Trait impulsivity is related to ventral ACC and amygdala activity during primary reward anticipation

Trait impulsivity is characterized by behavioral disinhibition and rash decision-making that contribute to many maladaptive behaviors. Previous research demonstrates that trait impulsivity is related to the activity of brain regions underlying reward sensitivity and emotion regulation, but little is known about this relationship in the context of immediately available primary reward. This is unfortunate, as impulsivity in these contexts can lead to unhealthy behaviors, including poor food choices, dangerous drug use and risky sexual practices. In addition, little is known about the relationship between integration of reward and affective neurocircuitry, as measured by resting-state functional connectivity, and trait impulsivity in everyday life, as measured with a commonly used personality inventory. We therefore asked healthy adults to undergo a functional magnetic resonance imaging task in which they saw cues indicating the imminent oral administration of rewarding taste, as well as a resting-state scan. Trait impulsivity was associated with increased activation during anticipation of primary reward in the anterior cingulate cortex (ACC) and amygdala. Additionally, resting-state functional connectivity between the ACC and the right amygdala was negatively correlated with trait impulsivity. These findings demonstrate that trait impulsivity is related not only to ACC-amygdala activation but also to how tightly coupled these regions are to one another.     

Personality traits as prospective predictors of suicide attempts

Objective: To examine higher order personality factors of negative affectivity (NA) and disinhibition (DIS), as well as lower order facets of impulsivity, as prospective predictors of suicide attempts in a predominantly personality disordered sample. Method: Data were analyzed from 701 participants of the Collaborative Longitudinal Personality Disorders Study with available follow‐up data for up to 7 years. Cox proportional hazards regression analyses was used to examine NA and DIS, and facets of impulsivity (e.g. urgency, lack of perseverance, lack of premeditation and sensation seeking), as prospective predictors of suicide attempts. Results: NA, DIS and all facets of impulsivity except for sensation seeking were significant in univariate analyses. In multivariate models which included sex, childhood sexual abuse, course of major depressive disorder and substance use disorders, only NA and lack of premeditation remained significant in predicting suicide attempts. DIS and the remaining impulsivity facets were not significant. Conclusion: NA emerged as a stronger and more robust predictor of suicide attempts than DIS and impulsivity, and warrants greater attention in suicide risk assessment. Distinguishing between facets of impulsivity is important for clinical risk assessment.     

Activity-specific pathways among duration of organized activity involvement,social support,and adolescent well-being: Findings from a nationally representative sample

Using data from N = 10,148 American youth (M_age = 15.18) who participated in the National Comorbidity Survey Adolescent Supplement, we tested whether duration of involvement in specific organized activities was associated with different sources of social support, and whether these links explained the health-related benefits affiliated with participation. Duration of involvement in certain activities was differentially associated with support from peers, teachers, and other adults, and many of these links partially mediated associations between involvement and well-being. Specifically, greater duration of sports involvement was indirectly associated with higher self-esteem and greater physical activity through greater adult support. Greater duration of club involvement was indirectly associated with greater physical activity through higher adult support and greater duration of music involvement was indirectly associated with lower substance use and greater self-esteem through greater teacher support. Prolonged engagement in specific activities may cultivate certain types of supportive relationships, which may promote adolescent well-being.     

The effect of 5-HTT gene promoter polymorphism on impulsivity depends on family relations in girls

