Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “aggression”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1995

Aggressiveness, competitiveness, and human sexual orientation.

Previous research has suggested that homosexual men are less aggressive than heterosexual men, but limitations of available studies prevent them from being conclusive. The empirical evidence is even more mixed regarding the relation of aggressiveness to female sexual orientation. We examined the relation between self-reported physical and verbal aggressiveness, interpersonal competitiveness, and sexual orientation in both men and women. The aggressiveness and competitiveness scales yielded significant sex differences, with men being more aggressive and competitive. Consistent with past findings, heterosexual men were more physically aggressive than were homosexual men; no other within-sex relationship was significant. We discuss the implications of our findings for developmental theories of sexual orientation, aggressiveness, and competitiveness.

Adult↗
PubMed2005

Effects of L-DOPA on aggressive behavior and central monoaminergic activity in the lizard Anolis carolinensis, using a new method for drug delivery.

The dopamine (DA) precursor, L-DOPA (500 microg), was injected into living crickets, which were ingested (one each) by adult male Anolis carolinensis. This method of delivery elevated plasma L-DOPA and DA concentrations by approximately 1000-fold. In contrast, plasma epinephrine (Epi) and norepinephrine (NE) were not influenced by L-DOPA treatment, although they were elevated following the consumption of the cricket. Lizards that ingested L-DOPA treated crickets had elevated L-DOPA in all brain regions measured, with DA and/or DOPAC also increased significantly in most brain regions studied. Despite increased DA levels in the striatum and nucleus accumbens as a response to L-DOPA, the treatment had no influence on general motor activity. Central serotonin, NE, and Epi systems were not affected in any brain region by oral L-DOPA treatment. In addition, aggression was inhibited by this dose of L-DOPA, even though there was no effect on serotonergic systems. This is surprising because controlling aggressive behavior is usually considered the province of serotonergic activity. Aggression was measured before and after treatment, and while saline-treated lizards retained the full vigor of aggressive activity, those fed a cricket injected with L-DOPA were only one-third as aggressive after treatment. As L-DOPA treatment did not affect general motor activity, the effect appears to be directly associated with aggression. This is supported by the observation that L-DOPA treatment delayed latency to eyespot darkening, which predicts the latency to aggression.

Administration, Oral↗
PubMed2006

Cortisol moderates the relationship between testosterone and aggression in delinquent male adolescents.

BACKGROUND: In animals, strong evidence exists for an association between testosterone and aggression. In humans, and particularly in children and adolescents, findings have been less consistent. Previous research has suggested that this may partly be due to moderating effects of other factors, e.g., hormones. This study aims to investigate the moderating effect of cortisol on the relationship between testosterone and subtypes of aggression in delinquent male adolescents. METHODS: Participants were 103 boys (mean age 13.7) referred to a delinquency diversion program. Testosterone and cortisol levels were determined from saliva samples collected during resting conditions and related to self-report scores on overt and covert aggression. RESULTS: Linear regression analyses revealed a significant interaction between cortisol and testosterone in relation to overt aggression, with a significant positive relationship between testosterone and overt aggression in subjects with low cortisol levels but not in subjects with high cortisol levels. Using the same model for covert aggression, no significant effects of testosterone, cortisol, or testosterone x cortisol interaction were found. CONCLUSIONS: These results indicate a moderating effect of cortisol on the relationship between testosterone and overt aggression in delinquent male adolescents. Implications and directions for future research are discussed.

Adolescent↗
PubMed2006

Neurokinin-1 receptor in the basolateral nuclear group of the canine amygdala--comparative study in normal and aggressive dogs.

