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PubMed1975

Effects of viewed violence and aggression: stimulation and catharsis.

Tests of the catharsis hypothesis involving viewed violence have led to conflicting results. It was suggested that the inconsistencies were due in part to the use of two different types of response measures, aggressive responses and hostile responses. This study involved a direct comparison of the two types of responses under conditions of instigation versus no instigation and aggressive versus neutral film. It was hypothesized that viewing an aggressive film would lead to a decrease in hostile responses (catharsis) and an increase in aggressive responses (stimulation) when compared with a neutral film condition. It was also hypothesized that both stimulation and catharsis effects would be enhanced under instigation conditions. A main effect of instigation was found with subjects in the instigation condition having higher scores than those in the noninstigated condition. A main effect of film was found with subjects having lower scores in the aggressive film condition than in the neutral film condition. A significant Film times Response Outlet interaction was found which offered support for the predicted catharsis effect on the hostility measure. There was no support for the predicted stimulation effect on the aggression measure. The results of the study offer support for the main thesis that in examining the effects of viewed violence, separation of hostile responses and aggressive responses is necessary for full understanding.

Abreaction↗
PubMed1975

Isolation-induced aggression in newly hatched ducklings.

Newly hatched Khaki Campbell ducklings (Anas platyrhynchos domesticus) were initially housed in pairs and subsequently transferred to isolated housing conditions. Subjects living with another bird displayed filial behavior and little aggression upon encountering another duckling in a test arena. In contrast, ducklings housed in isolation exhibited aggressive pecking in addition to filial behavior when another duckling was subsequently encountered. In Experiment 2, ducklings were housed with an imprinting object (i.e., an object that elicits attachment behavior), but they were otherwise isolated from other birds. These subjects displayed little aggression when they were subsequently reunited with a conspecific, indicating that the aggression-precluding effects of social housing are not limited to the particular social stimulus with which the ducklings are housed. In Experiment 3, ducklings were again housed with an imprinting object, but this time the object was behind glass, thereby precluding tactile contact with it. Since these birds also exhibited little aggression when reunited with a conspecific, it is apparent that visual stimulation from an imprinting object is sufficient in itself to preclude subsequent aggression. These findings suggest that stimulation that elicits attachment behavior is the critical factor mediating isolation-induced aggression.

Aggression↗
PubMed2006

Molecular analysis of flies selected for aggressive behavior.

Aggressive behavior is pervasive throughout the animal kingdom, and yet very little is known about its molecular underpinnings. To address this problem, we have developed a population-based selection procedure to increase aggression in Drosophila melanogaster. We measured changes in aggressive behavior in the selected subpopulations with a new two-male arena assay. In only ten generations of selection, the aggressive lines became markedly more aggressive than the neutral lines. After 21 generations, the fighting index increased more than 30-fold. Using microarray analysis, we identified genes with differing expression levels in the aggressive and neutral lines as candidates for this strong behavioral selection response. We tested a small set of these genes through mutant analysis and found that one significantly increased fighting frequency. These results suggest that selection for increases in aggression can be used to molecularly dissect this behavior.

Aggression↗
PubMed2002

Neural background of glucocorticoid dysfunction-induced abnormal aggression in rats: involvement of fear- and stress-related structures.

Glucocorticoid hypofunction is associated with persistent aggression in some psychologically disordered human subjects and, as reported recently, induces abnormal forms of aggression in rats. Here we report on the effects of glucocorticoid hypofunction on aggression-induced neural activation. Rats were adrenalectomized, and implanted with low-release glucocorticoid pellets. After one week recovery, they were challenged by an unfamiliar intruder in their home-cage. Neural activation was studied by c-Fos protein immunocytochemistry. Aggressive encounters in controls induced c-Fos activation in all brain areas relevant for the control of aggression (cortex, amygdala, septum, hypothalamus, periaqueductal grey and the locus coeruleus). Very intense c-Fos activation was observed in the medial amygdala, the hypothalamic attack area and the periaqueductal grey matter which constitute a downward stimulatory stream that activates attack behaviour. The experimentally induced glucocorticoid hypofunction dramatically increased attacks targeted towards vulnerable parts of the opponent's body (mainly the head). This abnormal behaviour was not associated with changes in the activation of brain centres involved in the control of aggression. However, the activation of brain centres involved in both the stress response (the parvocellular part of the hypothalamic paraventricular nucleus) and fear reactions (central amygdala) were markedly increased. An acute glucocorticoid treatment abolished both behavioural and neural consequences of glucocorticoid hypofunction. Our data suggest that glucocorticoid hypofunction-induced abnormal forms of aggressiveness are related to increased sensitivity to stressors and fear-eliciting stimuli. This assumption is supported by the finding that fearful situations induce attack patterns in intact rats that are similar to those induced by glucocorticoid hypofunction.

