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PubMed2026

Does impulsivity predict treatment outcomes in PTSD with borderline personality disorder features? Results from a randomized clinical trial.

BACKGROUND: Trauma-focused psychotherapies are first-line treatments for posttraumatic stress disorder (PTSD). However, a substantial proportion of clients do not respond adequately or drop out of therapy prematurely. This has sparked interest in identifying individual-level predictors of treatment outcomes, including improvement in PTSD severity and dropout. Impulsivity may be a predictor because it may interfere with key therapeutic processes, such as cognitive restructuring and emotional processing. Consequently, we present a hypothesis-driven secondary analysis of a 15-month randomized clinical trial comparing Dialectical Behavior Therapy for PTSD (DBT-PTSD) and Cognitive Processing Therapy (CPT) in women with childhood abuse-related PTSD and borderline personality disorder features to test whether impulsivity, assessed at baseline, predicts PTSD improvement and dropout. We further explore whether the dimensions of impulsivity (non-planning, attentional impulsivity, and motor impulsivity) differentially affect the outcomes in DBT-PTSD vs. CPT. METHODS: A total of 193 cis women with PTSD related to childhood abuse and borderline personality disorder features were assessed using the Clinician-Administered PTSD Scale (CAPS) and the Barratt Impulsiveness Scale (BIS-10). Separate probit models and general linear models were applied to predict dropout and pre-to-post changes in PTSD severity (ΔCAPS) from total impulsivity and subscale scores, i.e. non-planning, attentional and motor impulsivity. RESULTS: Overall, dropout rates were higher for participants with higher baseline impulsivity scores (p = 0.049), particularly for those with higher non-planning impulsivity (p = 0.012). In participants randomized to CPT improvement in PTSD symptom severity (ΔCAPS) was negatively related to baseline total impulsivity (p = 0.021). In participants randomized to DBT-PTSD this relation was not significant. CONCLUSIONS: The results suggest that impulsivity may predict treatment outcomes. Specifically, patients with elevated impulsivity may be less likely to respond adequately to CPT. If replicated, these findings have implications for personalization of treatment.

Humans↗

PubMed2026

Is impulsivity simply a failure of self-control? Evidence based on multi-omics analyses of genomics, metabolomics and brain imaging.

High impulsivity-a hallmark of various adverse life outcomes such as substance abuse, impulsive buying, violence, and crime-has typically been considered as a failure of self-control. However, is impulsivity simply a failure of self-control? To address this issue, we employed multi-omics combined with brain imaging approach in a large-scale sample (Nbrain imaging=1524, Ngenomics=835, Nmetabolomics=946) to elucidate the relationship between impulsivity and self-control. Mendelian randomization showed a bidirectional association between impulsivity and self-control, suggesting that they influenced each other. Partial least squares analysis highlighted that self-control primarily implicates the frontal lobe regions (e.g., superior frontal gyrus), whereas impulsivity involves the amygdala, insula, and basal ganglia. The cerebellum, superior frontal gyrus, and middle frontal gyrus were identified as shared areas in impulsivity and self-control. Furthermore, gene-based association analysis identified heterochromatin protein 1 binding protein 3 as specifically related to impulsivity, while pathway enrichment analysis demonstrated that arginine and proline metabolism was a common metabolic pathway associated with both impulsivity and self-control. Overall findings demonstrate that impulsivity and self-control involve both shared and distinct brain regions, genetic and metabolic foundations. The brain imaging results suggest that impulsivity is related not only to self-control-related processes but also to the motivation to pursue rewards. Together, this large-scale integrative study firstly provides a side-by-side map of genomic, metabolic, and limbic-network signatures of impulsivity distinct from self-control, offering a foundation for mechanism-driven biomarker and intervention research in maladaptive impulsivity.

Impulsive Behavior↗

PubMed2004

Early environmental experience alters baseline and ethanol-induced cognitive impulsivity: relationship to forebrain 5-HT1A receptor binding.

