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Animal studies suggest a causal link between testosterone and aggression. However, in human research the exact role of this hormone is still unclear, having been linked to dominance and approach behavior rather than to aggression per se. In a social context, the induction of aggression might be confounded with dominance or status changes, which potentially influence the association between aggression and testosterone. The objective of the current study was to investigate the influence of testosterone on non-social aggression in a double-blind, placebo-controlled experiment including 90 healthy male participants. To this end, we developed an innovative paradigm in which participants were provoked by a malfunctioning joystick restraining them from a promised reward. As measures for aggression throughout the task the joystick amplitude was recorded and anger was assessed via emotional self-ratings. Participants reacted to the provocation with a significant shift to more negative emotions and increased implicit aggressive behavior, reflected in the force exerted to pull the joystick following provocation. Importantly, the study demonstrated first evidence for a modulating influence of testosterone on non-social aggression in males: Self-rated anger was significantly elevated in the testosterone group compared to the placebo group as a function of provocation. Testosterone administration did not significantly influence the implicit aggressive response. These findings demonstrate a potentiating effect of testosterone on provocation-related anger in a non-social context. Furthermore, the results highlight the importance of disentangling different components of aggression and characterizing different influencing factors when inferring on hormonal effects., (Copyright © 2017 Elsevier B.V. and ECNP. All rights reserved.)

Background: Testosterone can motivate human approach and avoidance behavior. Specifically, the conscious recognition of and implicit reaction to angry facial expressions is influenced by testosterone. The study tested whether exogenous testosterone modulates the personal distance (PD) humans prefer in a social threat context., Methods: 82 healthy male participants underwent either transdermal testosterone (testosterone group) or placebo application (placebo group). Each participant performed a computerized stop-distance task before (T1) and 3.5h after (T2) treatment, during which they indicated how closely they would approach a human, animal or virtual character with varying emotional expression., Results: Men's PD towards humans and animals varied as a function of their emotional expression. In the testosterone group, a pre-post comparison indicated that the administration of 50mg testosterone was associated with a small but significant reduction of men's PD towards aggressive individuals. Men in the placebo group did not change the initially chosen PD after placebo application independent of the condition. However comparing the testosterone and placebo group after testosterone administration did not reveal significant differences. While the behavioral effect was small and only observed as within-group effect it was repeatedly and selectively shown for men's PD choices towards an angry woman, angry man and angry dog in the testosterone group. In line with the literature, our findings in young men support the influential role of exogenous testosterone on male's approach behavior during social confrontations., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Chronic methamphetamine (MA) use can lead to white matter (WM) changes and increased levels of aggression. While previous studies have examined WM abnormalities relating to cognitive impairment, associations between WM integrity and aggression in MA dependence remain unclear. Diffusion Tensor Imaging (DTI) was used to investigate WM changes in 40 individuals with MA dependence and 40 matched healthy controls. A region of interest (ROI) approach using tract based spatial statistics (TBSS) in FSL was performed. We compared fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ║) and perpendicular diffusivity (λ┴) in WM tracts of the frontal brain. A relationship of WM with aggression scores from the Buss & Perry Questionnaire was investigated. Mean scores for anger (p < 0.001), physical aggression (p = 0.032) and total aggression (p = 0.021) were significantly higher in the MA group relative to controls. ROI analysis showed increased MD (U = 439.5, p = 0.001) and λ┴ (U = 561.5, p = 0.021) values in the genu of the corpus callosum, and increased MD (U = 541.5, p = 0.012) values in the right cingulum in MA dependence. None of the WM changes were significantly associated with aggression scores. This study provides evidence of frontal WM changes and increased levels of aggression in individuals with MA dependence. The lack of significant associations between WM and aggressive behaviour may reflect methodological issues in measuring such behaviour, or may indicate that the neurobiology of aggression is not simply correlated with WM damage but is more complex.

