Matthew S. Stanford

Factor structure of the barratt impulsiveness scale

The purpose of the present study was to revise the Barratt Impulsiveness Scale Version 10 (BIS-10), identify the factor structure of the items among normals, and compare their scores on the revised form (BIS-11) with psychiatric inpatients and prison inmates. The scale was administered to 412 college undergraduates, 248 psychiatric inpatients, and 73 male prison inmates. Exploratory principal components analysis of the items identified six primary factors and three second-order factors. The three second-order factors were labeled Attentional Impulsiveness, Motor Impulsiveness, and Nonplanning Impulsiveness. Two of the three second-order factors identified in the BIS-11 were consistent with those proposed by Barratt (1985), but no cognitive impulsiveness component was identified per se. The results of the present study suggest that the total score of the BIS-11 is an internally consistent measure of impulsiveness and has potential clinical utility for measuring impulsiveness among selected patient and inmate populations.

Neuropsychological and cognitive psychophysiological substrates of impulsive aggression

The purpose of this study was to test whether subjects who commit impulsive vs non-impulsive aggression differ on measurements of personality, neuropsychology, and cognitive psychophysiology, and whether these differences can yield information regarding the etiology of impulsive aggression. Subjects were two groups of prison inmates, distinguished by their committal of impulsive or nonimpulsive aggression, and matched noninmate controls. All inmates met DSM III-R criteria for an antisocial personality disorder but for no other disorder. Impulsiveness, anger, and peak P300 latencies did not differ between the inmate groups, but verbal symbol decoding and peak P300 amplitudes did. Impulsiveness and verbal skills were inversely correlated. Impulsiveness was inversely correlated with, and verbal skills positively correlated with P300 amplitudes. The results indicate that aggression is not homogenous, even among antisocial persons, and that impulsive aggression is related to neuropsychological and cognitive psychophysiological measures of information processing beyond those factors related to criminality alone.

The Effects of Phenytoin on Impulsive and Premeditated Aggression: A Controlled Study

Studies of the effects of phenytoin on aggression have produced equivocal results primarily because of a lack of (1) common objective criterion measures of aggressive acts across studies; (2) rigorous inclusion and exclusion criteria for selecting subjects; and (3) a nosologic basis for classifying different types of aggression. The current study was designed to remedy these deficiencies. Aggression was defined using a nosology that defines three types of aggression: (1) medically related; (2) premeditated; and (3) impulsive. The purpose of this study was to test the hypothesis that phenytoin will decrease impulsive aggressive acts but not have a significant influence on premeditated aggressive acts. Sixty inmates were divided into two groups on the basis of committing primarily impulsive aggressive acts or premeditated aggressive acts while in prison. Medical aggression was ruled-out by subject selection. The study used a double-blind, placebo-controlled, crossover design. As hypothesized, phenytoin (200 mg a.m. and 100 mg p.m.) significantly reduced impulsive aggressive acts but not premeditated aggressive acts. Event-related potentials (ERPs) measured information processing in the cortex during drug/placebo conditions. The amplitudes of P300 ERP waveforms among impulsive aggressive subjects were increased significantly during the phenytoin condition but not during the placebo condition. There were no significant changes in P300 ERP waveforms between drug/placebo conditions among nonimpulsive aggressive subjects.

Characterizing Aggressive Behavior

In the research literature, aggressive behavior has traditionally been classified into two distinct subtypes, impulsive or premeditated. Impulsive aggression is defined as a hair-trigger aggressive response to provocation with loss of behavioral control. Premeditated aggression is defined as a planned or conscious aggressive act, not spontaneous or related to an agitated state. The present study outlines the development of a clinically useful self-report instrument, the Impulsive/Premeditated Aggression Scales (IPAS), designed to characterize aggressive behavior as predominately impulsive or predominately premeditated in nature. The IPAS showed strong reliability and validity. Analysis of the IPAS scores demonstrated the presence of two types of aggressive behavior, impulsive and premeditated, in men referred for anger problems. The aggression of most individuals in the present sample was characterized as predominately impulsive in nature (90%).

Impulsiveness and risk-taking behavior: comparison of high-school and college students using the Barratt Impulsiveness Scale

The present study was undertaken in an attempt to determine the relationship of impulsiveness to risk-taking behaviors such as aggression, drug use, drunk driving and not wearing seatbelts among highschool and college students. The results of the study clearly demonstrate that high impulsives are involved in risk-taking behavior at a higher rate than low impulsive subjects. These findings suggest that high impulsive adolescents and young adults are at considerable risk of personal injury and present a potential source of injury to others. It is suggested that self-report questionnaires of impulsiveness might prove useful in the early identification of these high risk individuals. Once identified these individuals could be targeted for intensive educational interventions specifically designed to deal with their inability to delay gratification and general lack of impulse control. Language: en

Premeditated aggression: clinical assessment and cognitive psychophysiology

Aggressive behavior has traditionally been classified into two distinct subtypes: an affective, impulsive aggressive display or a planned, predatory aggressive act. While a number of investigations have examined the clinical and physiological correlates in impulsive aggressive individuals, very little research has been conducted on those individuals engaging in predominantly premeditated aggressive acts. The present study compared a group of premeditated aggressive psychiatric outpatients with a group of normal, non-aggressive control subjects on personality, neuropsychological and cognitive psychophysiological measures. Consistent with previous work, premeditated aggressors did not differ significantly from controls on most measures of neuropsychological and psychophysiological function. Premeditated aggressors did show significant personality pathology scoring higher on measures of impulsivity, verbal and physical aggression, anger, hostility, psychoticism and neuroticism. Overall, these results suggest a distinctive personality style that is associated with aggressive behavior. With respect to this and previous work, it is suggested that the physiological aspects of behavioral control play a key role in the type of aggressive behavior displayed.