Substance P and its NK-1 receptor are involved in the modulation of aggressive behavior. Because of the role of the basolateral nuclear group (BNG) of the amygdala in canine aggression, neurokinin-1 receptor (NK-1) immunoreactivity in this brain region was assessed stereologically in 7 normally behaving and 6 pathologically aggressive dogs. The first aim of this study was to obtain information about the absolute number of neurons expressing the NK-1 receptor in the canine BNG because absolute numbers of neurons expressing the NK-1 receptor are not documented in literature. Additionally, an exploratory comparison was made between NK-1 expressing neurons in the BNGs of normally behaving and aggressive dogs. Results showed a very low amount (1-2%) of BNG neurons containing the NK-1 receptor in both groups. Aggressive dogs had significantly more NK-1-receptor-positive BNG neurons than normal dogs, but the numerical densities and fractions of receptor-positive neurons did not differ significantly between both groups. Combined with the fact that aggressive dogs have 27% more neurons in their BNGs than normal dogs, as reported in a previous study, these findings suggest a limited role for the NK-1-receptor-positive neurons within the BNG in the modulation of canine aggression. The present report of absolute numbers of neurons expressing the NK-1 receptor in the canine BNG could however be useful for further quantitative studies.

Aggression↗
PubMed2005

Psychiatric and behavioral problems in aggressive drivers.

Motor vehicle accidents (MVAs) are a leading cause of accidental death and injury, and aggressive driving has been identified as a risk factor for MVAs. Assessing psychiatric and behavioral disturbances in aggressive drivers is germane to the development of prevention and intervention programs for this population. The present study compared the prevalence of psychiatric diagnoses and behavioral problems in young adult drivers with self-reported high driving aggression to that of drivers with low driving aggression. Aggressive drivers evidenced a significantly higher current and lifetime prevalence of Oppositional Defiant Disorder, Alcohol and Substance Use Disorders, and Cluster B Personality Disorders, and a significantly greater lifetime prevalence of Conduct Disorder, Attention-Deficit/Hyperactivity Disorder, and Intermittent Explosive Disorder. Aggressive drivers also had a significantly greater prevalence of self-reported problems with anger, as well as a greater family history of anger problems and conflict. The findings suggest that prevention and intervention programs designed to reduce aggressive driving may need to address the presence of psychiatric and behavioral problems that could potentially complicate treatment or impede responses to treatment.

Adult↗
PubMed2005

Antidepressant treatments and human aggression.

Aggressive behaviour is associated with negative mood and poor impulse control. Serotonin has been specifically associated with impulse regulation and deficiencies in serotonin have been linked to impulsive aggression. However, aggression occurs in a social context and noradrenaline has been implicated in social motivation. Both serotonergic and noradrenergic antidepressants may therefore be effective in reducing aggression. The evidence for the effects of antidepressants on aggression comes from a wide range of sources but there are few controlled trials or experimental studies. Current findings point to decreases in negative mood and anger attacks and positive changes in personality traits after antidepressant treatment. Clinical studies in personality disorder patients have shown some efficacy for serotonergic antidepressants in reducing irritability and impulsive aggression. Experimental work in healthy volunteers has shown both serotonergic and noradrenergic antidepressants to increase assertiveness and affiliative behaviour. Both may therefore decrease aggression through different routes.

Aggression↗
PubMed2005

Violence among peoples in the light of human frustration and aggression.

This article sets out to provide a general background to the study of aggression in the social sciences, with a particular focus on its link to collective violence. While the study of what happens in the human brain appears to be already highly complex, analysis of violent behavior appears to be even more intricate. A deductive system in the sense of a general and clear system of propositions logically connected to one another is not feasible, principally because contrary to the natural sciences there are no verities but merely "stylized facts." One of these concerns the setting of human aggression in the light of frustration, as argued in the frustration-aggression hypothesis developed by Dollard et al. in 1939. Apart from conceiving of aggression as a pure human instinct, it may also be seen as externally driven, while a third possibility concerns culturally "learned" aggression. Proof of the latter is that the strongest correlation appears to be that between current violence and previous manifestations thereof. Attention is paid to the way in which Gurr has rooted his relative deprivation theory on causes of collective violence among peoples in mechanisms of frustration and aggression. That theory is taken a bit further in terms of "perceived acquirement failure," which appears to be highly connected to the role of the state. Based on certain observations by Hannah Arendt, the argument then proceeds to violence as a manifestation of powerlessness. Finally, this leads to a discussion of justice as a crucial factor in what Durkheim used to call a "right to conflict." In this way, human aggression is placed in a broad socio-economic context.

Aggression↗
PubMed2005

5-HT1B receptors and aggression: a review.