This study draws on Finkel and Eckhardt's (2013) I³ framework to examine the interactive effects of 2 emotion regulation strategies-anger rumination (an impellance factor) and reappraisal (an inhibition factor), and alcohol intoxication (a disinhibition factor)-on intimate partner aggression (IPA) perpetration as measured with an analogue aggression task. Participants were 69 couples recruited from a large Midwestern university (total N = 138). Participants' trait rumination and reappraisal were measured by self-report. Participants were randomized individually to an alcohol or placebo condition, then recalled an anger event while using 1 of 3 randomly assigned emotion regulation conditions (rumination, reappraisal, or uninstructed). Following this, participants completed an analogue aggression task involving ostensibly assigning white noise blasts to their partner. Participants in the alcohol condition displayed greater IPA than participants in the placebo condition for provoked IPA, but not unprovoked IPA. Results also revealed interactions such that for those in the alcohol and rumination group, higher trait reappraisal was related to lower unprovoked IPA. For provoked IPA, higher trait rumination was related to greater IPA among those in the alcohol and rumination condition and those in the placebo and uninstructed condition. In general, results were consistent with I³ theory, suggesting that alcohol disinhibits, rumination impels, and trait reappraisal inhibits IPA. The theoretical and clinical implications of these findings are discussed in the context of current knowledge about the influence of alcohol intoxication and emotion regulation strategies on IPA perpetration., ((c) 2015 APA, all rights reserved).)

Objective: To report two cases of major depressive disorder in which lamotrigine (LTG) induced anger with murderous impulse., Patients: Case 1 was a 22-year-old man with symptoms of obsessive-compulsive disorder who developed major depressive disorder with antidepressant-induced hypomanic episodes. Case 2 was a 23-year-old woman experiencing an antidepressant-refractory depressive episode for whom remission was achieved by switching to a mood stabilizer and antipsychotics. In both cases LTG was started to treat the depressive episode., Results: Case 1 manifested with anger and murderous impulse when taking 125 mg/day of LTG. A reduction to 75 mg/day calmed this anger. Case 2 manifested with the same symptom when taking 25 mg/day of LTG, and the symptom immediately disappeared upon stopping LTG., Conclusions: Use of LTG for epilepsy in intellectually disabled patients was reported to be associated with onset or exacerbation of aggressive or violent behavior. The two cases would suggest that LTG may cause anger so severe as to be accompanied with murderous impulse when administered to patients with mood disorders. Physicians should be cognizant of this possible, albeit infrequent, adverse effect even in use of LTG for mood disorders., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Oxytocin has been implicated in the regulation of social as well as aggressive behaviors, and in a recent study we found that the effect of alcohol on aggressive behavior was moderated by the individual's genotype on an oxytocin receptor gene (OXTR) polymorphism (Johansson et al., 2012). In this study we wanted to deepen and expand the analysis by exploring associations between three (rs1488467, rs4564970, rs1042778) OXTR polymorphisms and aggressive behavior, trait anger as well as anger control in a population-based sample of Finnish men and women (N=3577) aged between 18 and 49 years (M=26.45 years, SD=5.02). A specific aim was to investigate if the polymorphisms would show interactive effects with alcohol consumption on aggressive behavior and trait anger, as well as to explore whether these polymorphisms affect differences in anger control between self-reported sober and intoxicated states. The results showed no main effects of the polymorphisms, however, three interactions between the polymorphisms and alcohol consumption were found. The effect of alcohol consumption on aggressive behavior was moderated by the genotype of the individual on the rs4564970 polymorphism, in line with previous results (Johansson et al., 2012). For trait anger, both the rs1488467 and the rs4564970 polymorphisms interacted with alcohol consumption. It appears that the region of the OXTR gene including both the rs4564970 and the rs1488467 polymorphisms may be involved in the regulation of the relationship between alcohol and aggressive behavior as well as between alcohol and the propensity to react to situations with elevated levels of anger., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: This investigation attempted to determine whether trait and state hostile rumination functioned as risk factors for the relation between acute alcohol intoxication and aggression., Method: Participants were 516 social drinkers (252 men and 264 women). Trait hostile rumination was assessed using Caprara's Dissipation-Rumination Scale. Following the consumption of either an alcohol or a placebo beverage, participants were tested on a laboratory task in which electric shocks were received from and administered to a fictitious opponent under the guise of a competitive reaction-time task. Aggression was operationalized as the combined mean responses for shock intensity and duration across all trials. In a subset of the sample (n = 320), state hostile rumination was assessed following the aggression task using a self-report measure., Results: As expected, both trait and state measures acted as moderators. Specifically, acute alcohol intoxication was more likely to increase aggression in persons with higher trait and state hostile rumination scores compared with their equally intoxicated lower rumination counterparts., Conclusions: This was the first investigation to demonstrate that trait or state rumination significantly heighten the risk of intoxicated aggression. We believe that hostile rumination facilitates intoxicated aggression because ruminators have difficulty diverting their attention away from anger-provoking stimuli and related thoughts, thus making violent reactions more likely. Clinical and public health interventions would benefit by developing strategies to distract ruminative attention away from violence-promoting messages, especially when persons are under the influence of alcohol.

