Impulsivity, intelligence and P300 wave: an empirical study.

The aim of this study was to analyze the relationships among impulsivity, intelligence and P300, a well-known component of the event-related potential widely studied in personality and intelligence research. Eighty-two males completed the Barratt Impulsiveness Scale and the two-subtest form of the Wechsler Abbreviated Scale of Intelligence. A subsample of 45 participants (mean age=24.4, SD=4.6) performed a visual oddball task, consisting of a two-letter recognition task, during which psychophysiological data were recorded. Although no significant relationships emerged for P300 latency, overall results suggest that the P300 amplitude was positively related to IQ and negatively related to impulsivity. Those who scored high on impulsivity (high impulsives) had lower P300 amplitudes than low impulsives, but this relationship was not significant when controlling for individual differences in mental ability. The results also showed an inverse relationship between mental ability and impulsivity. That is, high impulsives demonstrated reduced cognitive performance on intelligence testing and it is reflected in their reduced P300 amplitude. These findings are likely due to high impulsives' less efficient ability to inhibit task-irrelevant information or to ignore additional information intake. It was suggested that impulsivity exerts a disadvantageous influence on the performance of tasks (such as those used on intelligence tests) in which exclusive concentration and sustained attention are necessary.

Impulsive and premeditated subtypes of aggression in conduct disorder: differences in time estimation.

Research aimed at identifying and studying subtypes of aggression have historically dichotomized aggressive subtypes, although specific nomenclature has varied; one approach has been to classify aggressive behavior as predominantly impulsive or predominantly premeditated. There are a number of behavioral and cognitive differences between those exhibiting these different forms of aggression. This study was designed to extend understanding of the impulsive/premeditated aggression dichotomy by comparing time estimation among adolescents exhibiting predominantly impulsive or predominantly premeditated forms of physical aggression who have a psychiatric diagnosis of conduct disorder (CD). Time estimation has previously been shown to be disrupted in impulsive and some aggressive individuals. Time estimation was compared between healthy Controls (n = 37) and two groups of adolescents with CD, those with histories of either predominantly impulsive (CD-Impulsive, n = 26) or predominantly premeditated (CD-Premeditated, n = 38) aggressive behaviors. Participants completed five computerized trials during which they estimated when 1 min had passed. Among aggressive adolescents with CD, the misperception of time was specific to those with histories of impulsive aggression, although time estimates improved with repeated testing and performance feedback. This study confirms the importance of considering the role and type of physical aggression when studying heterogeneous diagnostic groups like CD and supports the relevance of time estimation to certain subgroups of adolescents with CD.

Manic symptoms and impulsivity during bipolar depressive episodes.

OBJECTIVES: In contrast to the extensive literature on the frequent occurrence of depressive symptoms in manic patients, there is little information about manic symptoms in bipolar depressions. Impulsivity is a prominent component of the manic syndrome, so manic features during depressive syndromes may be associated with impulsivity and its consequences, including increased risk of substance abuse and suicidal behavior. Therefore, we investigated the prevalence of manic symptoms and their relationships to impulsivity and clinical characteristics in patients with bipolar depressive episodes. METHODS: In 56 bipolar I or II depressed subjects, we investigated the presence of manic symptoms, using Mania Rating Scale (MRS) scores from the Schedule for Affective Disorders and Schizophrenia (SADS), and examined its association with other psychiatric symptoms (depression, anxiety, and psychosis), age of onset, history of alcohol and/or other substance abuse and of suicidal behavior, and measures of impulsivity. RESULTS: MRS ranged from 0 to 29 (25th-75th percentile, range 4-13), and correlated significantly with anxiety and psychosis, but not with depression, suggesting the superimposition of a separate psychopathological mechanism. Impulsivity and history of substance abuse, head trauma, or suicide attempt increased with increasing MRS. Receiver-operating curve analysis showed that MRS could divide patients into two groups based on history of alcohol abuse and suicide attempt, with an inflection point corresponding to an MRS score of 6. DISCUSSION: Even modest manic symptoms during bipolar depressive episodes were associated with greater impulsivity, and with histories of alcohol abuse and suicide attempts. Manic symptoms during depressive episodes suggest the presence of a potentially dangerous combination of depression and impulsivity.