The short (S) allele of the 5-HTT gene promoter region polymorphism (5-HTTLPR), in combination with adverse environmental influence, leads to higher likelihood of depression. Impulsivity has been related to low serotonin turnover, poor regulation of affect, and problems in the family, including child maltreatment. The current study explored the effect of the 5-HTTLPR polymorphism in the serotonin transporter gene and adverse family environment on impulsivity in adolescents. Healthy adolescents participating in the Estonian Children Personality Behaviour and Health Study (n=483) filled the Adaptive and Maladaptive Impulsivity Scale (AMIS), Barratt Impulsiveness Scale (BIS-11), a scale measuring family relations, and were genotyped. While genotype alone was not associated with thoughtlessness, BIS-11 impulsiveness, fast decision-making or excitement seeking, 5-HTTLPR S allele carriers, however, had higher scores of disinhibition. In girls carrying the S allele, scores of thoughtlessness and disinhibition depended on family relations, being higher with less warmth in the family. Adverse family relations had no effect on impulsivity in girls with LL genotype. In boys, the effects of family relations on maladaptive impulsivity did not depend on genotype. However, the S allele and high maltreatment in the family both independently increased disinhibition and the BIS-11 score in boys. Family environment and the 5-HTTLPR genotype had no interactive effect on excitement seeking or fast decision-making. In summary, carrying the S allele may lead to high maladaptive impulsivity due to higher sensitivity to environmental adversity, which is more significantly expressed in girls.     

Childhood trauma,dimensions of psychopathology and the clinical expression of bipolar disorders: A pathway analysis

BackgroundThis study aims at testing for paths from childhood abuse to clinical indicators of complexity in bipolar disorder (BD), through dimensions of affective dysregulation, impulsivity and hostility.Method485 euthymic patients with BD from the FACE-BD cohort were included from 2009 to 2014. We collect clinical indicators of complexity/severity: age and polarity at onset, suicide attempt, rapid cycling and substance misuse. Patients completed questionnaires to assess childhood emotional, sexual and physical abuses, affective lability, affect intensity, impulsivity, motor and attitudinal hostility.ResultsThe path-analysis demonstrated significant associations between emotional abuse and all the affective/impulsive dimensions (p < 0.001). Sexual abuse was moderately associated with emotion-related dimensions but not with impulsivity nor motor hostility. In turn, affect intensity and attitudinal hostility were associated with high risk for lifetime presence of suicide attempts (p < 0.001), whereas impulsivity was associated with a higher risk of lifetime presence of substance misuse (p < 0.001). No major additional paths were identified when including Emotional and Physical Neglect in the model.ConclusionsThis study provides refinement of the links between early adversity, dimensions of psychopathology and the complexity/severity of BD. Mainly, dimensions of affective dysregulation, impulsivity/hostility partially mediate the links between childhood emotional to suicide attempts and substance misuse in BD.     

Emotionally laden impulsivity interacts with affect in predicting addictive use of online sexual activity in men

The interest in studying addictive use of online sexual activities (OSA) has grown sharply over the last decade. Despite the burgeoning number of studies conceptualizing the excessive use of OSA as an addictive disorder, few have tested its relations to impulsivity, which is known to constitute a hallmark of addictive behaviors. To address this missing gap in the literature, we tested the relationships between addictive OSA use, impulsivity traits, and affect among a convenience sample of men (N = 182; age, M = 29.17, SD = 9.34), building upon a theoretically driven model that distinguishes the various facets of impulsivity. Results showed that negative urgency (an impulsivity trait reflecting the tendency to act rashly in negative emotional states) and negative affect interact in predicting addictive OSA use. These results highlight the pivotal role played by negative urgency and negative affect in addictive OSA use, supporting the relevance of psychological interventions that focus on improving emotional regulation (e.g., to reduce negative affect and learn healthier coping strategies) to mitigate excessive use of OSA.     

Executive cognitive functions and impulsivity as correlates of risk taking and problem behavior in preadolescents

Initiation of drug use and other risky behavior in preadolescence is associated with poor developmental outcomes. In this research, we examine models that ascribe the trajectory to (a) weak executive cognitive function (ECF), (b) early manifestation of externalizing problems, or (c) heightened levels of trait impulsivity. We test the explanatory power of these factors in a structural equation model with a community sample of 387 preadolescents ages 10–12 years. Participants were tested with a computerized battery of tasks to assess three facets of ECF (working memory, cognitive control, and reward processing) as well as with an audio assisted computerized self-interview to obtain reports of impulsivity and risk behaviors (use of cigarettes and alcohol as well as engaging in fighting and gambling for money) and a self-administered questionnaire to assess externalizing and internalizing problems. The best fitting model explained both early risk taking and externalizing symptoms as the result of individual differences in impulsivity. Although no ECF was directly related to risk taking, working memory and one measure of reward processing performance (reversal learning) were inversely related to impulsivity. The results are discussed in regard to theories of early risk taking with particular focus on the potential relation between ECF and impulsive behavior tendencies and the implications for early intervention to prevent the dysfunctional trajectory associated with early risk behavior.     