The relationship between impulsivity and drug abuse is poorly understood despite evidence that impulsive behaviour both predicts, and is a consequence of, drug use. Moreover, although there are clear individual differences in the propensity to addiction, this relationship has not been investigated with respect to impulsive behaviour. We tested whether early environmental experience would influence behavioural measures of impulsivity, and further, whether this experience would alter impulsive choice following ethanol intoxication. Thirty-six male, Long-Evans rats were reared in either isolated (1 rat/cage), standard (2 rats/cage), or enriched (group housed with toys) conditions. After a 3-month rearing period, animals were tested in two operant tasks measuring either motor (go/no-go) or cognitive (delay-to-reinforcement) impulsivity. Rats were then re-tested following 0, 0.3, 0.6, 0.9, and 1.2 g/kg ethanol. Forebrain 5-HT1A binding was assessed post-mortem using in vitro receptor autoradiography with the agonist [3H]8-OH-DPAT (3H-8-hydroxy-2-[di-n-propylamino]tetralin). Rearing condition did not influence baseline motor impulsivity, but isolation rearing led to decreased baseline cognitive impulsivity. Ethanol did not affect motor impulsivity, but dose-dependently increased impulsive choice in the delay-to-reinforcement task. Enriched rats were more impulsive overall, and isolation-reared rats only showed a shift in impulsive behaviour after 1.2 g/kg. Isolation rearing decreased, and enrichment rearing increased 5-HT1A binding in the frontal pole of the cortex following experience in the delay-to-reinforcement task. Isolation-reared rats also showed a significant decrease in 5-HT1A binding in the dentate gyrus of the ventral hippocampus following experience in the delay-to-reinforcement relative to the go/no-go task. These data indicate that differential rearing has a significant influence on cognitive impulsivity, and that altered serotonergic function may underlie these differences.

Age Factors↗

PubMed2001

Impulsive traits and 5-HT2A receptor promoter polymorphism in alcohol dependents: possible association but no influence of personality disorders.

OBJECTIVE: Impulsive behavior in alcoholics puts them at serious risk of severer course of disease and has been related to the serotonergic neurotransmission dysfunction. The aim of this study is to investigate the association between impulsive aggression in alcohol dependents with regard to the G-1438A polymorphism in the promoter region of the 5-HT2A receptor gene. Furthermore, we investigated the statistical interaction between 5-HT2A alleles, antisocial personality disorder (APD) and impulsive aggression in alcohol dependents. Alcohol dependents were investigated because these personality disorders and impulsive behavior are very frequent in alcohol dependence anf of clinical relevance. METHODS: One hundred and thirty-five patients of German descent meeting DSM-IV criteria of alcohol dependence were recruited. Blood samples were taken from alcohol dependents to determine 5-HT2A promoter polymorphisms using PCR (polymerase chain reaction) of lymphocyte DNA. Impulsive aggression was assessed using a German version of the Barratt Impulsiveness Scale which was translated and backtranslated. Alcohol dependents were subdivided into low- or high-impulsivity groups using a median split of the Barratt score. APD and borderline personality disorder (BPD) were assessed using the SCID-II interview. RESULTS: The low-impulsivity group was slightly older and showed a later age at alcoholism onset than the highly impulsive group. Alcohol dependents with high impulsive traits showed a significant association with 5-HT2A 1438 A alleles. After excluding alcohol dependents with APD or BPD from the analysis, this association remained significant. Furthermore, no association between APD, BPD and 5-HT2A alleles was noted. CONCLUSIONS: Inpatient alcohol dependents showed a significant association between 5-HT2A A alleles and impulsive traits, independent of the presence of APD or BPD. No association was noted between personality disorders and the polymorphism. This is the first report about an association of 5-HT2A promoter polymorphism and impulsive behavior in alcohol dependents. This finding may refer only to impulsive traits and may be independent of personality disorders in this sample. These results have to be confirmed in larger samples and in healthy control subjects to determine whether this association is of general validity.

Adult↗

PubMed1991

Effects of atrial impulse timing on AV concealed conduction in the rabbit heart.

