High Aggression Group Research Articles

Aggressive and Prosocial Peer Group Functioning: Effects on Children's Social, School, and Psychological Adjustment

AbstractThis study examined the effects of aggressive and prosocial contexts of peer groups on children's socioemotional and school adjustment. Data on informal peer groups, social functioning, and different aspects of adjustment were collected from multiple sources in a sample of elementary school children (149 boys, 181 girls; M age = 10 years). Multilevel analyses indicated that group aggressive and prosocial orientations made direct contributions to children's social, school, and psychological functioning. Group contexts also moderated the individual‐level relations between social behavior and self‐perceptions; prosocial behavior was associated with social or scholastic self‐perceptions more evidently in low prosocial and high aggressive groups. The results suggest that the peer group is an important context for children's performance and adjustment in various domains.

MDMA-induced serotonergic neurotoxicity enhances aggressiveness in low- but not high-aggressive rats

Ecstasy or 3,4-methylenedioxymethamphetamine (MDMA) is a frequently (ab)used recreational drug for its acute euphoric effects but on the long-term may cause neurotoxic damage to serotonin (5-hydroxytryptamine; 5-HT) nerve endings in the brain. Since decreased brain 5-HT function has been strongly associated with several impulse control disorders like hostility and violent aggression, ecstasy users might be at risk developing this form of psychopathology. The present study examined the ability of a MDMA administration protocol (3 × 6 mg/kg, with 3 h intervals at 25 ºC ambient temperature), that previously was shown to partially deplete brain serotonin levels, to increase offensive aggressive behavior in male Wild-type Groningen (WTG) rats. This rat strain is known for its broad individual variation in offensive aggression. Resident-intruder aggression was assessed 5 days before and 23 days after MDMA administration. On day 28, MDMA neurotoxicity to 5-HT nerve terminals was assessed by quantification of serotonin reuptake transporter (SERT) immuno-positive axons in defined brain regions. Based on their expressed aggression level in the initial aggression test, rats were divided into low (< 10% aggression), high (> 50% aggression) or medium aggressive (10–50%) groups. The study demonstrated that MDMA treatment increased aggressiveness in only low aggressive rats and not in medium and high aggressive animals. Irrespective of their initial aggressiveness, MDMA significantly reduced the number of SERT-positive axons in all animals. In conclusion, vulnerability for increased aggression long after a single MDMA treatment is dependent on the individual's trait aggressiveness but not on the degree of MDMA-induced serotonergic neurotoxicity.

Trait Aggressiveness Modulates Neurophysiological Correlates of Laboratory-induced Reactive Aggression in Humans

Reactive aggression following provocation is a frequent form of human social behavior. The neural basis of reactive aggression, especially its control, remains poorly understood, however. We conducted an event-related potential (ERP) study using a competitive reaction time task that elicits aggression through provocation. Participants were selected from a larger sample because of extreme scores in trait aggressiveness, yielding high and low trait aggressive groups. As each trial in the task is separated into a decision phase, during which the punishment level for the opponent is set, and an outcome phase, during which the punishment is applied or received, we were able to disentangle provocation-related and evaluation-related modulations of the ERPs during the aggressive interaction. Specifically, we observed an enhanced frontal negativity during the decision phase under high provocation that was positively correlated with the participants' ability to refrain from retaliation. This held true for high trait aggressive participants only, pointing to a higher need for inhibitory and control processes in these people when provoked. During the outcome phase, we detected a mediofrontal negativity in loss compared to win trials, resembling previous ERP findings to negative feedback stimuli, which have been linked to the evaluation of an outcome's valence. This mediofrontal negativity was differentially pronounced in aggressive and nonaggressive participants: Nonaggressive participants showed only a slightly smaller mediofrontal negativity in win than in loss trials, suggesting that for them punishing the opponent had a similar negative valence as being punished.