Implicaciones prra el estudio de la neurobiologa de la experiencia consciente.. el acto impulsivo / Neurobiology o cconscious experience: implication of impulsive behavior

Consciousness and impulsivity are multidimensional constructs related to the control of thoughts and behavior. Impulsivity is a complex personality trait characterized by: acting without thinking, inability to plan ahead of time and poor attention or vigilance. Consciousness is a construct that encompasses a variety of physiological processes related to the experience of awareness and the acquisition of knowledge in human beings. With respect to the control of human behavior, consciousness and impulsivity appear to be related to opposite behaviors. Historically, efforts to understand these constructs by different disciplines have resulted in the development of divergent definitions and a variety of measures, thus causing confusion. The purposes of this article are to: 1) describe examples of solutions to this confusion within impulsivity research and discuss how consciousness research can benefit from the study of impulsivity; 2) discuss how consciousness and impulsivity can be measured within a laboratory and treated as experimental variables; 3) Summarize the lessons learned by comparing impulsive and premeditated acts from an integrated, multidimensional perspective; 4) Discuss the implications of a multidisciplinary model for pursuing consciousness research.

Conciencia e impulsividad son dos constructos multidimensionales relacionados con el control del pensamiento y comportamiento humano. Impulsividad es un rasgo de personalidad complejo caracterizado por una elevada tendencia a actuar sin pensar, incapacidad para planear actividades futuras y disminución de la capacidad de concentración. Conciencia por su parte, es un constructo que cobija una serie de procesos fisiológicos relacionados con la generación de experiencia conciente y la adquisición de conocimientos. Con respecto al control sobre la acción humana, conciencia e impulsividad parece estar relacionados con comportamientos opuestos. Históricamente, los esfuerzos realizados por diversas disciplinas con el fin de estudiar estos constructos han llevado al desarrollo de definiciones divergentes y a una serie de medidas, causando una mayor confusión. Los propósitos de este artículo son: 1) describir ejemplos de posibles soluciones al estado de confusión en el campo de la investigación sobre impulsividad y discutir como el estudio de la conciencia puede beneficiarse de la investigación de la impulsividad; 2) discutir algunas de las maneras utilizadas para medir impulsividad en el laboratorio y cómo hacer de estos constructos variables experimentales; 3) resumir algunas de las lecciones derivadas de la comparación de los actos impulsivos con los premeditados desde una perspectiva integral y multidimensional; 4) discutir las implicaciones derivadas del uso de un enfoque multidimensional para el estudio de la conciencia.

Impulsivity, aggressiveness, and DSM-IV personality disorders.

The aim of this study is to assess whether impulsive and aggressive traits can be placed on a continuum with DSM-IV Cluster B Personality Disorders (PDs) and to determine if different aspects of these personality traits are specifically associated with individual Cluster B PDs. The study group comprised 461 outpatients admitted consecutively to a clinic that specializes in the diagnosis and treatment of PDs. Principal component analyses clearly suggested a five-factor structure of both normal and psychopathological personality traits. Importantly, measures of impulsivity, aggressiveness and novelty seeking formed a part of the principal component that clustered all Cluster B PDs. Regression analyses indicated that impulsive traits were selectively associated with Borderline PD whereas different aspects of aggressiveness were useful in discriminating Narcissistic PD from Antisocial PD. Sensation seeking traits formed a part of Histrionic PD. These results indicate that impulsive/aggressive traits may be useful in explaining both why Cluster B PDs tend to covary, and why they frequently differ in clinical pictures and courses.

Impulsivity and BOLD fMRI activation in MDMA users and healthy control subjects.

