance and lack of premeditation.

El consumo de benzodiacepinas y metadona se ha asociado a diversas alteraciones neuropsicológicas. Sin embargo, no conocemos estudios sobre el efecto de estas sustancias tanto de forma separada como de forma combinada en rasgos de personalidad impulsiva, y en menor medida  en población penitenciaria.  El objetivo principal de este estudio es examinar la impulsividad rasgo, medida con  el Cuestionario de Sensibilidad al Castigo Sensibilidad a la Recompensa (Torrubia, Avila, Moltó y Caseras, 2001), y la escala de Evaluación del Comportamiento Impulsivo UPPS-P (Cyders et al., 2007), en una muestra de 134 varones de un centro penitenciario con consumo de metadona, metadona y benzodiacepinas, abstinentes de consumo, y no dependientes del consumo de sustancias (criterios DSM-IV). Los resultados mostraron que los grupos de consumidores presentan mayor sensibilidad a la recompensa, urgencia positiva, urgencia negativa y búsqueda de sensaciones que los no consumidores; los grupos de consumo de metadona presentan mayor sensibilidad al castigo y falta de perseverancia. El grupo de  no consumidores presenta menor falta de perseverancia que el grupo de metadona y el grupo de metadona+benzodiacepinas. No se han encontrado diferencias específicamente del grupo de metadona+benzodiacepinas con el resto de los grupos. Como objetivo secundario, examinar, mediante análisis factorial exploratorio, qué dimensiones de personalidad impulsiva se relacionan con los dos sistemas motivacionales propuestos por Gray (SIC-SAC). Los resultados mostraron un componente definido por las subescalas sensibilidad al refuerzo, urgencia positiva, urgencia negativa y búsqueda de sensaciones, y un segundo definido por las subescalas sensibilidad al castigo, falta de perseverancia y falta de premeditación.

[Neuropsychological impairments in patients undergoing peritoneal dialysis treatment]. / Alteraciones neuropsicológicas en pacientes en tratamiento con diálisis peritoneal.

BACKGROUND: Patients with chronic kidney disease on hemodialysis (HD) often have cognitive deficits. However, there are few studies that have examined the neuropsychological impairments of patients receiving peritoneal dialysis (PD). METHODS: Executive functions, processing speed and verbal memory were assessed in 27 PD patients, 42 HD patients, and 42 healthy participants (HP). Systolic blood pressure and total time on renal replacement therapy (RRT) were controlled statistically. Associations between performance and clinical factors were analyzed using correlations and multiple regression. RESULTS: The DP group showed better performance compared to the HD group in verbal fluency, working memory, cognitive flexibility, planning and decision making. The DP group showed worse execution than the HP group in verbal inhibition and memory. Executive function scores were positively associated with total months on PD, total months on RRT, total months on HD, albumin, total cholesterol, and phosphorus, and negatively with ferritin. CONCLUSION: Global executive functioning was more optimal in PD patients than in HD patients. The results show the positive effect of PD on executive functions, which must be taken into account when choosing the TRS. The associations observed between biochemical factors and performance show the importance of maintaining an adequate nutritional status in these patients.

[Differential association between the regional metabolism of the prefrontal cortex and limbic structures, and the time of abstinence in substance dependent individuals]. / Asociación diferencial entre el metabolismo regional de la corteza prefrontal y las estructuras límbicas y el tiempo de abstinencia en individuos dependientes de sustancias.

Despite the existence of numerous neuroimaging studies demonstrating significant brain functional alterations in substance users, only a few studies have tried to analyze the association between the duration of abstinence and brain metabolism within substance users. The aim of this study was to examine the association between resting-state regional brain metabolism (measured with 18F-fluordeoxyglucose Positron Emission Tomography (FDGPET) and duration of drug abstinence in a sample of 49 abstinent polysubstance users. PET images were pre-processed and analyzed using SPM5 and SPSS 15. After image pre-processing, the level of glucose uptake in a pre-established set of regions of interest was extracted and bivariate correlations between this and the duration of abstinence of the participants were conducted. Results showed a negative correlation between duration of abstinence and the amygdale and the hippocampus bilaterally and a positive correlation between duration of abstinence and the left inferior frontal operculum. The associations found suggest different involvement of these structures in maintaining abstinence and emphasize the need to work on stress regulation, craving and behaviour control even after significant periods of abstinence.