The influence of the timing of a nontransmitted or transmitted atrial impulse on the atrioventricular (AV) conduction time of the subsequent impulse was studied in nine isolated rabbit hearts. AV conduction curves were determined by applying the atrial extrastimulus test. The extrastimulus was delivered preceded or not by an interposed atrial impulse whose coupling interval with respect to the last atrial beat of a basic train was kept constant at 100, 120, 140, 160, 175, 200, 225, 250, and 300 msec. In all experiments, there was a "concealment interval," i.e., the AV effective refractory period was longer than the atrial functional refractory period, and in seven experiments was comprised between 100 and 160 msec. For any given extrastimulus coupling interval in the presence of an interposed nontransmitted atrial impulse, AV conduction time was significantly greater than in its absence; the increase was greater than the longer the nontransmitted atrial impulse coupling interval, i.e., the shorter the subsequent transmitted impulse coupling interval with respect to the previous interposed nontransmitted impulse. The AV conduction curves relating the extrastimulus AV conduction time to its coupling interval with respect to the last atrial impulse of the basic train fitted to a hyperbolic model both in the absence of the interposed atrial impulse and in its presence (mean square residual 31 +/- 23 msec2), and the interposed atrial impulse modified the constants of the functions; the slope of the linear transformations was progressively more negative as the interposed atrial impulse was delayed. Furthermore, the effects of the interposed atrial impulse--transmitted or not--on AV conduction time of the subsequent impulse were qualitatively similar, their magnitude depending on the time elapsed were qualitatively similar, their magnitude depending on the time elapsed between the two.

Animals↗

PubMed1988

Nonlinear systems analysis of the hippocampal perforant path-dentate projection. III. Comparison of random train and paired impulse stimulation.

1. The transformational properties of the network of hippocampal neurons activated monosynaptically and polysynaptically by electrical stimulation of the perforant path were analyzed using random impulse train and paired impulse stimuli. In response to both types of input, the amplitudes of granule cell population spikes evoked in the dentate gyrus were used as the measure of network output. The random stimulus train consisted of a series of 4,064 electrical impulses, with interimpulse intervals determined by a Poisson distribution; the mean interimpulse interval of the train was 500 ms, and the range was 1-5,000 ms. Paired impulse stimuli consisted of pairs of impulses separated by 10-1,200 ms; impulses pairs were delivered once every 20 s. The procedures were applied to both anesthetized and chronically implanted, unanesthetized preparations. 2. Nonlinear systems analysis of population spike responses evoked during random train stimulation revealed that dentate granule cell output to any impulse was highly dependent on the interval since a prior impulse. Data from anesthetized animals showed that population spike amplitudes were markedly suppressed in response to intervals less than 50 ms, facilitated in response to intervals of approximately 100 ms, suppressed slightly in response to intervals of 300-700 ms, and unaffected by intervals greater than 700 ms. Data from unanesthetized animals showed similar results except that facilitation rather than suppression of spike amplitude was observed in response to intervals of 300-700 ms, and could extend to intervals as great as 1,000 ms. 3. The results of paired impulse stimulation applied to the same preparations also showed that granule cell response was highly dependent on interimpulse interval. However, nonlinearities observed with paired impulse stimulation differed from those revealed by a random impulse signal. Compared to results of random train stimulation, a paired impulse format produced greater magnitude spike suppression in response to short interimpulse intervals (e.g., 10-20 ms), maximum facilitation in response to shorter interstimulus intervals (50 ms rather than 100 ms), greater magnitude spike facilitation, and greater suppression in response to intervals greater than or equal to 300 ms. Furthermore, there were virtually no differences in the nonlinearities of granule cell response recorded from anesthetized and unanesthetized animals when a paired impulse format was used, whereas several differences were observed with random train stimuli. 4.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗

PubMed1999

Measures of impulsivity in cigarette smokers and non-smokers.

RATIONALE: Drug users are thought to be more "impulsive" than non-users. OBJECTIVES: This study examined whether regular smokers are more impulsive than never smokers using personality and behavioral measures of impulsivity. METHODS: Twenty regular smokers (>/=15 cigarettes/day) and 20 never smokers were recruited. Participants completed five personality questionnaires to assess impulsivity: Adjective Checklist, Barratt's Impulsivity Scale, the Tridimensional Personality Questionnaire, Eysenck's Personality Questionnaire, and the Sensation-Seeking Scale. Participants also performed three behavioral choice tasks designed to assess impulsivity. In the delay task, participants chose between small, immediate and large, delayed monetary rewards. Impulsivity was defined as a relative preference for the small, immediate alternative. In the probability task, participants chose between small, certain and large, uncertain monetary rewards. Impulsivity was defined as a relative preference for the large but more risky alternative. In the work task, participants chose between small monetary rewards obtained by performing a negligible amount of work and a larger amount of money requiring more work. Impulsivity was defined as a relative preference for the smaller, easier alternative. RESULTS: On the personality questionnaires, smokers had statistically higher impulsivity scores on most scales. On the behavioral choice tasks, smokers chose small, immediate money over large, delayed money more frequently, signifying greater levels of impulsivity. There were no differences between the groups' choices on the other tasks. Correlations between questionnaire and task data were small, as were correlations between data from each task. CONCLUSIONS: Together, these results indicate that the smokers were more impulsive than never smokers.