Parental inconsistency,impulsive choice and neural value representations in healthy adolescents

A well-characterized potential marker for addiction is impulsive choice, stably measured by delay discounting (DD) paradigms. While genetic influences partly account for inter-individual variance in impulsivity, environmental factors such as parenting practices may have an important role. The present study investigates how inconsistent fulfillment of delayed reward promises impacts on DD. A combined correlational and experimental functional magnetic resonance imaging (fMRI) design was performed in a sample of 48 healthy adolescents (13–15 years). More specifically, neural activation during a DD task was investigated at two assessment points (T₀ and T₁). Adolescents'' self-reports of parenting and substance use were assessed at T₀. Between assessment points, we experimentally varied the reliability of delayed reward promises, measuring the impact of this intervention on DD and neural value processing at T₁. In the correlational part, same-sex parent reward inconsistency was associated with steeper DD and an attenuated subjective value (SV) representation in the nucleus accumbens (NAcc) and ventromedial prefrontal cortex (vmPFC). Steeper DD was in turn associated with alcohol use during the past year. In the experimental part, the reward inconsistency manipulation resulted in an attenuation of the NAcc SV representation, similar to the parental inconsistency effect. Together, our correlational and experimental findings raise new light on how parents may influence their children''s degree of impulsivity, making parenting a potential target in addiction prevention.     

Sustained Impact of Inattention and Hyperactivity-Impulsivity on Peer Problems: Mediating Roles of Prosocial Skills and Conduct Problems in a Community Sample of Children

This prospective 2-year longitudinal study tested whether inattentive and hyperactive/impulsive symptom dimensions predicted future peer problems, when accounting for concurrent conduct problems and prosocial skills. A community sample of 492 children (49 % female) who ranged in age from 6 to 10 years (M = 8.6, SD = .93) was recruited. Teacher reports of children’s inattention, and hyperactivity/impulsivity symptoms, conduct problems, prosocial skills and peer problems were collected in two consecutive school years. Elevated inattention and hyperactivity/impulsivity in Year-1 predicted greater peer problems in Year-2. Conduct problems in the first and second years of the study were associated with more peer problems, and explained a portion of the relationship between inattention and hyperactivity/impulsivity with peer problems. However, prosocial skills were associated with fewer peer problems in children with elevated inattention and hyperactivity/impulsivity. Inattention and hyperactivity/impulsivity have negative effects on children’s peer functioning after 1-year, but concurrent conduct problems and prosocial skills have important and opposing impacts on these associations.     

Hoarding and the multi-faceted construct of impulsivity: A cross-cultural investigation

The proposed hoarding disorder represents a serious psychiatric condition and considerable public health burden. Although tremendous strides have been made in understanding the phenomenology and treatment of this condition, many features regarding the etiology and nosology remain unclear. In particular, the association between impulsivity and hoarding, as well as the differential role of impulsivity versus compulsivity has yet to be fully considered. The current investigation sought to fill this gap in the literature by examining the relationship between hoarding and impulsivity across two independent, cross-cultural investigations. Two separate conceptualizations of the impulsivity construct were considered, including the Barratt Impulsivity Scale and the UPPS Impulsive Behavior Scale. Across Study 1 (US young adult sample; N = 372) and Study 2 (German young adult sample; N = 160) results revealed that hoarding was associated with greater rates of impulsivity, despite controlling for theoretically relevant covariates. More fined-grained analyses revealed a differential relationship with respect to the various facets of impulsivity, such that hoarding was most strongly linked with attentional and motor impulsivity, as well as urgency (i.e., impulsive behaviors in response to negative affect) and lack of perseverance. When considered simultaneously, both impulsivity and non-hoarding OCD symptoms explained unique variance in hoarding. The implications of impulsivity for hoarding are discussed from a classification perspective, as well as from a vulnerability standpoint.     