Preliminary validation of the Spanish version of the Frontal Systems Behavior Scale (FrSBe) using Rasch analysis.

PRIMARY OBJECTIVE: To explore the construct validity of the Spanish version of the Frontal Systems Behavioral Scale (FrSBe) using Rasch modelling. METHODS: Item responses of 245 Spanish subjects were analysed using Rasch analysis: self-rating of 65 participants with TBI or stroke (sample A), family-rating of the same 65 participants (sample B) and self-rating of 115 healthy individuals (sample C). RESULTS: After removing or grouping several problematic items, the Apathy and the Executive Dysfunction sub-scales were found to be valid measures for samples A and B and the Disinhibition sub-scale was valid for samples B and C. Person Separation Index of reliability of sub-scales was greater than 0.83 for sample B and ∼0.72 for A and C. All items showed disordered threshold categories in samples A and B and five items were ordered in sample C. CONCLUSIONS: With a few modifications, the sub-scales of the FrSBe-Spanish version are adequate measures for the assessment of the behavioural syndromes derived from frontal systems dysfunction in persons with brain injury. The family-rating form is preferable to the self-rating form. Only the Disinhibition scale is a valid measure for the behavioural assessment of the normal population. A reduction of response categories is suggested.

[Impulsivity and compulsivity in cocaine dependent individuals]. / Impulsividad y compulsividad en individuos dependientes de cocaína.

A recent theoretical approach describes addiction as a dynamic behavioural change process on the impulsivity-compulsivity axis. However, on the basis of current evidence, it is still difficult to establish a selective association between the course of addiction and individual transition along this axis. The aim of this study is to categorize each of the individuals in a sample of cocaine-dependent patients (CDI) as mainly impulsive or mainly compulsive, on the basis of their performance in neuropsychological inhibition and perseveration tests, and to test the association between the assigned category and their scores in trait impulsivity, and severity of cocaine addiction (measured by means of self-report assessment tools). A total of 42 CDI and 65 healthy control individuals (HCI) were assessed using the UPPS-P Scale (to explore trait impulsivity), the Stroop and Go/No Go (to assess response inhibition), and Revised-Strategy Application and Probabilistic Reversal tests (to assess response perseveration). Forty-five per cent of the CDIs were classified as compulsive, and this subgroup scored significantly higher than the impulsive group on the UPPS-P dimensions of lack of perseverance and lack of premeditation. A substantial proportion of CDIs can be classified as compulsive. No differences between compulsive and impulsive CDIs were found with regard to severity of exposure to cocaine; however, patients classified as compulsive by means of neuropsychological tasks are less perseverative in the pursuit of long-term objectives and more prone to make under-meditated decisions, as shown by trait impulsivity assessment questionnaires.

Fibromyalgia Syndrome and Cognitive Decline: The Role of Body Mass Index and Clinical Symptoms.

The high prevalence of obesity and overweight in fibromyalgia (FM) may be an important factor in the well-known cognitive deficits seen in the disorder. This study analyzed the influence of body mass index (BMI) and primary clinical symptoms of FM (pain, fatigue, insomnia, anxiety, and depression) on attention, memory, and processing speed in FM. Fifty-two FM patients and thirty-two healthy participants completed cognitive tasks assessing selective, sustained, and divided attention; visuospatial and verbal memory; and information processing speed. Furthermore, they were evaluated in terms of the main clinical symptoms of the disorder. FM patients showed a marked reduction of cognitive performance in terms of selective, sustained, and divided attention; visuospatial memory; and processing speed, but no group differences were observed in verbal memory. BMI negatively affects sustained and selective attention, verbal memory, and processing speed and is the main predictor of performance in these basic cognitive domains. Our findings confirm the presence of cognitive deficits with respect to attention and visual memory, as well as slower processing speed, in FM. Moreover, the results support a role of BMI in the observed cognitive deficits. Interventions increasing physical activity and promoting cognitive stimulation could be useful for strengthening cognitive function in FM patients.