Hypothalamic–pituitary–adrenal axis activity, dehydroepiandrosterone sulphate and their relationships with aggression in early and late alcohol withdrawal

The study aims at investigating the relationship between hypothalamic–pituitary–adrenal (HPA) axis alterations and aggression level in alcoholic patients during early and late alcohol withdrawal. Serum levels of basal cortisol and dehydroepiandrosterone sulphate (DHEAS) were measured three times, and cortisol and DHEAS response to dexamethasone twice during the early and late withdrawal periods in alcohol dependent males ( n = 30) and once in healthy control males ( n = 20). Abnormal cortisol non-suppression response to dexamethasone in dexamethasone suppression test (DST) was observed in some proportion of the patients in early withdrawal, which normalized in late withdrawal. The study revealed reduced basal DHEAS levels and reduced DHEAS response to dexamethasone in late withdrawal. When the patients were assessed in two separate groups as high- and low-aggressives, in the high-aggression group abnormality in DST was observed during both early and late withdrawal periods, in the low-aggression group it was observed only in early withdrawal. While basal DHEAS levels were low in the high-aggression group only in early withdrawal, it was reduced in the low-aggression group during late withdrawal period. Some alterations of the HPA axis during alcohol withdrawal might be associated not only with alcohol use per se but also with aggressivity tendency of alcoholic patients.

THYROID FUNCTION IN EARLY AND LATE ALCOHOL WITHDRAWAL: RELATIONSHIP WITH AGGRESSION, FAMILY HISTORY, AND ONSET AGE OF ALCOHOLISM

Thyroid dysfunction is a known finding in alcoholism. Most studies have reported the reduction in peripheral thyroid hormones in acute withdrawal and long-term abstinence periods of alcohol dependence. The aim of the present study was to investigate the alterations of free thyroid hormones in early and late withdrawal and their association with aggression, age of onset, and family history of alcoholism. Male inpatients (n = 39; mean age +/- SD: 42.55 +/- 8.02 years) in alcohol withdrawal were compared with healthy men (n = 28; mean age +/- SD: 38.31 +/- 9.26 years). Levels of free thyroxine (fT4), free triiodothyronine, (fT3) and thyrothrophin (TSH) were measured in early (first day) and late (28th day) withdrawal in the patients and only once in the controls. In early withdrawal, levels of thyroid hormones did not differ from those in the controls. In late withdrawal, fT3 and fT4 levels (2.71 +/- 0.56 and 10.80 +/- 1.86 pg/ml) were lower than those of both controls (3.32 +/- 0.41 and 11.95 +/- 1.49 pg/ml, respectively, P < 0.05 in both cases) and patients in early withdrawal (3.18 +/- 0.72 and 12.68 +/- 2.50 pg/ml, respectively, P < 0.05 in both cases). Patients were divided into subgroups according to aggression level, onset age of alcoholism, and family history. While the high-aggression group had lower serum levels of fT3 and fT4 in late withdrawal (2.49 +/- 0.41 and 10.44 +/- 2.15 pg/ml) compared with those of controls (P < 0.05 in both cases), the low-aggression group only had lower serum levels of fT3 in late withdrawal (2.90 +/- 0.62 pg/ml) compared with those of controls (P < 0.05). fT3 and fT4 values in the family history-negative group (2.67 +/- 0.56 and 10.75 +/- 1.88 pg/ml) were lower than those of controls in late withdrawal (P < 0.05 in both cases). Both fT3 and fT4 levels in late withdrawal (2.69 +/- 0.54 and 10.83 +/- 1.96 pg/ml) were decreased in early-onset group compared with those of controls (P < 0.05 in both cases). Decreased free thyroid hormone levels may be a result of heavy alcohol consumption or a trait marker of alcoholism, especially in high-aggressive, early-onset and family history-negative patients.

Exteroceptive suppression of temporalis muscle activity in subjects with high and low aggression traits

Study aim There is evidence that the second exteroceptive suppression period of temporalis muscle activity (ES2) is modulated by the 5-HT neuronal activity in the brainstem, and the aggression trait is also connected with the cerebral 5-HT neuronal innervation. We therefore studied the temporalis ES2 in subjects with high and low aggression traits. Methods Sixty-five subjects with either low or high aggression trends, judged by clinical interview, answered the Zuckerman–Kuhlman Personality Questionnaire (ZKPQ), the Zuckerman Sensation Seeking Scales (SSS) and the Plutchik–van Praag Depression Inventory (PVP). These also underwent a temporalis ES2 test procedure. Twenty-two subjects with a high ZKPQ aggression trait score and 27 with a low score were selected for data analysis. Results On average, the high aggression group displayed significantly reduced temporalis ES2 duration, elevated ZKPQ Impulsive Sensation Seeking, Neuroticism-Anxiety and Aggression-Hostility, and PVP scores. The personality traits were not related with either latency or duration of temporalis ES2 in any group. The PVP score, however, was negatively correlated with ES2 duration in all 49 subjects. Conclusions This study demonstrates neurophysiologic signs of brainstem dysfunction in subjects with high aggression traits.