The correlation between scores on the Barratt Impulsiveness Scale (BIS) and activation measured by functional magnetic resonance imaging in a dorsolateral prefrontal cortical (DLPFC) activating task was examined in 15 MDMA-using subjects and 19 controls. A significant correlation between BIS scores and DLPFC activation was found, supporting a role for the DLPFC in BIS-measured impulsivity.

Reduced punishment sensitivity in neural systems of behavior monitoring in impulsive individuals.

This study measured the response-locked event-related potential during a flanker task with performance-based monetarily rewarding and punishing trials in 37 undergraduate students separated into high- and low-impulsive groups based on a median split on self-reported Barrett Impulsiveness Scale. The high-impulsive group had a smaller medial frontal error-related negativity (ERN) on punishment trials than the low-impulsive group. The medial prefrontal neural system of behavior monitoring, indexed by the ERN, appears less sensitive to punishment signals in normal impulsivity. This reduced punishment sensitivity in impulsivity, a personality variation associated with several mental and personality disorders including ADHD and substance abuse may be related to the tendency to select short-term rewards despite potential long-term negative consequences in these individuals.

Reduced anterior corpus callosum white matter integrity is related to increased impulsivity and reduced discriminability in cocaine-dependent subjects: diffusion tensor imaging.

Brain imaging studies find evidence of prefrontal cortical dysfunction in cocaine-dependent subjects. Similarly, cocaine-dependent subjects have problems with behaviors related to executive function and impulsivity. Since prefrontal cortical axonal tracts cross between hemispheres in the corpus callosum, it is possible that white matter integrity in the corpus callosum could also be diminished in cocaine-dependent subjects. The purpose of this study was to compare corpus callosum white matter integrity as measured by the fractional anisotropy (FA) on diffusion tensor imaging (DTI) between 18 cocaine-dependent subjects and 18 healthy controls. The Barratt Impulsiveness Scale (BIS-11) and a continuous performance test: the Immediate and Delayed Memory Task (IMT/DMT) were also collected. Results of the DTI showed significantly reduced FA in the genu and rostral body of the anterior corpus callosum in cocaine-dependent subjects compared to controls. Cocaine-dependent subjects also had significantly higher BIS-11 scores, greater impulsive (commission) errors, and reduced ability to discriminate target from catch stimuli (discriminability) on the IMT/DMT. Within cocaine dependent subjects there was a significant negative correlation between FA in the anterior corpus callosum and behavioral laboratory measured impulsivity, and there was a positive correlation between FA and discriminability. The finding that reduced integrity of anterior corpus callosum white matter in cocaine users is related to impaired impulse control and reduced ability to discriminate between target and catch stimuli is consistent with prior theories regarding frontal cortical involvement in impaired inhibitory control in cocaine-dependent subjects.

P300 event-related potential amplitude and impulsivity in cocaine-dependent subjects.

Previous studies report reduced amplitude of the P300 event-related potential in cocaine-dependent individuals. Cocaine dependence is also associated with increased impulsivity, possibly due to deficits in cognitive function that are associated with reduced P300 amplitude. In the current study, the relationship between cocaine dependence, impulsivity, and P300 amplitude were examined. An auditory oddball event-related potential task along with self-report (Barratt Impulsiveness Scale version 11) and behavioral laboratory (Immediate and Delayed Memory Task) measures of impulsivity were assessed in healthy controls (n = 14) and subjects who met DSM-IV criteria for current cocaine dependence (n = 17). P300 amplitude was reduced and self-reported and behavioral laboratory impulsivity scores were elevated among the cocaine-dependent group compared to controls. There was a positive correlation between the questionnaire and behavioral laboratory measures of impulsivity, and a negative correlation between impulsivity measures and P300 amplitude. The correlation between self-reported impulsivity scores and P300 amplitude remained after taking into account the number of childhood conduct disorder symptoms. This study supports the hypothesis that the basic neurophysiology responsible for the P300 amplitude in cocaine-dependent individuals is associated with impulsivity independent of a history of childhood conduct disorder symptoms.