New tricks for an old measure: The development of the Barratt Impulsiveness Scale-Brief (BIS-Brief)

The Barratt Impulsivity Scale (BIS), a 30-item self-report measure, is one of the most commonly used scales for the assessment of the personality construct of impulsiveness. It has recently marked 50 years of use in research and clinical settings. The current BIS-11 is held to measure 3 theoretical subtraits, namely, attentional, motor, and non-planning impulsiveness. We evaluated the factor structure of the BIS using full information item bifactor analysis for Likert-type items. We found no evidence supporting the 3-factor model. In fact, half of the items do not share any relation with other items and do not form any factor. In light of this, we introduce a unidimensional Barratt Impulsiveness Scale-Brief (BIS-Brief) that includes 8 of the original BIS-11 items. Next, we present evidence of construct validity comparing scores obtained with the BIS-Brief against the original BIS total scores using data from (a) a community sample of borderline personality patients and normal controls, (b) a forensic sample, and (c) an inpatient sample of young adults and adolescents. We demonstrated similar indices of construct validity that is observed for the BIS-11 total score with the BIS-Brief score. Use of the BIS-Brief in clinical assessment settings and large epidemiological studies of psychiatric disorders will reduce the burden on respondents without loss of information.

A comparison of anticonvulsants in the treatment of impulsive aggression.

This study compared the behavioral effects of 3 anticonvulsants in impulsive aggressive men. In a double-blind, placebo-controlled, parallel groups design, participants were randomly assigned to 1 of 4 6-week treatments: phenytoin (n = 7), carbamazepine (n = 7), valproate (n = 7), or placebo (n = 8). The efficacy measure was the average aggression score, a global severity index from the Overt Aggression Scale (J. M. Silver & S. C. Yudofsky, 1991). Analysis showed a significant reduction in impulsive aggression during all 3 anticonvulsant conditions compared with placebo. However, the treatment effect during carbamazepine administration was slightly delayed compared with phenytoin and valproate. These findings suggest that increased use of anticonvulsants could make a significant impact in the control of impulsive aggression in both mental health and criminal justice settings.

Characterizing aggressive behavior in a forensic population

The concept of a dichotomous versus a continuous aggression model continues to be debated within the research literature. The Impulsive/Premeditated Aggression Scale (IPAS; M. S. Stanford, R. J. Houston, C. W. Mathias, et al., 2003) is a newly developed self-report instrument designed to classify an individuals aggressive behavior as predominantly premeditated or predominantly impulsive. The IPAS consists of 30-items that are scored on a 5-point Likert scale. This study used a nonrandom sample of convenience (N = 85) from a forensic state hospital. Principal-components analysis of the 30 items revealed 2 distinct factors (Impulsive and Premeditated Aggression), which accounted for 33% of the variance. The results of this study further validate the bimodal classification of aggression through its application to a forensic sample. The implications for general assessment, diagnosis, and treatment are discussed.

Irritability and impulsiveness: relationship to self-reported impulsive aggression

Impulsive aggressive behavior was assessed in a group of 214 college students through self-report. All subjects completed the Anger Attack Questionnaire, Buss-Durkee Hostility Inventory (BDHI) and the Barratt Impulsiveness Questionnaire (BIS-11). Fifty-one subjects (24%) were classified as impulsive aggressive. Analysis of the BDHI and BIS-11 found that impulsive aggressive subjects scored significantly higher than nonaggressives on impulsiveness (BIS-11) and all subscales of the BDHI with the exception of Negativism and Suspicion. Correlation analysis demonstrated that impulsiveness and BDHI Irritability were significantly correlated with number of impulsive aggressive episodes in the previous month, while BDHI Assault was not. Impulsiveness was also found to be significantly related to BDHI Irritability but not to BDHI Assault. Irritability assesses an explosive, uncontrolled type of hostility; assault on the other hand assesses more of a provoked or retaliatory type of hostility which is not likely to be related to impulse control or impulsive aggression. The results of this study clearly demonstrate the usefulness of self-report data in the assessment of impulsive aggressive behavior. BDHI Irritability and BIS-11 impulsiveness both appear to be measuring similar aspects of behavioral control. It is suggested that the BDHI Irritability and BIS-11 scales may be useful in the identification of impulsive aggressive individuals early in their contact with the criminal justice and/or mental health systems.