Peer group aggressiveness and the use of coercion in police–suspect encounters

The aim of this paper is to add the dimension of police ‘peer group’ to our understanding of how officers exercise coercive power in day‐to‐day encounters with citizens. Using data from the Project on Policing Neighborhoods (POPN) collected in St Petersburg, Florida, we examine 1,458 police–suspect encounters to determine whether collective peer group attitudes towards aggressive patrol influences police use of force behavior. Analysis of the direct effect of peer groups’ attitudes toward aggressiveness on the use of force indicates it is not a significant predictor when officer, suspect, and situational characteristics are controlled. Models comparing officers across high and low aggressive peer groups, however, indicate that different factors are salient to the use of higher levels of force across those groups. The implications of these findings and future research are discussed.

Can gene expression profiling predict survival for patients with squamous cell carcinoma of the lung?

BackgroundLung cancer remains to be the leading cause of cancer death worldwide. Patients with similar lung cancer may experience quite different clinical outcomes. Reliable molecular prognostic markers are needed to characterize the disparity. In order to identify the genes responsible for the aggressiveness of squamous cell carcinoma of the lung, we applied DNA microarray technology to a case control study. Fifteen patients with surgically treated stage I squamous cell lung cancer were selected. Ten were one-to-one matched on tumour size and grade, age, gender, and smoking status; five died of lung cancer recurrence within 24 months (high-aggressive group), and five survived more than 54 months after surgery (low-aggressive group). Five additional tissues were included as test samples. Unsupervised and supervised approaches were used to explore the relationship among samples and identify differentially expressed genes. We also evaluated the gene markers' accuracy in segregating samples to their respective group. Functional gene networks for the significant genes were retrieved, and their association with survival was tested.ResultsUnsupervised clustering did not group tumours based on survival experience. At p < 0.05, 294 and 246 differentially expressed genes for matched and unmatched analysis respectively were identified between the low and high aggressive groups. Linear discriminant analysis was performed on all samples using the 27 top unique genes, and the results showed an overall accuracy rate of 80%. Tests on the association of 24 gene networks with study outcome showed that 7 were highly correlated with the survival time of the lung cancer patients.ConclusionThe overall gene expression pattern between the high and low aggressive squamous cell carcinomas of the lung did not differ significantly with the control of confounding factors. A small subset of genes or genes in specific pathways may be responsible for the aggressive nature of a tumour and could potentially serve as panels of prognostic markers for stage I squamous cell lung cancer.

Role of Aggressivity on Reactivity and Craving before and after Cue Exposure in Recently Detoxified Alcoholics: Results from an Experimental Study

The role of aggressivity and cue exposure in induction of craving were investigated in a clinical setting. Thirty abstinent alcoholic patients were divided into a low and a high aggressive group based on scores on the physical aggression subscale of the Buss-Durkee Hostility Inventory and exposed to alcohol cues. Craving was measured by means of the Alcohol Craving Questionnaire (ACQ) and Visual Analogue Scales (VAS). Important findings are: (1) main effects of aggressivity on ‘emotionality’, ‘purposefulness’ and ‘expectancy’ of ACQ were very significant; (2) on ‘drinking intention’ and ‘craving for alcohol’ of VAS, aggressivity and cue exposure showed a significant interaction; (3) the main effect of cue exposure on heart rate also reached a significance level of 0.007. The results were discussed in the context of the Classical, Operant Conditioning Theory, the Cognitive Craving Theory of Tiffany, Gilbert’s STAR Model, and the Self-Medication Hypothesis

Parental and early childhood predictors of persistent physical aggression in boys from kindergarten to high school.