A transdiagnostic dimensional approach towards a neuropsychological assessment for addiction: an international Delphi consensus study.

BACKGROUND: The US National Institutes of Mental Health Research Domain Criteria (RDoC) seek to stimulate research into biologically validated neuropsychological dimensions across mental illness symptoms and diagnoses. The RDoC framework comprises 39 functional constructs designed to be revised and refined, with the overall goal of improving diagnostic validity and treatments. This study aimed to reach a consensus among experts in the addiction field on the 'primary' RDoC constructs most relevant to substance and behavioural addictions. METHODS: Forty-four addiction experts were recruited from Australia, Asia, Europe and the Americas. The Delphi technique was used to determine a consensus as to the degree of importance of each construct in understanding the essential dimensions underpinning addictive behaviours. Expert opinions were canvassed online over three rounds (97% completion rate), with each consecutive round offering feedback for experts to review their opinions. RESULTS: Seven constructs were endorsed by ≥ 80% of experts as 'primary' to the understanding of addictive behaviour: five from the Positive Valence System (reward valuation, expectancy, action selection, reward learning, habit); one from the Cognitive Control System (response selection/inhibition); and one expert-initiated construct (compulsivity). These constructs were rated to be related differentially to stages of the addiction cycle, with some linked more closely to addiction onset and others more to chronicity. Experts agreed that these neuropsychological dimensions apply across a range of addictions. CONCLUSIONS: The study offers a novel and neuropsychologically informed theoretical framework, as well as a cogent step forward to test transdiagnostic concepts in addiction research, with direct implications for assessment, diagnosis, staging of disorder, and treatment.

Risky decision-making after exposure to a food-choice task in excess weight adolescents: Relationships with reward-related impulsivity and hunger.

OBJECTIVE: To assess the effects of exposure to a food-choice task (appetizing versus healthy food) on risky decision-making by excess versus normal weight adolescents. We also analyzed the influence of food visualization on hunger levels, as well as group differences in food choices and impulsivity. METHODS: Fifty-six adolescents (aged 13-18 years) classified as excess (n = 27) or normal (n = 29) weight participated in the study. Risky-decision-making was assessed through the Balloon Analogue Risk Task, which was administered before and after a food-choice task. We also evaluated impulsivity traits through the UPPS-P Scale, and subjective hunger levels with a visual analogue scale. RESULTS: Adolescents with excess weight showed enhanced risky decision-making after the food-choice task compared to normal weight adolescents, as well as increased hunger levels. Furthermore, excess weight adolescents made more appetizing choices, and showed greater scores for Positive Urgency and Sensation Seeking. Reward-related impulsivity measures were positively associated with the number of appetizing choices in the food-choice task. Several associations were found between impulsivity measures, hunger levels and risk-taking variables. CONCLUSIONS: Excess weight adolescents increased their risky-decision-making after food exposure and this augmentation was associated with the increase in hunger levels. Increased hunger levels and risk-taking after food exposure could lead to overeating. Alterations in decision-making caused by food signals may be a long-term risk factor for the development of obesity in adulthood. In modern societies, with the high availability and continuous exposure to food cues, decision-making may be a crucial factor in maintain healthy eating habits in adolescents.

Executive function in end-stage renal disease: Acute effects of hemodialysis and associations with clinical factors.