Prospective effects of attention-deficit/hyperactivity disorder, conduct disorder, and sex on adolescent substance use and abuse

CONTEXT: Attention-deficit/hyperactivity disorder (ADHD), an early manifestation of externalizing behavior, may identify children at high risk for later substance abuse. However, the ADHD-substance abuse relationship often disappears when co-occurring conduct disorder (CD) is considered. OBJECTIVE: To determine whether there is a prospective relationship between ADHD and the initiation of substance use and disorders, and whether this relationship depends on the ADHD subtype (hyperactive/impulsive or inattentive), CD, or sex. DESIGN, SETTING, AND PARTICIPANTS: Dimensional and categorical measures of ADHD and CD were examined via logistic regression analyses in relation to subsequent initiation of tobacco, alcohol, and illicit drug use by 14 years of age and onset of substance use disorders by 18 years of age in a population-based sample of 11-year-old twins (760 female and 752 male twins) from the Minnesota Twin Family Study. MAIN OUTCOME MEASURES: Structured interviews were administered to adolescents and their mothers regarding substance use and to generate diagnoses. RESULTS: For boys and girls, hyperactivity/impulsivity predicted initiation of all types of substance use, nicotine dependence, and cannabis abuse/dependence (for all, P < .05), even when controlling for CD at 2 time points. By contrast, relationships between inattention and substance outcomes disappeared when hyperactivity/impulsivity and CD were controlled for, with the possible exception of nicotine dependence. A categorical diagnosis of ADHD significantly predicted tobacco and illicit drug use only (adjusted odds ratios, 2.01 and 2.82, respectively). A diagnosis of CD between 11 and 14 years of age was a powerful predictor of substance disorders by 18 years of age (all odds ratios, > 4.27). CONCLUSIONS: Hyperactivity/impulsivity predicts later substance problems, even after growth in later-emerging CD is considered, whereas inattention alone poses less risk. Even a single symptom of ADHD or CD is associated with increased risk. Failure in previous research to consistently observe relationships between ADHD and substance use and abuse outcomes could be due to reliance on less-sensitive categorical diagnoses.     

Commercial Facilities,Social Cognitive Variables,and Physical Activity of 12th Grade Girls

Background  Recent studies have found a relationship between access to neighborhood physical activity (PA) facilities and physical activity in youth. Purpose  The purpose of this study was to assess whether proximity of commercial PA facilities was related to vigorous physical activity (VPA) in 12th grade girls, independent of sport participation and social-cognitive influences, including perceived features of the social and physical environment. Methods  Girls (N = 1,126 girls; 55% black, body mass index = 25.0 ± 6.4) in 22 high schools completed questionnaires and provided home addresses. Using geographic information systems technology, commercial PA facilities were mapped and counted within 0.75- and 2.0-mile street network buffers around each girl’s home. Girls self-reported PA using the 3-day physical activity recall. Results  Approximately 25% of girls had at least one PA facility within the 0.75-mile buffer, and 65% of girls had at least one PA facility within the 2.0-mile buffer. Models of the direct and indirect relations of commercial PA facilities at 0.75- and 2.0-mile buffers, sport participation, self-efficacy for overcoming barriers and perceived physical and social environment with VPA both had acceptable fit to data (root mean square error of approximation = 0.049 and comparative fit index = 0.91). Conclusions  The results indicate that proximity to multipurpose commercial PA facilities is a correlate of VPA independent of sport participation and perceived features of the social and physical environment.     