In a prior study, we identified 4 groups following distinct developmental courses, or trajectories, of physical aggression in 1037 boys from 6 to 15 years of age in a high-risk population sample from Montréal, Québec. Two were trajectories of high aggression, a persistently high group and a high but declining group. The other 2 trajectories were a low group and a moderate declining group. This study identified early predictors of physical aggression trajectories from ages 6 to 15 years. In this study, logistic regression analysis was used to identify parental and child characteristics that distinguished trajectory group membership. For boys displaying high hyperactivity and high opposition in kindergarten, the odds of membership in the 2 high aggression groups were increased by factors of 3.0 (95% confidence interval [CI], 2.0-4.3) and 2.7 (95% CI, 1.9-3.8), respectively, compared with boys without these risks. Counterpart odds ratios for the risk factors of mothers' teen-onset of parenthood and low educational attainment were 1.6 (95% CI, 1.1-2.2) and 1.8 (95% CI, 1.3-2.4), respectively. Only the maternal characteristics distinguished between the trajectory of persistently physical high aggression and the trajectory starting high but subsequently declining. For the 2 maternal risk factors combined, the odds ratio of persisting in high level physical aggression was 9.4 (95% CI, 2.9-30.4). Kindergarten boys displaying high levels of opposition and hyperactivity are at high risk of persistent physical aggression. However, among kindergarten boys who display high levels of physical aggression, only mothers' low educational level and teenage onset of childbearing distinguish those who persist in high levels of physical aggression.

Aggressive disposition, alcohol, and aggression

This study investigated the effect of aggressive disposition on intoxicated and non-intoxicated aggressive behavior, Prior aggressiveness was measured with a structured questionnaire, Based on a bipartite split of scores, 28 subjects were assigned to the high aggressor group, and 29 to the low aggressor group. Subjects in both disposition groups were then randomly assigned to either a drunk or sober condition, and participated in a competitive reaction time task involving the administering and receiving of electric shocks to/from a fictitious opponent under conditions of high and low provocation. Aggression was defined as shock level intensity delivered to the sham opponent. When highly provoked, sober high aggressors were significantly more aggressive than low aggressors, thus validating the measure of aggressive disposition. When intoxicated, highly provoked individuals in both the high and low aggressive disposition groups attained equal levels of aggression, It was low aggressors who responded to escalated provocation with a significant increase in aggression responding when intoxicated. These results lend support to the notion that a pharmacological effect of alcohol can increase aggressive behaviour.

The relationship between aggressive behavior and puberty in normal adolescents: A longitudinal study

Purpose: To assess changes in aggressive behaviors as related to progression from early to late puberty in normal adolescents. Methods: Subjects were normal English schoolchildren. An observational cohort design was employed. Pubertal status was measured by Tanner staging. Self-reports of verbal aggression against adults, physical aggression against peers, aggressive impulses and aggressive inhibitory responses, were collected at three points in time. Analyses were performed for the entire group of 106 subjects in 1983, 77 subjects in 1985 and 70 subjects in 1987. Statistical methods included analysis of variance, regression and correlation and cluster formation. Results: There were decreases in all aggression variables except in aggressive impulses over this time period. When analyzed by gender, boys were initially more aggressive than girls, but by late puberty all gender differences in self-reported aggressive behaviors had disappeared. When only those subjects who were evaluated at all three data collection times were grouped by similar responses on both aggression and physical variables, three clusters of boys and girls were identified. Clusters contained varying proportions of boys and girls. Cluster one (48.5% of the entire sample) was a low aggression group. Cluster two (30.3%) was a high aggression group, and cluster three (21.2%) was an intermediate aggression group. These clusters seemed to have relatively stable aggression characteristics over time. Conclusions: These data suggest that groups of boys and girls who report similar aggression characteristics and have similar growth and pubertal characteristics can be identified. Neither gender alone, nor pubertal status alone, nor by inference, hormones alone is sufficient to explain the complex set of behaviors which are involved in aggression.

Aggression in boys with attention deficit-hyperactivity disorder: methylphenidate effects on naturalistically observed aggression, response to provocation, and social information processing.

High and low-aggressive boys with attention deficit-hyperactivity disorder (ADHD) were compared and the effects of methylphenidate were examined on measures from three domains of aggression: (1) directly observed verbal and nonverbal aggressive behaviors exhibited in the context of a day treatment program, (2) aggressive responding when provoked during a laboratory task, and (3) social information processing patterns exhibited on tasks designed to tap the putative cognitive components of aggression. The high-aggressive (HA) and low-aggressive (LA) subgroups differed significantly on observational measures of aggression and on the laboratory provocation task, but the HA group showed more deviant cognitions on only one of the numerous measures of social information processing. Regarding medication effects on the direct observation measures, methylphenidate decreased aggression for both subgroups. On the laboratory provocation task, methylphenidate had only minimal effects. Significant drug effects were obtained on only two recall social information processing measures.