OBJECTIVE: There is evidence of cognitive impairment in patients with end-stage renal disease in hemodialysis (ESRD-HD). However, few studies have exhaustively analyzed executive functions (EFs) in this population, especially considering the influence of a wide range of clinical variables. This study analyzes performance in different EF components in ESRD-HD patients compared to a group of healthy controls (HCs), in addition to the acute effects of HD and the associations of cognitive performance with clinical variables. METHOD: EFs were evaluated pre- and post-HD in 43 ESRD-HD patients and 42 HCs, using a battery of tests designed to assess EF domains. Age, schooling, mood and blood pressure were statistically controlled. Associations between performance and clinical factors were computed by correlations and hierarchical multiple regression analyses. RESULTS: The performance of the ESRD-HD patients was significantly lower than that of HCs in all the EF domains except for planning. Group differences were marginally significant for reasoning. HD produced no acute changes in global performance, with improvements see only in inhibition and working memory. EF scores were positively associated with total number of months previously transplanted, body mass index (BMI), dry weight, and levels of hemoglobin, albumin, ferritin, calcium, phosphorus, sodium, urea, and creatinine. CONCLUSIONS: Global EF functioning was lower in ESRD-HD patients than in HCs. No major acute HD-related EF changes were detected. These findings underline the importance of an adequate nutritional status for maintaining executive functioning in ESRD-HD patients.

Executive function impairments in fibromyalgia syndrome: Relevance of clinical variables and body mass index.

BACKGROUND: Several investigations suggest the presence of deterioration of executive function in fibromyalgia syndrome (FMS). The study quantified executive functions in patients with FMS. A wide array of functions was assessed, including updating, shifting and inhibition, as well as decision making and mental planning. Moreover, clinical variables were investigated as possible mediators of executive dysfunction, including pain severity, psychiatric comorbidity, medication and body mass index (BMI). METHODS: Fifty-two FMS patients and 32 healthy controls completed a battery of 14 neuropsychological tests. Clinical interviews were conducted and the McGill Pain Questionnaire, Beck Depression Inventory, State-Trait Anxiety Inventory, Fatigue Severity Scale and Oviedo Quality of Sleep Questionnaire were presented. RESULTS: Patients performed poorer than controls on the Letter Number Sequencing, Arithmetic and Similarities subtests of the Wechsler Adult Intelligence Scale, the Spatial Span subtest of the Wechsler Memory Scale, an N-back task, a verbal fluency task, the Ruff Figural Fluency Test, the Inhibition score of the Stroop Test, the Inhibition and Shifting scores of the Five Digits Test, the Key Search Test and the Zoo Map Task. Moreover, patients exhibited less steep learning curves on the Iowa Gambling Task. Among clinical variables, BMI and pain severity explained the largest proportion of performance variance. CONCLUSIONS: This study demonstrated impairments in executive functions of updating, shifting inhibition, decision making and planning in FMS. While the mediating role of pain in cognitive impairments in FMS had been previously established, the influence of BMI is a novel finding. Overweight and obesity should be considered by FMS researchers, and in the treatment of the condition.

Cognitive deficits in fibromyalgia syndrome are associated with pain responses to low intensity pressure stimulation.

BACKGROUND: Fibromyalgia syndrome (FMS) is a chronic disorder characterized by widespread musculoskeletal pain and diffuse tenderness, accompanied by complaints including morning stiffness, fatigue, insomnia and affective symptoms. In addition, affected patients frequently experience cognitive impairments such as concentration difficulties, forgetfulness or problems in planning and decision-making. These deficits are commonly ascribed to interference between nociceptive and cognitive processing. METHOD: The present study investigated the association of cognitive performance with (a) pain responses to low intensity pressure stimulation (0.45-2.25 kg/cm2), (b) responses to stronger (above-threshold) stimulation (2.70 kg/cm2), and (c) pain threshold and tolerance in 42 women with FMS. Tests of attention, memory, processing speed, and executive functions were applied. RESULTS: While no significant correlations were seen for pain threshold and pain tolerance, inverse associations arose between pain intensity ratings during pressure stimulation and performance in all evaluated cognitive domains. The magnitude of the correlations increased with decreasing stimulus intensity. CONCLUSIONS: It may be concluded that pain experience during somatosensory stimulation of low intensity is more closely related to attention, memory and executive functions in FMS than the traditional measures of pain threshold and pain tolerance. Considering that pain responses to low intensity stimulation reflect the hyperalgesia and allodynia phenomena characterizing FMS, it may be hypothesized that central nervous pain sensitization is involved in cognitive impairments in the disorder.