Adult↗

PubMed2005

Critical involvement of dopaminergic neurotransmission in impulsive decision making.

BACKGROUND: Impulsive decision making, apparent as intolerance for reinforcement delay, is prominent in attention-deficit/hyperactivity disorder. Commonly prescribed for this condition, amphetamine (Adderall), reduces impulsive decision making; however, the neuropharmacologic mechanism of this effect of amphetamine is unclear. METHODS: We investigated the involvement of dopaminergic and noradrenergic neurotransmission in impulsive decision making in rats, using a delayed reward task. RESULTS: Amphetamine and methylphenidate decreased impulsive decision making, which was mimicked by the selective dopamine reuptake inhibitor GBR 12909 but not by the noradrenaline reuptake inhibitor desipramine. Impulsive choice was increased by the dopamine D1 receptor antagonist SCH-23390 but not the dopamine D2 receptor antagonist eticlopride. The effect of amphetamine on impulsive choice was attenuated by pretreatment with eticlopride, whereas amphetamine retained its effect on impulsivity in the presence of SCH-23390. The alpha2 adrenoceptor agonist clonidine increased impulsivity, but the alpha1 adrenoceptor agonist phenylephrine did not affect impulsive decision making. CONCLUSIONS: These data demonstrate an important role for dopaminergic neurotransmission in impulsive decision making, whereby tolerance to delay of reinforcement depends on dopamine D1 receptor activation. Activation of dopamine D2 receptors appears to mediate the beneficial effects of amphetamine on impulsive behavior. Noradrenergic neurotransmission may play a minor role in impulsive choice.

Adrenergic Uptake Inhibitors↗

PubMed2003

Understanding impulsivity in severe depression? A psychometrical contribution.

BACKGROUND: Depression, especially severe depression, is strongly associated with suicidality. Impulsivity is one of the main dimensions of suicidality. The objective of this study was to assess the structure of impulsivity in severe depression and its relationships to suicide attempts. METHODS: 127 depressed in-patients were assessed at admission and after 4 weeks of treatment for depression and impulsivity with the Impulsivity Rating Scale (IRS) and the Impulse Control Scale (ICS) or the Baratt Impulsivity Scale (BIS). RESULTS: Three dimensions of impulsivity were evidenced in these severely depressed patients, i.e., behavioral loss of control, nonplanning and cognitive. These three dimensions are state dependent. Recent suicide attempts in severe depression are related to loss of control and cognitive impulsivity but not to nonplanning. IRS ad ICS may assess primarily behavioral impulsivity, i.e., loss of control and nonplanning, whereas BIS may assess primarily cognitive impulsivity. CONCLUSIONS: In the future, these three dimensions should be correlated to biological and genetic markers of impulsivity [serotonergic (5-HT) system] and prospective studies should assess the predictive value of the three dimensions of impulsivity in the occurrence of suicide attempts in depressed patients.

Adult↗

PubMed2024

Longitudinal characterization of impulsivity phenotypes boosts signal for genomic correlates and heritability.