Adrenalectomy↗
PubMed1997

Aggression in clinical settings: nurses' views.

Although much has been written about 'aggression' from a variety of viewpoints, little systematic information has been gathered about what nurses see as 'aggression'. Also, it is not clear from previous reports just how important horizontal violence is for nurses compared with the other "aggressions' encountered at work. A qualitative approach was adopted as this was an initial exploratory study to describe nurses' views regarding the nature and extent of aggression in the clinical setting. A total of 29 nurses were interviewed. Findings indicate that nurses are most concerned about their colleagues' aggression towards them. Colleague abuse ranged from non-verbal innuendo to physical assault. Nurse managers were criticized for failing to implement supportive structures when aggression did arise (from colleagues or others) or to take appropriate action to prevent its recurrence. On a practical level much of the aggression reported can be seen as a breakdown in 'relationship rules', i.e. staff failed to respect each other's privacy, were unwilling to help out, keep confidences and so on.

Aggression↗
PubMed2002

A review of the assessment and treatment of anger and aggression in offenders with intellectual disability.

Rates of aggression amongst people with intellectual disability (ID) have been found to be high in studies conducted on several continents across a number of service settings. Aggression is the primary reason for people with ID to be admitted or re-admitted to institutional settings, and it is also the main reason for individuals in this client group to be prescribed behaviour-control drugs. Anger is a significant activator of aggression, but little is known about the emotional aspects of the lives of people with ID. There are many reasons for this, but a lack of reliable and validated assessment measures is chief among them. The present review found that very little work has been conducted to date concerning the development of robust tools for assessing anger and aggression in this population. A narrative review of interventions for reducing aggression and anger in people with ID showed that there is virtually no evidence to support the use of psychotropic medications. Research has shown that behavioural interventions can be effective; however, they are intrusive and have not been tested in naturalistic settings with higher-functioning clients and low-frequency aggression. More recently, cognitive-behavioural interventions have shown promise, but the mechanisms for effective change have yet to be delineated. Priority research questions relating to assessment, treatment and therapeutic skills in working with anger and aggression problems are offered by the present review.

Aggression↗
PubMed2002

Responses of staff towards people with mild to moderate intellectual disability who behave aggressively: a cognitive emotional analysis.

BACKGROUND: Traditionally, research into interactions between staff and adults with an intellectual disability who engage in challenging behaviour has been carried out within a behavioural paradigm. Recent work has begun to examine cognitive factors. The majority of this research has drawn upon Weiner's attributional model of helping behaviour. Moreover, staff responses have usually been investigated in relation to client vignettes of challenging behaviour. METHOD: The present study involved 38 staff who worked with frequently aggressive clients and its aims were twofold: (1) to compare different methods of examining the cognitive and emotional responses of staff to aggression; namely, descriptive vignettes and real incidents of aggression which staff could recall; and (2) to attempt to replicate previous findings supportive of Weiner's model with a new carer group (day centre staff). RESULTS: When staff responses were compared across the hypothetical and real scenarios, using a series of one-way analyses of variance, it was revealed that staff experienced more negative emotions in response to the real incidents of aggression. The present study produced little evidence in support of Weiner's model. However, it was found that staff perceptions of the aggressive clients were linked to their cognitive and emotional responses to the aggression. CONCLUSION: The theoretical and clinical implications of these findings are considered, and the possible role played by interpersonal attributions in mediating staff responses to aggression is discussed.

Adult↗
PubMed1999

An exploratory account of registered nurses' experience of patient aggression in both mental health and general nursing settings.