Delay discounting and neurocognitive correlates among inner city adolescents with and without family history of substance use disorder

Adolescents with a family history (FH+) of substance use disorder (SUD) are at a greater risk for SUD, suggested to be partly due to the transmission of behavioral impulsivity. We used a delay discounting task to compare impulsivity in decision-making and its associated brain functioning among FH+ and FH - minority adolescents. Participants chose between Smaller Sooner (SS) and Larger Later (LL) rewards. The SS was available immediately (Now trials) or in the future (Not-Now trials), allowing for greater differentiation between impulsive decisions. The FH+ group showed greater impatience by responding SS more frequently than the FH - group, only on the Now trials, and even when the relative reward differences (RRD) increased. Surprisingly, there were no differences in brain activity between the groups. Combined, the groups showed greater reward activity during the Now vs. Not-Now trials in medial prefrontal/anterior cingulate, posterior cingulate, precuneus, and inferior frontal gyrus (i.e., an immediacy effect). As the RRD increased activation in the reward network decreased, including the striatum, possibly reflecting easy decision-making. These results indicate that risk for SUD, seen behaviorally among FH+ adolescents, may not yet be associated with discernable brain changes, suggesting that early intervention has the potential to reduce this risk.     

Attentional and motor impulsivity interactively predict ‘food addiction’ in obese individuals

BackgroundImpulsivity is a multifaceted construct and constitutes a common risk factor for a range of behaviors associated with poor self-control (e.g., substance use or binge eating). The short form of the Barratt Impulsiveness Scale (BIS-15) measures impulsive behaviors related to attentional (inability to focus attention or concentrate), motor (acting without thinking), and non-planning (lack of future orientation or forethought) impulsivity. Eating-related measures appear to be particularly related to attentional and motor impulsivity and recent findings suggest that interactive effects between these two facets may play a role in eating- and weight-regulation.MethodsOne-hundred thirty-three obese individuals presenting for bariatric surgery (77.4% female) completed the BIS-15 and the Yale Food Addiction Scale (YFAS) 2.0, which measures addiction-like eating based on the eleven symptoms of substance use disorder outlined in the fifth version of the Diagnostic and Statistical Manual of Mental Disorders.ResultsSixty-three participants (47.4%) were classified as being ‘food addicted’. Scores on attentional and motor impulsivity interactively predicted ‘food addiction’ status: higher attentional impulsivity was associated with a higher likelihood of receiving a YFAS 2.0 diagnosis only at high (+1 SD), but not at low (−1 SD) levels of motor impulsivity.ConclusionsResults support previous findings showing that non-planning impulsivity does not appear to play a role in eating-related self-regulation. Furthermore, this is the first study that shows interactive effects between different impulsivity facets when predicting ‘food addiction’ in obese individuals. Self-regulatory failure in eating-regulation (e.g., addiction-like overeating) may particularly emerge when both attentional and motor impulsivity levels are elevated.     

Are ADHD Symptoms Associated With Delay Aversion or Choice Impulsivity? A General Population Study

ObjectiveThe term delay aversion has been used both to describe a behavioral tendency of greater preference for smaller-immediate over larger-delayed rewards (choice impulsivity) and to refer to a secondary explanatory construct put forward by delay aversion theory. In this study, we examined the association of attention-deficit/hyperactivity disorder (ADHD) symptoms with choice impulsivity and tested the specific hypothesis derived from delay aversion theory.MethodA total of 1,062 children aged 7.90 to 10.90 years (49% girls) made a fixed number of repeated choices between a smaller reward delivered immediately and a larger reward delivered after a delay (choice-delay task), under two conditions (including and excluding a postreward delay). We assessed the unique contribution of each ADHD symptom dimension to the prediction of choice impulsivity and delay aversion, controlling for age (or age and IQ). Sex effects were examined.ResultsInattention ratings uniquely predicted preference for smaller-immediate rewards under both task conditions for both sexes. An index of delay aversion was associated with inattention only in boys; the effect size was small yet significant. Hyperactivity-impulsivity ratings were negatively associated with choice impulsivity in girls in the postreward delay condition, whereas no significant association with hyperactivity-impulsivity ratings was observed in boys. Categorical analyses using groups with high ADHD symptoms yielded similar results.ConclusionsThis is the first study to report a unique association between inattention symptoms and behavioral measures of choice impulsivity and delay aversion. The findings indicate the importance of the primary constitutional processes that underlie choice impulsivity and their potential role in behavioral inattention. Understanding the behavioral and brain processes underlying choice impulsivity may lead to the improved targeting of behavioral and pharmacological interventions.     