Genomic correlates of impulsivity have been identified in several genome-wide association studies (GWAS) using cross-sectional designs, but no studies have investigated the molecular genetic correlates of impulsivity phenotypes using longitudinally constructed traits. In 3860 unrelated European participants in the Avon Longitudinal Study of Parents and Children (ALSPAC), we constructed longitudinal phenotypes for delay discounting and impulsive personality traits (as measured by the UPPS-P impulsive behavior scales) via assessment at ages 24, 26, and 28. We conducted GWASs of impulsivity using both cross-sectional and longitudinal phenotypes, estimated heritability and their phenotypic and genetic correlations, and evaluated their association with recently-developed polygenic risk scores (PRSs) for the impulsivity indicators themselves and also related psychiatric conditions. Latent growth curve modeling revealed a stable intercept over time for all impulsivity phenotypes. High genetic correlation of cross-sectional measures over time suggested a stable genetic component for delay discounting (rg = 0.53-0.99) and sensation seeking (rg = 0.99). Heritability estimates of the stable longitudinal phenotypes substantively improved as compared to their cross-sectional counterparts, revealing a significant SNP-heritability for delay discounting (0.22; p = 0.03) and sensation seeking (0.35; p = 0.0007). Consistent with previous reports, GWAS and gene-based analyses revealed associations between specific longitudinal impulsivity indicators and CADM2 and NCAM1 genes. The PRSs for the impulsivity indicators and disorders related to self-regulation were also significantly associated with longitudinal impulsivity traits. Finally, we validated the associations between longitudinal impulsivity phenotypes and their PRSs in an independent 13-wave longitudinal study (n = 1019) and the benefit of longitudinal phenotypes in simulation studies. In this first longitudinal genetic study of impulsivity traits, the results revealed stable genomic correlates of delay discounting and sensation seeking over time and further validated the utility of recently-developed PRSs, both in relation to the observed traits and in connecting them to psychiatric disorders. More generally, these findings support using latent intercepts as novel longitudinal phenotypes to boost signal for heritability and genomic correlates of mechanisms contributing to psychiatric disease liability.

Humans↗

PubMed2001

Psychiatric aspects of impulsivity.

OBJECTIVE: The authors discuss the relationship of impulsivity to psychiatric disorders and present selected hypotheses regarding the reasons for these relationships. METHOD: Previous research has shown significantly higher levels of impulsivity among patients with conduct disorder, personality disorders, substance use disorders, and bipolar disorder, compared to other psychiatric patients or healthy comparison subjects. A literature review of the theoretical bases of the relationship between these disorders and impulsivity is presented. Measurements of impulsivity and treatment options are discussed in relation to the physiology of impulsivity and the disorders in which it is a prominent feature. RESULTS: Impulsivity, as defined on the basis of a biopsychosocial approach, is a key feature of several psychiatric disorders. Behavioral and pharmacological interventions that are effective for treating impulsivity should be incorporated into treatment plans for these disorders. CONCLUSIONS: The high comorbidity of impulsivity and selected psychiatric disorders, including personality disorders, substance use disorders, and bipolar disorder, is in a large part related to the association between impulsivity and the biological substrates of these disorders. Before treatment studies on impulsivity can move forward, measures of impulsivity that capture the core aspects of this behavior need to be refined and tested on the basis of an ideologically neutral model of impulsivity.

Antipsychotic Agents↗

PubMed1981

Stochastic properties of gustatory impulse discharges in rat chorda tympani fibers.

1. The present study was intended to elucidate the role of temporal patterns of impulse discharges of the gustatory primary afferents in the coding of taste qualities by the use of simultaneous analyses of the across-neuron patterning (5) and the temporal patterning of impulses. 2. Impulse discharges of 43 rat chorda tympani fibers elicited by gustatory stimulation (0.1 M NaCl, 0.5 M sucrose, 0.01 N HCl, 0.02 M quinine hydrochloride, 0.3 M KCl, and 0.02 M saccharin sodium) were recorded. The temporal patterns of impulse discharges elicited by these stimuli were statistically analyzed both in an initial dynamic phase and a succeeding stationary phase of responses. In the dynamic phase, the time courses of firing frequency were studied; however, these were not clearly associated with the qualities of taste stimuli. In the stationary phase, the stochastic properties of impulse trains were studied regarding the impulse trains as a stochastic point process (30). In this study, interspike interval histograms (ISI histograms), joint interval histograms, serial correlograms, and autocorrelograms were computed. 3. In general, the distribution patterns of ISI histogram were not absolutely specific to the taste qualities. However, the gamma or the exponential distribution occurred most often with 0.1 M NaCl, and the bimodal or the skewed distribution was dominated with 0.5 M sucrose stimulation among the stimuli tested. The rhythmic discharges did not occur exclusively with the sweet taste stimulation, though they occurred more often with the sweet taste stimulation than with other taste stimulations. The joint interval histogram and the serial correlogram were used to examine the stochastic properties of impulse trains with particular reference to the time dependence in the impulse trains. Generally, the time dependence was not concerned with the taste qualities. 4. The chorda tympani fibers were classified into three types according to the magnitude of responses and the temporal patterns of impulse discharges. The neurons predominantly responsive to NaCl and unresponsive to sucrose were classified as type I neurons. The remaining neurons, which moderately responded to both NaCl and sucrose, were further categorized into type II neurons and type III neurons, depending on their temporal patterns of impulse discharge. The type II neurons tended to show the rhythmic or burstlike firing of impulses in response to more than one kind of taste stimuli. 5. The results showed that the taste quality was represented in the characteristic temporal patterning of impulses as well as in the across-neuron patterning of responses. The possible origin of the temporal discharge pattern and its significance in gustatory information processing were discussed on the basis of the neuron types described above.