A four-fold model for subgrouping the Hyperkinetic/MBD Syndrome

The major finding of this study is that the presence or absence of aggressive symptomatology differentiates a group of 84 six to twelve year-old Hyperkinetic/MBD boys on a number of important measures at initial referral, during treatment with methylphenidate, and at subsequent five-year-follow-up. When the sample is sorted into high and low aggression groups, several findings emerge which would otherwise have been obscured. Furthermore, there are no significant interactions between aggression (control deficits, negative affect, aggressive interpersonal behavior) and hypertactivity (judgment deficits, hyperactivity, inattention). The value of differentiating between exclusive hyperactivity with aggression) is indicated by the present study.

Aggression, performance variables, and anger self-report in ice hockey players.

This study partially replicated a former one showing a relationship between aggression and performance among hockey players. With certain penalties used as a measure of aggression, two groups of male college ice hockey players were compared for differences in goals and assists. Those rated high in aggression scored significantly more goals than those low in aggression. The direction of differences in assists was the same but did not reach significance. When the same groups were compared for shots on goals, significant differences were found, favoring the high aggressive group. This findings was discussed in light of energy output and efficiency. Attempts to relate performance and personality measures were not successful when comparisons on a self-report measure of anger were analyzed.

Comparison of regional serotonin levels and turnover in the brain of naturally high and low aggressive rats

Rats, matched by weight and goal approach, were tested for aggressiveness using a food-competition paradigm. Those winning and those losing all of their matches were designated as high and low aggressive, respectively. A third group of randomly selected rats never fought and were used as a control for the fighting experience. Half of the rats were used to determine serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in discrete brain regions. The other half were used to estimate 5-HT turnover in the same brain regions. High and low aggressive rats did not differ with regard to 5-HT or 5-HIAA levels, but high aggressive rats showed faster 5-HT turnover than low aggressive rats. The turnover differences reached statistical significance in only two of the 3 brain regions examined: (a) all structures (minus olfactory bulbs) rostral to the level of the anterior commissure, and (b) the brain stem (hypothalamus-midbrain-medulla). The observed differences cannot be attributed to differing behavioral experiences since the high and low aggressive groups pooled did not differ from the no-fighting control. These findings are discussed with respect to the involvement of serotonin in rat intraspecies aggression.

THE EFFECTS OF COMPETITION ON HEART RATE AND TASK PERFORMANCE IN THE MIRROR DRAWING TEST

The aims of the present study were to elucidate the effects of competitive situatioin on heart rate and task performance in the mirror drawing test.The subjects were forty junior college women. In accordance with the score of Taylor's MAS, two groups of the anxiety level; high anxiety group (N=20), moderate anxiety group (N=20) were set. They were tested on the mirror drawing test under the non-competitive and competitive conditions. After the test, Buss-Derkee's HGS and other questionnaire were carried out. The results indicated that:1. Under the competitive condition, heart rate increased in both high and moderate anxiety groups, and there was no difference betweentwo grovps. The speed of the mirror drawing test increased under the competitive condition, but the accuracy was impaired. It was conspicuous in moderate anxiety group.2. Under the competitive condition, there was difference between heart rate in high and low aggression groups (respectively, N=8) divided by HGS. Heart rate in low aggr ssion group increased greater than that in high aggression group.

The relation between Rorschach signs of aggression and behavioral aggression in emotionally disturbed boys.

Abstract Ratings of aggressive behavior were related to Rorschach signs of aggression for sixty-three boys at a residential treatment school for children. The total list of 26 Rorschach signs was significantly correlated with the ratings, but much of this relationship was contributed by only a few individual signs. Indices of aggressive impulses, such as aggressive content, were not significant, while the more structural indices, considered as measures of impulse control, (presence of CF and absence of human movement responses), were significantly related to the behavior ratings. Presence or absence of human responses alone differentiated between low aggression and high aggression groups about as well as did a combination of indices.