Deep brain stimulation effect on anterior pallidum reduces motor impulsivity in Parkinson's disease

BackgroundDeep Brain Stimulation (DBS) of the subthalamic nucleus or globus pallidus internus is used to treat the motor symptoms of Parkinson's disease. The former can worsen impulsive and compulsive behaviors after controlling for the reduction of dopaminergic medications. However, the effect of pallidal DBS on such behaviors in PD patients is less clear.Objective/Hypothesis: We hypothesized that greater stimulation spread to the pallidum with prefrontal connectivity would reduce motor impulsivity.MethodsSeven Parkinson's patients with stable globus pallidus internus DBS settings for 3 months, disease duration of 13 ± 1.3 years, and Montreal Cognitive Assessment of 26.8 ± 1.1 each had two stimulation settings defined based on reconstructions of lead placement and volume of tissue activation targeting either a dorsal or ventral position along the DBS electrode but still within the globus pallidus internus. Subjects performed a stop signal reaction time task with the DBS turned off vs. on in each of the defined stimulation settings, which was correlated with the degree of stimulation effect on pallidal subregions.ResultsA shorter distance between the volume of tissue activation and the right prefrontally-connected GPi correlated with less impulsivity on the stop signal reaction time task (r = 0.69, p < 0.05). Greater volume of tissue activation overlap with the non-prefrontally-connected globus pallidus internus was associated with increased impulsivity.ConclusionThese data can be leveraged to optimize DBS programming in PD patients with problematic impulsivity or in other disorders involving impulsive behaviors such as substance use disorders.     

Characterizing impulsivity in mania

Objective: To determine whether specific aspects of impulsivity (response disinhibition, inability to delay gratification, inattention) differ between healthy and bipolar manic subjects, and whether these aspects of impulsivity were associated with each other and severity of affective symptoms. Methods: Performance of 70 bipolar I manic or mixed patients was compared to that of 34 healthy subjects on three tasks specifically designed to study response inhibition, ability to delay gratification, and attention; namely, a stop signal task, a delayed reward task, and a continuous performance task, respectively. Correlations among tasks and with symptom ratings were also performed. Results: Bipolar subjects demonstrated significant deficits on all three tasks as compared to healthy subjects. Performance on the three tasks was largely independent. Task performance was not significantly associated with the severity of affective symptom ratings. However, measures of response inhibition and attention were sensitive to medication effects. Differences in the delayed reward task were independent of medication effects or symptom ratings. During the delayed reward task, although bipolar patients made their choices more slowly than healthy subjects, they were significantly more likely to choose a smaller, but more quickly obtained reward. Moreover, performance on this task was not associated with performance on the other impulsivity measures. Manic patients showed more impulsive responding than mixed patients. Conclusions: Bipolar I manic patients demonstrate deficits on tests of various aspects of impulsivity as compared to healthy subjects. Some of these differences between groups may be mediated by medication effects. Findings suggested that inability to delay gratification (i.e., delayed reward task) was not simply a result of the speed of decision making or inattention, but rather that it reflected differences between bipolar and healthy subjects in the valuation of reward relative to delay.     