Until relatively recently, aggression and violence in nursing has been an area of little discussion (Poster & Ryan 1993). Today, concerns are rising about escalating levels of violence towards nurses (Wykes 1994, Whittington 1997). In response, this paper explores registered nurses' experiences of patient aggression encountered in the acute inpatient general and mental health settings. Critical incidents from registered nurses in both areas are examined and analyzed in relation to existing literature. The aim of the research is to ascertain if differences exist or similarities prevail. Findings reveal that the two areas have similar problems in terms of types of aggression. Verbal and 'minor' types of aggression are the most problematic. Also, the 'biomedical model' of care is evident in both settings and possibly underpins chosen approaches to aggression management. The repeated use of chemical and physical restraint is apparent. The main comparison identified between the two groups relates to nursing control over situations involving violent patients. Mental health nurses seem to consistently take control of aggressive situations whilst general nurses tend to rely more heavily upon the input of others (medical staff, mental health teams and the police) when intervening. These two nursing specialties therefore have much to learn from each other in terms of nursing experience and possible future approaches to the management of aggressive patients.

Aggression↗
PubMed2003

Accumbal dopamine and serotonin in anticipation of the next aggressive episode in rats.

Autonomic and limbic neural activities are linked to aggressive behavior, and it is hypothesized that activities in the cardiovascular and monoaminergic systems play a role in preparing for an aggressive challenge. The objective was to learn about the emergence of monoamine activity in nucleus accumbens before an aggressive confrontation that was omitted at the regular time of occurrence, dissociating the motoric from the aminergic activity. Dopamine, serotonin, heart rate and behavioral activity were monitored before, during and after a single 10-min confrontation in resident male Long-Evans rats fitted with a microdialysis probe in the n. accumbens and with a telemetry sender (experiment 1). DA, but not 5-HT efflux, was confirmed to increase in n. accumbens during and after a single aggressive episode. In aggressive males that confronted an opponent daily for 10 days (experiment 2) heart rate rose 1 h before the regularly scheduled encounter relative to control rats, as measured on day 11 in the absence of any aggression. Concurrently, DA levels increased by 60-70% over baseline levels and 5-HT levels decreased by 30-35% compared to baseline levels. These changes were sustained over 1 h, and contrasted with no significant changes in DA, 5-HT, heart rate or behavioral activity in control rats. The rise in mesolimbic DA appears to be significant in anticipating the physiological and behavioral demands of an aggressive episode, and the fall in 5-HT in its termination, dissociated from the actual execution of the behavior.

Aggression↗
PubMedDate not supplied

Impulsive personality traits in male pedophiles versus healthy controls: is pedophilia an impulsive-aggressive disorder?

Pedophilia is characterized by sexual attraction to prepubescent children. Despite the extensive literature documenting the pervasive and pernicious effects of childhood sexual abuse, there is surprisingly little psychiatric literature on pedophilia and its etiology remains enigmatic. In recent years, the psychiatric literature on the phenomenology, neurobiology, and treatment of impulsive-aggressive disorders has grown significantly. As some investigators have conceptualized pedophilia as an impulsive-aggressive disorder, it is of interest whether recent advances in the study of impulsive-aggressive disorders might shed light on pathological mechanisms underlying pedophilia. In the following study, 20 male subjects with a DSM-IV diagnosis of pedophilia, heterosexual type were recruited from an outpatient facility for sexual offenders and compared to 24 demographically similar control subjects. Groups were compared on three personality instruments--the Millon Clinical Multiaxial Inventory-II (MCMI-II), the Temperament and Character Inventory (TCI), and the Dimensional Assessment of Personality Impairment-Questionnaire (DAPI-Q)--to assess for select impairment in impulsive-aggressive personality traits. Pedophiles showed severe and pervasive personality impairment relative to controls. Although there was evidence of impulsivity, the findings do not suggest a predominance of impulsive-aggressive traits, and in fact provide evidence of inhibition, passive-aggression, and harm avoidance. The notion of "compulsive-aggression" in pedophilia is proposed.

Adolescent↗
PubMed1995

Effects of fluoxetine on aggressive behavior of adult inpatients with mental retardation and epilepsy.