Aberrant cerebral blood flow responses during cognition: Implications for the understanding of cognitive deficits in fibromyalgia.

OBJECTIVE: There is ample evidence for cognitive deficits in fibromyalgia syndrome (FMS). The present study investigated cerebral blood flow responses during arithmetic processing in FMS patients and its relationship with performance. The influence of clinical factors on performance and blood flow responses were also analyzed. METHOD: Forty-five FMS patients and 32 matched healthy controls completed a mental arithmetic task while cerebral blood flow velocities in the middle (MCA) and anterior (ACA) cerebral arteries were measured bilaterally using functional transcranial Doppler sonography (fTCD). RESULTS: Patients' cognitive processing speeds were slower versus healthy controls. In contrast to patients, healthy controls showed a pronounced early blood flow response (during seconds 4-6 after the warning signal) in all assessed arteries. MCA blood flow modulation during this period was correlated with task performance. This early blood flow response component was markedly less pronounced in FMS patients in both MCAs. Furthermore, patients displayed an aberrant pattern of lateralization, with right hemispheric dominance especially observed in the ACA. Severity of clinical pain in FMS patients was correlated with cognitive performance and cerebral blood flow responses. CONCLUSIONS: Cognitive impairment in FMS is associated with alterations in cerebral blood flow responses during cognitive processing. These results suggest a potential physiological pathway through which psychosocial and clinical factors may affect cognition.

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.

Neural correlates of hot and cold executive functions in polysubstance addiction: association between neuropsychological performance and resting brain metabolism as measured by positron emission tomography.

The study of substance-abuse-related neuropsychological deficits and brain alterations may provide a better understanding of the neuroadaptations associated with addiction. In this study we investigated the association between performance on neuropsychological tests of cold and hot executive functions and regional brain metabolism. Measured with positron emission tomography (PET), in a sample of 49 substance-dependent individuals (SDI). Neuropsychological performance in the SDI group was compared to that of a non-drug-using control group of 30 participants, and associated with two sets of PET-derived dependent measures: one based on regions of interest (examining mean uptake in selected regions), and a second based on voxel uptake measures (using Statistical Parametric Mapping voxel-based whole-brain analyses). Behavioral analyses showed that SDI had poorer performance than controls across executive function and emotion processing measures. Regression models showed that SDI's performance in "cold" executive tests (i.e., updating, inhibition and flexibility) was associated with regional metabolism in the dorsolateral prefrontal cortex (DLPFC), mid-superior frontal gyrus, superior and inferior temporal gyrus and inferior parietal cortex, whereas performance in "hot" executive functions (i.e., self-regulation, decision-making and emotion perception) was associated with DLPFC, mid-superior frontal gyrus, anterior and mid-posterior cingulate, and temporal and fusiform gyrus. These results are discussed in terms of their relevance for the understanding of cognitive dysfunction and neuroadaptations linked to addiction.

Trait impulsivity and prefrontal gray matter reductions in cocaine dependent individuals.

BACKGROUND: Impulsivity is thought to play a key role in cocaine addiction onset and progression; therefore, we hypothesized that different facets of impulsive personality may be significantly associated with brain structural abnormalities in cocaine-dependent individuals. METHODS: Thirty-eight cocaine-dependent individuals and 38 non-drug using controls completed the UPPS-P scale (measuring five different facets of impulsivity: sensation seeking, lack of premeditation, lack of perseverance, and positive and negative urgency) and were scanned on a 3T MRI scanner. We used whole-brain voxel-based morphometry analyses (VBM) to detect differences in gray matter (GM) and white matter (WM) volumes between cocaine users and controls, and to measure differences in the way that impulsivity relates to GM and WM volumes in cocaine users vs. controls. RESULTS: Cocaine-dependent individuals had lower GM volumes in a number of sections of the orbitofrontal cortex, right inferior frontal gyrus, right insula, left amygdala and parahippocampal gyrus, temporal gyrus, and bilateral caudate. They also had lower WM volumes in the left inferior and medial frontal gyrus, superior temporal gyrus, right anterior cingulate cortex, insula and caudate. There was a positive correlation between trait impulsivity and GM volume in the left inferior/middle frontal gyrus of cocaine-dependent individuals, a pattern directly opposed to the association in controls. Conversely, in cocaine users lack of premeditation was negatively correlated with GM volume in the insula and the putamen. CONCLUSIONS: Trait impulsivity may influence cocaine dependence by impacting its neurobiological underpinnings in frontostriatal systems.