The serotonergic (5-HT) system in the brain is involved in the modulation of offensive aggressive behavior. The dogma that activity of the 5-HT system is inversely related to aggression is obsolete now. Research on the status of the 5-HT system before, during and after the execution of aggression is ongoing but has not yet led to a clear picture about the actual functional role of the 5-HT system, the more because state versus trait aggression seems to play a pivotal role in the outcome. Pharmacological challenges pinpoint 5-HT(1A) and 5-HT(1B) receptors as key players in the modulation of offensive aggression. This review emphasizes in particular the role of postsynaptic 5-HT(1B) (hetero) receptors as a premier site to modulate offensive aggression. Modulation of the firing and 5-HT release of the serotonergic neuron, via presynaptic 5-HT(1A) (auto) receptors, presynaptic 5-HT(1B) (auto) receptors and serotonergic transporters, may also have striking influences on aggression under certain conditions. Therefore, it is hypothesized that postsynaptic 5-HT(1B) (hetero) receptors directly influence the executive, consummatory phases of agonistic behavior, whereas presynaptic serotonergic feedback systems are particularly useful in the introductory (appetitive) phases of the agonistic behavioral complex.

Aggression↗
PubMed2006

The relationship between sleeping problems and aggression, anger, and impulsivity in a population of juvenile and young offenders.

PURPOSE: The current study examines both the quantity and quality of sleep reported by male adolescents detained in prison, with a focus on exploring the association between the quantity and quality of sleep with aggression, impulsivity, or anger. This represents a novel area of study not yet explored among incarcerated male adolescents. METHOD: One hundred eighty-four offenders took part; 104 young (average age 19 years) and 80 juvenile (average age 16 years). All completed a questionnaire exploring sleeping problems, and measures assessing aggression, anger, and impulsivity. RESULTS: Aggression was found to relate both to the quantity and quality of sleep reported, with reduced quantity and quality predicted by increased overall aggression. Across aggression subscales, only increased hostility was predictive of reduced current hours of sleep and increased problems in sleep quality. Apnea risk scores were not predicted by aggression, anger, or impulsivity. Differences in sleep behavior before and during prison were demonstrated, with evidence for increased poor sleeping habits within detention. No differences were observed between young and juvenile offenders. CONCLUSIONS: This study suggests a potential relationship between aggression and sleep among an incarcerated adolescent male sample, highlighting in particular a role for hostility. The findings are discussed in relationship to implications for treatment and directions for future research.

Adolescent↗
PubMed2004

Friendships of aggressive youth: considering the influences of being disliked and of being perceived as popular.

Past research provides conflicting evidence regarding whether aggressive youth have problems in the domain of friendship. The current study tested whether being disliked by peers exacerbates the negative effects of aggression on friendship and whether being perceived as popular by peers mitigates these damaging effects. Participants were 607 third-, fifth-, seventh-, and ninth-grade students. Support for the hypothesis that being disliked or being perceived as popular would moderate relations between aggression and friendship adjustment was found for the association between relational aggression and friendship conflict. Specifically, relational aggression was associated with having conflictual friendships for youth who were disliked but not for youth who were perceived as popular. In addition, similarity between friends was found in terms of how aggressive youth were as well as in terms of how disliked they were and how popular they were perceived to be. Implications for the well-being and development of aggressive youth are discussed.

Adolescent↗
PubMed2005

Deception and subtypes of aggression during early childhood.

A multi-informant study investigated the association between deception capacities and subtypes of aggression in a young early childhood sample (M = 44.65 months of age, SD = 13.39, N = 64). A newly developed teacher report of deception had appropriate psychometric properties (reliability, concurrent validity, and construct validity). Recently introduced observational methods of physical and relational aggression were reliable and valid with this sample. Findings indicated that both physical and relational aggression were associated with concurrent deception. For boys only, physical aggression uniquely predicted deception, controlling for the variance associated with relational aggression. In addition, relational aggression predicted deception above and beyond the role of physical aggression for the entire sample.

Aggression↗
PubMed2006

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.

Adult↗
PubMed2005

Ethanol exposure during development reduces resident aggression and testosterone in rats.