Nineteen mentally retarded inpatients with epilepsy and a history of current or recent aggressive behavior were treated with 20 mg of fluoxetine daily. All were concurrently taking other psychotropic medications, including carbamazepine and neuroleptics. A standardized rating scale (MOAS) was used to assess the effects of fluoxetine on aggressive behavior. There were wide individual differences in drug response. In nine patients, fluoxetine treatment was associated with increased aggression, while drug withdrawal led to a decrease to below pretreatment levels. Two hypotheses concerning the apparent association between fluoxetine and increased aggression are discussed: 1) adverse effects secondary to either drug interaction or fluoxetine overmedication; and 2) a specific serotonergically mediated effect on the regulation of aggression. This study suggests that the clinician who treats mentally retarded patients with impulsive aggressive behavior should remain aware that fluoxetine may have diverse effects on aggression that vary over time and interindividually.

Adult↗
PubMed2003

In socially isolated mice, the reversal of brain allopregnanolone down-regulation mediates the anti-aggressive action of fluoxetine.

Social isolation (SI) of male mice lasting >4 weeks is associated with aggression toward intruders and a down-regulation of brain allopregnanolone (Allo) content. SI of female mice fails to down-regulate brain Allo content or to induce aggressiveness. Fluoxetine (Prozac in clinical use) is an S- and R-fluoxetine (FLX) mixture, which in mammals is metabolized into S- and R-norfluoxetine (NFLX). The S isomers of FLX and NFLX are more active than their respective R isomers in normalizing brain Allo down-regulation and in reducing the aggressiveness induced by SI. Thus, FLX stereospecifically reduces brain Allo down-regulation and the aggressiveness induced by SI, whereas serotonin (5-HT) uptake inhibition lacks stereospecificity. The doses of S-FLX and S-NFLX that reduce aggressiveness and Allo brain content down-regulation induced by SI are at least one order of magnitude lower than the doses that block 5-HT reuptake. Doses of imipramine that inhibit 5-HT uptake neither reduce aggressiveness nor normalize brain Allo down-regulation. We conclude that Allo brain content normalization is a better candidate than 5-HT reuptake inhibition to explain the reduction of aggressiveness elicited by S-FLX and S-NFLX.

Aggression↗
PubMed1977

Verbal aggression as a function of sex of subject and sex of target.

This experiment raised the question of whether previously reported sex differences in physical aggression also hold for verbal aggression. It was hypothesized that verbal aggression would be a function of sex of the object of aggression but not of the sex of the aggressor. Eighty male and female American college students gave messages which varied in degree of hostile content to either a male or female confederate (C). As predicted, verbral aggression was a function of sex of target but not of S. Verbal aggression was inhibited only toward the female C when the S was not provoked by the C; when provoked, however, Ss displayed the same level of verbal aggression toward female and male targets.

Aggression↗
PubMed2002

Aggressive behaviour observed within a neurobehavioural rehabilitation service: utility of the OAS-MNR in clinical audit and applied research.

The Overt Aggression Scale-Modified for Neurorehabilitation (OAS-MNR) has been proposed as a means of standardizing descriptions of post-acute aggressive behaviour disorders amongst people with acquired brain injury. Single cases in the literature have illustrated its clinical utility. In this paper, its contribution to clinical audit and applied research is explored. The scale was used to record all aggressive behaviour exhibited by 46 patients participating in a neurobehavioural programme during a 14 day period. Data for 3914 acts of aggression were captured. Whilst most was verbal, 443 comprised physical assaults on others. Results suggest the OAS-MNR can be usefully employed to audit practice, and has a role to play in resource allocation: however, efficacy remains best judged at the single case level. Regarding clinical research, it was found that patients with low language function were more likely to physically assault others in the absence of identifiable antecedents. Furthermore, this was more severe and required more intrusive interventions to manage it than aggression shown by the same patients which had identifiable antecedents, or any aggression exhibited by patients whose language was better preserved. It is argued that poor language function creates significant barriers to the treatment of aggression, and, whilst intervention methods with good outcome have previously been described, these are no longer routinely available in the UK. An appeal to reverse this is made.

Adolescent↗
PubMed2004

Measuring the relationship between overt aggression and expectations: a methodology for determining clinical outcomes.