Predicting borderline and antisocial personality disorder features in nonclinical subjects using measures of impulsivity and aggressiveness.

This study examines impulsivity and aggressiveness dimensions as predictors of borderline (BPD) and antisocial (ASPD) personality disorder symptoms in nonclinical subjects. A total of 747 undergraduate university students were administered the Personality Diagnostic Questionnaire-4+, the Barratt Impulsiveness Scale-11, and the Buss-Durkee Hostility Inventory. Hierarchical regression analysis showed that motor impulsiveness, irritability, resentment, and guilt predicted BPD symptoms among university students after controlling for the effect of ASPD and depressive symptoms. ASPD symptoms were predicted by motor impulsiveness, physical aggression, indirect aggression, and negativism. These results indicate that in nonclinical subjects BPD and ASPD symptoms share a common impulsivity dimension but are linked to different aggressiveness facets.

Impulsive versus premeditated aggression: implications for mens rea decisions.

Science can provide more information about the nature of aggressive acts, and therefore the mens rea of criminal offenses, than is commonly assumed. For example, progress has been made in classifying aggression as impulsive or premeditated within the context of the role of conscious experience in controlling behavior. This review of the status of the scientific ability to distinguish conscious from unconscious acts and more specifically impulsive from premeditated aggressive acts is organized around four themes: (i) How is aggression defined and measured in general? (ii) How does the distinction between impulsive and premeditated aggression relate to the legal concept of mens rea? (iii) How do various scientific disciplines contribute to the mind/body discourse? (iv) What risk factors are associated with impulsive and premeditated aggression respectively? The authors conclude that the most promising approach to researching the nature of behavioral intention and motivation is to apply a discipline neutral model that integrates the data from multiple disciplines, collectively designated the cognitive neurosciences.

Psychometric properties of an adolescent version of the Barratt Impulsiveness Scale-11 for a sample of Italian high school students.

The purpose of this study was to extend the development of the Italian version of the Barratt Impulsiveness Scale for use with adolescents. The analyses which led to the development of this version were based on data from 563 high school students. The internal consistency was good (Cronbach alpha=.78). A confirmatory factor analysis identified six first-order factors which converged into two second-order factors, a General Impulsiveness factor and a Nonplanning Impulsiveness factor. The General Impulsiveness factor included motor and attention or cognition items. The second-order factors differed from those obtained with the adult Italian version as well as the American version. Possible reasons for these differences are discussed. The new version correlated significantly with self-report measures of aggression and Attention-Deficit/Hyperactivity Disorder as well as with frequency of alcohol use and cigarette smoking.

Increased impulsivity in cocaine dependent subjects independent of antisocial personality disorder and aggression.

Several previous studies show a relationship between impulsivity and substance abuse; however, it is unclear whether the increased impulsivity seen in substance dependent groups is specifically related to substance abuse, or if it is due to concomitant antisocial personality disorder (ASPD) or aggression. The issue of whether impulsivity is specifically related to substance abuse is important since it has a bearing on risk factors for development of substance abuse. To determine whether cocaine dependent subjects show increased impulsivity independent of ASPD, the Barratt impulsiveness scale (BIS-11), a delayed reward laboratory measure of impulsivity, and the life history of aggression scale were administered to 49 cocaine dependent subjects and 25 controls. Results showed that cocaine dependent subjects with ASPD were more impulsive and aggressive than controls, but cocaine dependent subjects without ASPD were also more impulsive compared to controls. Controlling for aggression history, cocaine dependent subjects without ASPD continued to have elevated impulsivity as measured by the BIS-11, but not the delayed reward task. This study supports the hypothesis that the increased impulsivity as measured by the BIS-11 in cocaine dependent individuals is not exclusively due to concomitant increases in aggression or ASPD.