Ethanol exposure during development has been shown to alter social behaviors in people, but the range of deficits is not clear. Using an animal model of Fetal Alcohol Spectrum Disorders, inter-male aggression and testosterone levels were examined in adult rats. Rats were exposed to ethanol during the entire prenatal period and from postnatal day 2 through 10. Ethanol was administered via intragastric intubation. Two other groups consisted of a nontreated control and an intubated control group that was exposed to the administration procedures but not ethanol. Both offensive and defensive aggression were examined in experimental residents and intruders under three different housing conditions for the resident males: (1) with another male, (2) with a pregnant female, and (3) with a female and litter fathered by the experimental animal. When housed with a female and litter, ethanol-exposed rats displayed reduced offensive aggression compared to control groups under the same condition. Defensive aggression in the non-experimental intruders was reduced in this same condition. There were no differences in duration of non-aggressive social behaviors among the groups in any of the housing conditions. Testosterone levels were reduced in ethanol-exposed rats compared to controls. In summary, ethanol exposure over the combined prenatal and postnatal periods reduces aggressive behavior in a condition where aggressive behavior is normally seen. This reduction may be related to lower testosterone levels.

Aggression↗
PubMed2004

Electrophysiological substrates of impulsiveness: potential effects on aggressive behavior.

Previous investigations attempting to examine impulsiveness as a personality construct are likely confounded with a high incidence of aggressive and antisocial behavior. The present study assessed electroencephalographic activity at rest and during photic stimulation in two groups: (1) an impulsive group (n=10) scoring high on the Barratt Impulsiveness Scale (BIS-11) and reporting no indication of impulsive aggressive behavior; and (2) a non-aggressive control group (n=14) scoring within the normal range on the BIS-11. All subjects completed a brief battery of personality measures related to impulsivity and aggression. Resting EEG was recorded at 9 electrode sites. Photic stimulation was administered at three frequency levels. The primary findings were consistently lower frontal delta and theta activity in the impulsive group as well as a different topographical pattern of beta activity between the groups. These differences appeared to be independent of photic stimulation. Personality analyses indicated significantly greater hostility and lifetime history of aggression in the impulsive group. Taken together, the personality and EEG results suggest some similarity between the present impulsive group and research on groups regularly exhibiting premeditated aggression. These results provide unique insight into the construct of impulsivity and its role in the expression of specific subtypes of aggressive behavior.

Adult↗
PubMed2006

Effects of olanzapine on aggressiveness in heroin dependent patients.

This study compared the anti-aggressiveness effects of the atypical anti-psychotic olanzapine with that of selective serotonin reuptake inhibitors (SSRI) and benzodiazepines (BZD) among patients with heroin dependence submitted to opioid-agonists substitution treatment. Sixty-seven (67) patients who met the DSM-IV criteria for heroin dependence and showed aggressive personality traits, not affected by comorbid schizophrenia or bipolar disorder, accepted to participate in a 12-week prospective, observational trial. Patients were included into two subgroups in relationship with treatment, for the evaluation of the endpoints at week 12: group 1: substitution treatment in combination with OLA (32 patients); group 2: substitution treatment in combination with fluoxetine/paroxetine and clonazepam (35 patients). Efficacy measures were Buss Durkee Hostility Inventory (BDHI), Symptoms Check List-90 (SCL 90) anger--hostility scores, incidence rates of aggressive incidents and attacks. The rates of patients who remained in treatment at week 12 in group 1, treated with OLA, and group 2, treated with SSRI and BDZ, were not significantly different (17 = 53.1% vs 16 = 45.7%). BDHI total, direct aggressiveness, verbal aggressiveness scores, SCL 90 aggressiveness scores and aggressive incidents rates showed a significantly more consistent decrease from baseline in group 1 than in group 2 subjects, in the patients who completed the treatment (p < 0.001; p < 0.01; p < 0.05; p < 0.01; p < 0.001). Among the completers, 69.3% achieved early full substance abuse remission, while 30.7% achieved partial substance abuse remission, with no significant difference between 1 and 2 treatment subgroups. Although obtained by an observational--open clinical study, with multiple limitations, our findings suggest that OLA may be useful as an adjunctive agent in reducing aggressive/hostile behaviour in heroin addicted individuals during maintenance substitution treatment. Otherwise, atypical anti-psychotic OLA seems to be unable to improve the outcome in terms of addictive behavior and relapse risk in the addicted patients not affected by overt psychotic disorders.