Background: The association between serotonergic dysfunction and aggression has prompted the use of selective serotonin re-uptake inhibitors (SSRIs) as a means of controlling impulsive violent behaviour. The aim of the current study was to examine the feasibility of using an SSRI to treat impulsivity in a group of repeat violent offenders., Methods: Potential participants were recruited from three magistrates' court complexes in the Sydney metropolitan area and all had histories of violent offending (at least one prior conviction for a violent offence). Those who scored highly on the Barratt Impulsivity Scale (BIS-11), passed medical and psychiatric evaluations and consented to treatment were prescribed sertraline (Zoloft) over a three month period., Results: Thirty-four individuals commenced the trial, with 20 completing the three month intervention. Reductions were observed across a range of behavioural measures from baseline to 3 months: impulsivity (35%), irritability (45%), anger (63%), assault (51%), verbal-assault (40%), indirect-assault (63%), and depression (62%). All those who completed the three month trial requested to continue sertraline under the supervision of their own medical practitioner., Conclusion: Our findings suggest that treating impulsive violent individuals in the criminal justice system with an SSRI is a potential treatment opportunity for this population. An adequately powered randomized control trial of this intervention is warranted.

Background: Aggression is a major public health issue and is integral to several mental health disorders. Antiepileptic drugs may reduce aggression by acting on the central nervous system to reduce neuronal hyper-excitability associated with aggression., Objectives: To evaluate the efficacy of antiepileptic drugs in reducing aggression and associated impulsivity., Search Strategy: We searched CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, metaRegister of Controlled Trials (mRCT) and ClinicalTrials.gov to April 2009. We also searched Cochrane Schizophrenia Group's register of trials on aggression, National Research Record and handsearched for studies., Selection Criteria: Prospective, placebo-controlled trials of antiepileptic drugs taken regularly by individuals with recurrent aggression to reduce the frequency or intensity of aggressive outbursts., Data Collection and Analysis: Three authors independently selected studies and two authors independently extracted data. We calculated standardised mean differences (SMDs), with odds ratios (ORs) for dichotomous data., Main Results: Fourteen studies with data from 672 participants met the inclusion criteria. Five different antiepileptic drugs were examined. Sodium valproate/divalproex was superior to placebo for outpatient men with recurrent impulsive aggression, for impulsively aggressive adults with cluster B personality disorders, and for youths with conduct disorder, but not for children and adolescents with pervasive developmental disorder. Carbamazepine was superior to placebo in reducing acts of self-directed aggression in women with borderline personality disorder, but not in children with conduct disorder. Oxcarbazepine was superior to placebo for verbal aggression and aggression against objects in adult outpatients. Phenytoin was superior to placebo on the frequency of aggressive acts in male prisoners and in outpatient men including those with personality disorder, but not on the frequency of 'behavioral incidents' in delinquent boys., Authors' Conclusions: The authors consider that the body of evidence summarised in this review is insufficient to allow any firm conclusion to be drawn about the use of antiepileptic medication in the treatment of aggression and associated impulsivity. Four antiepileptics (valproate/divalproex, carbamazepine, oxcarbazepine and phenytoin) were effective, compared to placebo, in reducing aggression in at least one study, although for three drugs (valproate, carbamazepine and phenytoin) at least one other study showed no statistically significant difference between treatment and control conditions. Side effects were more commonly noted for the intervention group although adverse effects were not well reported. Absence of information does not necessarily mean that the treatment is safe, nor that the potential gains from the medication necessarily balance the risk of an adverse event occurring. Further research is needed.