Neural correlates of the severity of cocaine, heroin, alcohol, MDMA and cannabis use in polysubstance abusers: a resting-PET brain metabolism study.

INTRODUCTION: Functional imaging studies of addiction following protracted abstinence have not been systematically conducted to look at the associations between severity of use of different drugs and brain dysfunction. Findings from such studies may be relevant to implement specific interventions for treatment. The aim of this study was to examine the association between resting-state regional brain metabolism (measured with 18F-fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and the severity of use of cocaine, heroin, alcohol, MDMA and cannabis in a sample of polysubstance users with prolonged abstinence from all drugs used. METHODS: Our sample consisted of 49 polysubstance users enrolled in residential treatment. We conducted correlation analyses between estimates of use of cocaine, heroin, alcohol, MDMA and cannabis and brain metabolism (BM) (using Statistical Parametric Mapping voxel-based (VB) whole-brain analyses). In all correlation analyses conducted for each of the drugs we controlled for the co-abuse of the other drugs used. RESULTS: The analysis showed significant negative correlations between severity of heroin, alcohol, MDMA and cannabis use and BM in the dorsolateral prefrontal cortex (DLPFC) and temporal cortex. Alcohol use was further associated with lower metabolism in frontal premotor cortex and putamen, and stimulants use with parietal cortex. CONCLUSIONS: Duration of use of different drugs negatively correlated with overlapping regions in the DLPFC, whereas severity of cocaine, heroin and alcohol use selectively impact parietal, temporal, and frontal-premotor/basal ganglia regions respectively. The knowledge of these associations could be useful in the clinical practice since different brain alterations have been associated with different patterns of execution that may affect the rehabilitation of these patients.

What are the specific vs. generalized effects of drugs of abuse on neuropsychological performance?

Most substance abusers simultaneously use and abuse more than one substance, even when there is a clear drug of choice. This pattern creates a great challenge in relating neuropsychological findings in drug users to a certain drug. This review aims to: (i) discuss results from neuropsychological studies using different research methodologies that may improve our understanding of specific vs. generalized effects of different drugs on neuropsychological performance; and (ii) determine which neuropsychological mechanisms are impaired in the same way by the use of different drugs, and which impairments are specific to certain substances, including cannabis, psychostimulants, opioids and alcohol. We review evidence from human studies in chronic substance abusers using three methodologies: (i) studies on 'pure' users of one particular substance, (ii) studies that methodologically control the effects of drugs co-abused, and (iii) studies contrasting subgroups of polysubstance users with different drugs of choice. Converging evidence from these approaches indicates that all the drugs studied are commonly associated with significant alterations in the neuropsychological domains of episodic memory, emotional processing, and the executive components of updating and decision-making. However, there is evidence of a greater reliability in the association of certain substances with specific neuropsychological domains. Specifically, there are relatively more robust effects of psychostimulants and alcohol use on impulsive action and cognitive flexibility, of alcohol and MDMA use on spatial processing, perceptual speed and selective attention, cannabis and methamphetamine on prospective memory deficits, and cannabis and MDMA on processing speed and complex planning. The magnitude of both generalized and specific neuropsychological effects is overall attenuated in samples achieving long-term abstinence, but there are persistent psychostimulant-related effects on updating, inhibition, flexibility and emotional processing, and opioid-related effects on updating and decision-making.