Aberrant orbitofrontal connectivity in marijuana smoking adolescents

IntroductionOrbitofrontal (OFC) circuits have been implicated in the pathophysiology of substance use disorders. The current study examined OFC functional connectivity differences in marijuana-using adolescents (MJ) and non-using healthy controls (HC).MethodsFunctional magnetic resonance imaging (fMRI) resting-state data were obtained on a 3 T MRI scanner on 31 HC and 43 heavy MJ smokers. Image analyses were performed between groups (MJ, HC) for the left and right OFC separately. Regression analyses between OFC functional connectivity and lifetime MJ use, age of first MJ use and impulsivity also were performed.ResultsIncreased OFC functional connectivity to frontal and motor regions was observed in heavy MJ users compared to HC. Earlier age of first MJ use was associated with increased functional connectivity of the right OFC to motor regions. High lifetime MJ use was associated with increased OFC functional connectivity to posterior brain regions in MJ youth.DiscussionFindings indicate atypical OFC functional connectivity patterns in attentional/executive, motor and reward networks in adolescents with heavy MJ use. These anomalies may be related to suboptimal decision making capacities and increased impulsivity. Results also suggest different OFC connectivity patterns may be present in adolescents with early onset of MJ use and high lifetime exposure to MJ.     

Genetic variation in components of dopamine neurotransmission impacts ventral striatal reactivity associated with impulsivity

Individual differences in traits such as impulsivity involve high reward sensitivity and are associated with risk for substance use disorders. The ventral striatum (VS) has been widely implicated in reward processing, and individual differences in its function are linked to these disorders. Dopamine (DA) plays a critical role in reward processing and is a potent neuromodulator of VS reactivity. Moreover, altered DA signaling has been associated with normal and pathological reward-related behaviors. Functional polymorphisms in DA-related genes represent an important source of variability in DA function that may subsequently impact VS reactivity and associated reward-related behaviors. Using an imaging genetics approach, we examined the modulatory effects of common, putatively functional DA-related polymorphisms on reward-related VS reactivity associated with self-reported impulsivity. Genetic variants associated with relatively increased striatal DA release (DRD2 -141C deletion) and availability (DAT1 9-repeat), as well as diminished inhibitory postsynaptic DA effects (DRD2 -141C deletion and DRD4 7-repeat), predicted 9-12% of the interindividual variability in reward-related VS reactivity. In contrast, genetic variation directly affecting DA signaling only in the prefrontal cortex (COMT Val158Met) was not associated with variability in VS reactivity. Our results highlight an important role for genetic polymorphisms affecting striatal DA neurotransmission in mediating interindividual differences in reward-related VS reactivity. They further suggest that altered VS reactivity may represent a key neurobiological pathway through which these polymorphisms contribute to variability in behavioral impulsivity and related risk for substance use disorders.     

Sensory processing in children with Autism Spectrum Disorder: Relationship with non-verbal IQ,autism severity and Attention Deficit/Hyperactivity Disorder symptomatology

The main objective of this study was to analyze in a sample of children with ASD the relationship between sensory processing, social participation and praxis impairments and some of the child's characteristics, such as non-verbal IQ, severity of ASD symptoms and the number of ADHD symptoms (inattention and hyperactivity/impulsivity), both in the home and main-classroom environments. Participants were the parents and teachers of 41 children with ASD from 5 to 8 years old (M = 6.09). They completed the Sensory Processing Measure (SPM) to evaluate sensory processing, social participation and praxis; the Gilliam Autism Rating Scale (GARS-2) to evaluate autism severity; and a set of items (the DSM-IV-TR criteria) to evaluate the number of inattention and hyperactivity/impulsivity symptoms in the child. Non-verbal IQ – measured by the Raven's Coloured Progressive Matrices Test – did not show a relationship with any of the SPM variables. The SPM variables were significant predictors of autism severity and had similar weights in the two environments. In the case of ADHD symptoms, the SPM variables had a greater weight in the home than in the classroom environment, and they were significant predictors of both inattention and hyperactivity/impulsivity – especially inattention – only in the family context. The moderate association between inattention and auditory processing found in the main-classroom suggests the possible utility of certain measures aimed to simplify any classroom's acoustic environment.