A complex form of aggression, commonly expanded as 'aggressive challenging behaviour', is reported in one in four adults with intellectual disability and is often treated with antipsychotics, mood stabilizers and antidepressants. Psychological treatments, including anger and behavioural management, person-centred planning and manipulation of the environment (nidotherapy), have also been used when available but to a lesser extent. In this article, the evidence for efficacy for each intervention is examined, with data from randomized controlled trials given primacy. Very little evidence, based on limited data, can be found for the interventions of anger and behavioural management and also for the atypical antipsychotic drug, risperidone; the data available on these interventions come primarily from studies conducted in children in whom the behaviour is part of the autistic spectrum. Antipsychotic drugs, particularly the atypical group, have been the most commonly used interventions in recent years, but a recent independent randomized trial showed no benefits for either risperidone or haloperidol compared with placebo, with some evidence of a better response to placebo than either active drug in the reduction of aggression. In the light of this uncertainty, the clinician must return to the task of collecting a careful history and mental state examination, including awareness of the setting in which the behaviour is shown, which will help with diagnosis and appropriate intervention. The choice of intervention should not be a casual one and is not likely to be chosen well if the clinician relies only on standard guidelines. The paucity of randomized trial evidence is preventing progress in the treatment of persistent aggressive behaviour. On present evidence, the use of drug treatment should be much more sparing and reserved for those patients who are putting themselves and others at particular risk as a consequence of their behaviour; such treatment should be regarded as temporary and as adjunctive to other forms of management. There is an urgent need for larger, randomized studies of psychological interventions, which at present appear to have a higher benefit-risk ratio than drug treatment but that also have a poor evidence base. More care should be taken to avoid the term 'aggressive challenging behaviour' being used as a portmanteau diagnostic pseudonym when it merely represents a diverse oppositional repertoire of many aetiologies.

Objective: We previously tested topiramate, an anticonvulsant, in the treatment of aggression in men with borderline personality disorder (BPD) (Nickel M, Nickel C, Kaplan P, Lahmann C, Mühlbacher M, Tritt K, et al. Treatment of aggression with topiramate in male borderline patients: a double-blind, placebo-controlled study. Biol Psychiatry 2005;57:495-9), and found significant changes on most scales of the state-trait anger expression inventory (STAXI) and significant weight loss eight weeks later. The aim of this trial was to assess topiramate's efficacy in the long-term therapy for aggression in men with BPD., Methods: This 18-month follow-up observation, in which the previous patients (topiramate group: n=22; former placebo group: n=22) were examined bianually, was carried out., Results: According to the intent-to-treat principle, significant changes on all scales of the STAXI were observed in the subjects treated with topiramate. Additional significant weight loss was observed. All subjects tolerated topiramate relatively well., Conclusions: Topiramate appears to be an effective, relatively safe agent in the long-term treatment of patients with BPD. Mild, non-transient weight loss can be expected.

Anger and aggression are typical in borderline patients. The goal of this study was to compare the efficacy of lamotrigine versus placebo in the treatment of aggression in women meeting the criteria for borderline personality disorder (BPD). We conducted a randomized, double-blind, placebo-controlled study of lamotrigine in 24 female subjects meeting Structured Clinical Interview for DSM-IV (SCID) criteria for BPD. The subjects were randomly assigned in a 2: 1 manner ratio to lamotrigine (n = 18) or placebo (n = 9). Treatment duration was 8 weeks. Primary outcome measures were self-reported changes on the anger scales of the Trait Anger Expression Inventory (STAXI). In comparison with the placebo group, and according to the intention-to-treat principle, highly significant (p < 0.01) changes on four STAXI scales (State-Anger, Trait-Anger, Anger-Out, Anger-Control) were observed in those subjects treated with lamotrigine after 8 weeks. The only exception (p < 0.05) was found on the Anger-In scale, where a difference of only 8.5% (p < 0.2) was found. All the patients tolerated lamotrigine relatively well. Lamotrigine appears to be a safe and effective agent in the treatment of anger in women with criteria-defined BPD as defined by SCID criteria. It did not produce any clinically significant effect on body weight.

Objective: The goal of this study was to compare the efficacy and safety of topiramate versus placebo in the treatment of aggression in women who meet the criteria for borderline personality disorder., Method: We conducted a double-blind, placebo-controlled study of topiramate in 29 female subjects (response rate 93.5%) meeting SCID (Structured Clinical Interview for DSM-IV) criteria for borderline personality disorder. The subjects were randomly assigned in a 2:1 ratio to topiramate (N = 21, analysis based on N = 19) or placebo (N = 10). Treatment lasted 8 weeks (November 2003-January 2004). Primary outcome measures were self-reported changes on the anger subscales of the State-Trait Anger Expression Inventory (STAXI)., Results: Significant improvements on 4 subscales of the STAXI (state-anger, trait-anger, anger-out, anger-control) were observed in the topiramate-treated subjects after 8 weeks, in comparison with the placebo group. The difference in improvement in score between the 2 groups for state-anger, trait-anger, and anger-out ranged from 21% to 24%, and the difference for anger-control was -13%. As an exception, a difference of only 8.5% (p < .2) was found on the anger-in subscale. Significantly greater weight loss was observed in the topiramate-treated group than in those treated with placebo (difference in weight loss between the 2 groups: 2.3 kg [5.1 lb] [3.2%]; 95% CI = 1.3% to 4.4%, p < .01). All patients tolerated topiramate well., Conclusions: Topiramate appears to be a safe and effective agent in the treatment of anger in women with borderline personality disorder as defined by SCID criteria. Additionally, significant weight loss can be expected.