Afferent Pathways↗

PubMed2004

Associations among aspects of impulsivity and eating factors in a nonclinical sample.

OBJECTIVE: Impulsivity has been well documented as a factor in the behavior of eating-disordered populations and is likely to influence normal eating patterns as well. The current study attempted to clarify the relationship between the three elements of impulsivity (nonplanning, attentional, and motor) and the three factors of eating (cognitive restraint, disinhibition, and hunger) in a nonclinical sample. METHOD: Data were collected from a sample (N = 112) of volunteer participants from the community who answered two self-report instruments related to impulsivity (the Barratt Impulsiveness Scale, Version 11) and eating (the Eating Inventory). Partial correlations were performed on the data to control for age, sex, and education. Cognitive restraint did not correlate with any element of impulsivity. Disinhibition was positively correlated with both attentional impulsivity (r = .40, p < .001) and motor impulsivity (r = .32, p < .01). Attentional impulsivity was also positively correlated with hunger (r = .24, p < .05). DISCUSSION: The lack of association between cognitive restraint and impulsivity suggests that they are functionally distinct. Disinhibition is most closely associated with impulsivity, consistent with findings from clinical samples. Further clarification of the relationship between impulsivity and eating in nonclinical populations could facilitate a better understanding of the relationship between personality variables and normal eating behavior.

Adolescent↗

PubMed2004

Impulsivity in smoking, nonsmoking, and ex-smoking alcoholics.

The impulsivity levels were evaluated and compared in smoking, nonsmoking, and ex-smoking abstinent alcoholics (N=400) in a French alcohol detoxification center. Impulsivity was measured using the Barratt Impulsiveness Scale, French version (BIS 10). The BIS scores correlated inversely with age. Gender had no effect on impulsivity scores, while impulsivity was associated with smoking. Adding age as a covariate, however, eliminated or moderated the association, with three exceptions: (1) among males, heavy smokers were more impulsive than nonsmokers and medium smokers; (2) on the nonplanning subscale, heavy smokers were more impulsive than all other groups, and (3) current smokers were more impulsive than ex-smokers. Elevated impulsivity levels appear to be an obstacle to smoking cessation. In addition, stopping smoking may diminish impulsivity levels in alcoholics. Routine testing of impulsivity in current alcoholic smokers might predict who might successfully become an ex-smoker.

Adolescent↗

PubMed2004

Genetic contributions to social impulsivity and aggressiveness in vervet monkeys.

BACKGROUND: Impulsivity contributes to multiple psychiatric disorders and sociobehavioral problems, and the more serious consequences of impulsivity are typically manifest in social situations. This study assessed the genetic contribution to impulsivity and aggressiveness in a social context using a nonhuman primate model. METHODS: Subjects were 352 adolescent and adult vervet monkeys from an extended multigenerational pedigree. Behavior was assessed in the Intruder Challenge Test, a standardized test that measures impulsivity and aggressiveness toward a stranger. Genetic and maternal contributions to variation in the Social Impulsivity Index and its two subscales, impulsive approach and aggression, were estimated using variance components analyses. RESULTS: The results found significant genetic contributions to social impulsivity (h2 =.35 +/-.11) and to each of the subscales, with no significant influence of maternal environment. There was a high genetic correlation between the impulsive approach and aggression subscales (rho =.78 +/-.12). CONCLUSIONS: This is the first study to demonstrate heritability of social impulsivity in adolescents and adults for any nonhuman primate species. The high genetic correlation suggests the same genes may influence variation in both impulsive approach and aggression. These results provide a promising basis for identification of susceptibility loci for impulsivity and aggressiveness.