The presence of aggressive behaviour following traumatic brain injury imposes special challenges within rehabilitation centres. Survivors of traumatic brain injury constitute a heterogeneous population amongst whom problems with increased irritability and aggression are characteristic. There is a clear need to determine what treatment approaches might be helpful in reducing aggressive behaviour. Whilst single-case experimental methodologies including reversal and multiple baseline designs seem ideal for this purpose, the compelling need to minimize risk can compromise their deployment, especially when aggression takes the form of physical assaults on others. When this is the case, there are difficulties in assessing whether a change in aggressive behaviour represents a successful response to treatment or is simply a function of reduced demand in the environment. The contributions made to understanding the relationship between aggression and expectations made on patients participating within rehabilitation will be explored here. A possible means of quantifying demands using the Neurobehavioural Expectations Scale will be described. Three case studies are presented that suggest that a methodology that employs concurrent use of this tool with the Overt Aggression Scale -- Modified for Neurorehabilitation, can enable objective evaluation to be made of the effects of rehabilitation on behaviour, without increasing risk.

Activities of Daily Living↗
PubMed1999

Reduction of severe aggressive behaviour in acquired brain injury: case studies illustrating clinical use of the OAS-MNR in the management of challenging behaviours.

Challenging behaviour, especially when this takes the form of aggression, may impede or prevent progress in neurorehabilitation. Despite its prevalence, the literature on management of aggression after brain injury is not extensive. It has been suggested that the 'Overt Aggression Scale-Modified for Neurorehabilitation' (OAS-MNR) could be used to help standardize future studies of aggressive behaviour. It was also suggested that this scale has sufficient properties to be useful in clinical work. In this paper, three case studies are described which attempt to illustrate the potential value of the OAS-MNR in neurorehabilitation. The use of the scale also provides evidence relating to the continued efficacy of the neurobehavioural model. In the first study, two cases are described in which reduction in aggression occurred through participation in individualized, needs-led holistic treatment programmes, which incorporated multiple interventions. These were based on neurobehavioural principles. In the second study, a further single case was presented which illustrated how the scale may be used to generate hypotheses regarding aggressive behaviour and to drive treatment. Causation and maintenance of aggression are discussed, especially with regard to cognitive impairment. Finally, practical points relating to the use of the OAS-MNR in clinical practice are reviewed.

Adult↗
PubMedDate not supplied

Relationships between aggression and pubertal increases in testosterone: a panel analysis of adolescent males.

Existing data linking testosterone (T) and aggression in human adult males are surprisingly tenuous. In one of the few studies based on adolescent males, Olweus et al. (1988) demonstrated strong relationships between concurrent measures of T and aggression. However, the conclusions that could be drawn regarding developmental change were limited. Using data from a three-year panel study of 100 adolescent males (ages 12 to 13 at study entry), we examined whether there are significant relationships between concurrently collected measures of T and self-ratings of aggression, and whether the dramatic pubertal rise in T predicts subsequent change in aggression ratings. Panel analyses incorporating concurrent, lagged, and change measures found few significant relationships between aggression and T or pubertal development. The general absence of T/aggression relationships is discussed in the context of other empirical findings, the aggression measures used, and prepubertal differentiation on aggression.

Adolescent↗
PubMed2006

The appeal of violent video games to lower educated aggressive adolescent boys from two countries.

The objective of this study was to test the effect of individual differences on appeal and use of video games. Participants were 299 adolescent boys from lower and higher secondary schools in the Netherlands and Belgium. In general, boys were most attracted to violent video games. Boys that scored higher in trait aggressiveness and lower in empathy were especially attracted to violent games and spent more time playing video games than did boys lower in trait aggressiveness. Lower educated boys showed more appreciation for both violent and nonviolent games and spent more time playing them than did higher educated boys. The present study showed that aggressive and less empathic boys were most attracted to violent games. The fact that heavy users of violent games show less empathy and higher aggressiveness suggests the possibility of desensitization. Other studies have shown that playing violent games increases aggressiveness and decreases empathy. These results combined suggest the possibility of a violence cycle. Aggressive individuals are attracted to violent games. Playing violent games increases aggressiveness and decreases empathy, which in turn leads to increased appreciation and use of violent games.

Adolescent↗