Adult↗
PubMed2003

Interaction of nitric oxide and serotonin in aggressive behavior.

Nitric oxide (NO) modulates many behavioral and neuroendocrine responses. Genetic or pharmacological inhibition of the synthetic enzyme that produces NO in neurons evokes elevated and sustained aggression in male mice. Recently, the excessive aggressive and impulsive traits of neuronal NO synthase knockout (nNOS-/-) mice were shown to be caused by reductions in serotonin (5-HT) turnover and deficient 5-HT1A and 5-HT1B receptor function in brain regions regulating emotion. The consistently high levels of aggression observed in nNOS-/- mice could be reversed by 5-HT precursors and by treatment with specific 5-HT1A and 5-HT1B receptor agonists. The expression of the aggressive phenotype of nNOS-/- knockout mice requires isolated housing prior to testing. The effects of social factors such as housing condition and maternal care can affect 5-HT and aggression, but the interaction among extrinsic factors, 5-HT, NO, and aggression remains unspecified. Taken together, NO appears to play an important role in normal brain 5-HT function and may have significant implications for the treatment of psychiatric disorders characterized by aggressive and impulsive behaviors.

Aggression↗
PubMed2004

Long-term effects of pubertal anabolic-androgenic steroid exposure on reproductive and aggressive behaviors in male rats.

The current study examined acute and long-term effects of anabolic-androgenic steroid (AAS) exposure during puberty on copulation, vocalizations, scent marking, and intermale aggression, both with and without tail pinch, in intact male rats. Animals received 5 mg/kg of testosterone, nandrolone, stanozolol, or vehicle, beginning at puberty. After 5 weeks, behavior tests were performed while continuing AAS injections. AAS treatment was then discontinued. Behaviors were tested during 3-5 weeks, 9-11 weeks, and 15-17 weeks of withdrawal. During AAS administration, stanozolol males showed significant reductions in all behaviors compared with controls, except aggression with tail pinch. Nandrolone treatment significantly reduced vocalizations and scent marking, and testosterone had no significant effect on behavior. During withdrawal, behaviors in stanozolol males recovered to control levels at variable rates: aggression at 4 weeks; mounts, vocalizations, and scent marking at 9 weeks; and ejaculations at 15 weeks of withdrawal. Stanozolol males showed significantly higher levels of tail pinch-induced aggression during every withdrawal test. Nandrolone-treated males scent-marked at control levels by 9 weeks withdrawal but displayed significantly fewer vocalizations and significantly more tail pinch-induced aggression than controls for the entire study. Testosterone-treated males scent-marked significantly below controls at 3 weeks withdrawal and showed significantly more tail pinch-induced aggression at 5 weeks withdrawal. All three AAS significantly increased tail pinch-induced aggression compared with corresponding nontail pinch tests, even at study endpoint. These results suggest that alterations in androgen-dependent behaviors by pubertal AAS exposure can persist long after drug exposure, and some effects may even be permanent.

Aggression↗
PubMed2004

Effect of photoperiod on vasopressin-induced aggression in Syrian hamsters.

Syrian hamsters are photoperiodic and become sexually quiescent when exposed to short "winter-like" photoperiods. In short photoperiods, male hamsters display significantly higher levels of aggression than males housed in long photoperiods. Arginine-vasopressin (AVP) within the anterior hypothalamus (AH) has been reported to modulate aggression in hamsters housed in long photoperiods. Previous studies have shown that AVP can facilitate aggression and its effects appear to be mediated by AVP V(1a) receptors (V(1a)R). In the present study, we investigated whether the increased levels of aggression observed after exposure to short photoperiod were the result of an increased responsiveness to AVP within the AH. Injections of AVP into the AH significantly increased aggression in hamsters housed in a long photoperiod, but had no effect in hamsters housed in a short photoperiod. In addition, injection of a V(1a)R antagonist into the AH significantly inhibited aggression in hamsters housed in long photoperiod, but had no effect in hamsters housed in a short photoperiod. These findings indicate that AVP within the AH increases aggression in hamsters housed in long photoperiods, but not in hamsters housed in short photoperiods.

Aggression↗