Age Factors↗

PubMed2003

Response inhibition and impulsivity: an fMRI study.

Aggressive, suicidal and violent behaviour have been associated with impulsive personality and difficulty in inhibiting responses. We used functional magnetic resonance imaging (fMRI) of the whole brain to examine the neural correlates of response inhibition in 19 normal subjects as they performed a Go/NoGo task. Subjects completed Eysenck's Impulsivity Scale, Barratt's Impulsivity Scale (BIS) and behavioural impulsivity tasks. Associations between blood oxygen level dependent (BOLD) response, trait impulsivity, task performance and National Adult Reading Test (NART) IQ were investigated. Neural response during response inhibition was most prominent in the right lateral orbitofrontal cortex. Responses were also seen in superior temporal gyrus, medial orbitofrontal cortex, cingulate gyrus, and inferior parietal lobule, predominantly on the right side. Subjects with greater scores on impulsivity scales and who made more errors had greater activation of paralimbic areas during response inhibition, while less impulsive individuals and those with least errors activated higher order association areas. Exploratory factor analysis of orbital activations, personality measures and errors of commission did not reveal a unitary dimension of impulsivity. However, the strong association between posterior orbital activation and Eysenck's impulsivity score on a single factor suggests that greater engagement of right orbitofrontal cortex was needed to maintain behavioural inhibition in impulsive individuals. Lower IQ was more important than impulsivity scores in determining errors of commission during the task. Neuroimaging of brain activity during the Go/NoGo task may be useful in understanding the functional neuroanatomy and associated neurochemistry of response inhibition. It may also allow study of the effects of physical and psychological interventions on response inhibition in clinical conditions such as antisocial personality disorder.

Adolescent↗

PubMed1993

Impulsivity and eating disorders.

Sixty-seven patients with bulimia nervosa and 29 patients with anorexia nervosa completed the Impulsiveness Questionnaire and questionnaires detailing severity of eating disorder. Bulimic patients had higher impulsivity scores than anorexic patients. Bulimics with high impulsivity scores did not have more severe eating disorders than low scorers. When 39 bulimics and 25 anorexics were interviewed about other impulsive behaviour, 51% of bulimics and 28% of anorexics reported at least one other impulsive behaviour. Patients with so-called 'multi-impulsive' bulimia reported more severe eating disturbance, but this was not reflected on more reliable measures of symptoms. Thirty-nine bulimics entered an eight-week treatment trial and their progress was assessed at eight weeks, 16 weeks and one year. 'Non-impulsive' bulimics had a more rapid response than 'impulsives' during treatment, but there was no difference at follow-up. There was no evidence of an association between high impulsivity trait scores and poor treatment response. It is concluded that impulsivity may shape the expression of eating disorders, but that 'multi-impulsives' do not constitute a categorically distinct subgroup of bulimics.

Adult↗

PubMedDate not supplied

[Impulsiveness in children with hyperkinetic syndrome].

As research on impulsive behaviour in hyperactive children has been rather neglected, this study first measured impulsivity using several instruments and then compared the outcomes. 31 boys with ADHD participated in this study as well as an equal sized male control group (mean age 9;4 years). Each subject completed two computerised tests of impulsivity: the Delay of Gratification Test (DGT) as well as the Continuous Performance Test (CPT). Additionally, the boy's impulsive behaviour was rated by two questionnaires for teachers (the Teacher Report Form, TRF, and the Conners Teacher Rating Scale, CTRS). Apart from impulsive behaviour the motor activity was measured, as the classification systems ICD-10 and DSM-IV differ on the concepts of "impulsivity" and "hyperactivity". The assessment was undertaken using a radar-actometer in order to find an association between "impulsivity" and "hyperactivity". As expected, there was a significant difference between the two groups concerning impulsive behaviour and motor activity. As opposed to that result, the correlations of the several instruments that measure impulsive behaviour were not constantly significant. The impulsivity-item on the CTRS is not associated with the CPT and correlates moderate significantly with the DGT. These results led to the development of a model that includes the construct of "impulsivity" as separate dimension of ADHD.

Aggression↗