Background: Trait anger has been identified as a risk factor for alcohol-related aggression. However, to develop a more accurate risk profile, it is necessary to examine the interactive relations between trait anger and other key personality variables. The present study examined the influence of anger control on alcohol-related aggression., Methods: Participants were 164 social drinking men age 21-35 years old. Trait anger and anger control were assessed with the State-Trait Anger Expression Inventory (Spielberger, 1996). Following consumption of an alcoholic or placebo beverage, participants competed in an aggression paradigm in which electric shocks were received from and administered to a fictitious opponent during a competitive reaction time task. Aggression was operationalized as shock intensities administered to the opponent under conditions of low and high provocation., Results: Analyses indicated that trait anger significantly predicted aggression, but only among men who were intoxicated and reported low levels of anger control., Conclusions: The present findings suggest that anger control may be a crucial risk factor in determining whether one's anger proneness will lead to intoxicated aggression following provocation., (Copyright 2004 Research Society on Alcoholism)

Objective: The purpose of this study was to investigate the effects of affective, behavioral, and cognitive components of trait anger on alcohol-related aggression in men and women., Methods: Subjects were 300 (150 men and 150 women) healthy social drinkers between 21 and 35 years of age. Trait anger was measured using the ABC Anger Inventory. Following the consumption of either an alcohol or a placebo beverage, subjects were tested on a modified version of the Taylor Aggression Paradigm in which mild electric shocks were received from, and administered to, a fictitious opponent during a competitive task. Aggressive behavior was operationalized as the shock intensities administered to the fictitious opponent under conditions of low and high provocation., Results: Results indicated that alcohol increased aggression only for men with higher behavioral and cognitive anger scores and only for women with higher behavioral anger scores. Results also showed that when all anger components were taken into account, behavioral anger was the only factor that put one at risk for intoxicated aggression., Conclusions: Two recent studies demonstrated that the trait of "general" anger is a risk factor for intoxicated aggression (Giancola, 2002a; Parrott and Zeichner, 2002). The present investigation confirmed and extended these findings by examining the role of three different components of anger. The results highlight the fact that alcohol consumption does not increase aggression in all persons and in all situations. An important goal for future research is to identify which individual difference and contextual factors are most important in determining who will, and will not, behave in an aggressive manner when intoxicated.

Background: The purpose of this study was to investigate the influence of trait anger on alcohol-related aggression in men and women., Methods: Subjects were 204 healthy social drinkers (111 men and 93 women) between 21 and 35 years of age. Trait anger was measured using the Spielberger Trait Anger Scale. After the consumption of either an alcohol or a placebo beverage, subjects were tested on a modified version of the Taylor Aggression Paradigm in which mild electric shocks were received from and administered to a fictitious opponent during a competitive task. Aggressive behavior was operationalized as the shock intensities administered to the fictitious opponent under conditions of low and high provocation., Results: Of all of the variables, provocation was the strongest elicitor of aggression. Overall, anger was positively related to aggression for all subjects. However, the central finding of this study was that alcohol was more likely to increase aggression for persons, particularly men, with higher, as opposed to lower, levels of trait anger., Conclusions: The results show that alcohol consumption does not increase aggression for all persons and in all situations. A continuing goal for future research in this area is to identify which individual difference and which contextual factors are most important in determining who will and who will not behave in an aggressive manner when intoxicated.

To investigate (1) the effects of exogenous testosterone (T) on self- and partner-reported aggression and mood and (2) the role of trait impulsivity in the T-aggression relationship. Thirty eugonadal men with partners were randomized into two treatment groups to receive: (1) 200 mg im T enanthate weekly for 8 weeks or (2) 200 mg im sodium chloride weekly for 8 weeks. Eight hypogonadal men received 200 mg im T enanthate biweekly for 8 weeks. All groups completed a battery of behavior measures at baseline (Week 0) and at Weeks 4 and 8. Cognitive and motor impulsivity were the only predictors of self-reported total aggression (over and above age and T levels) at Weeks 0, 4, and 8. No significant changes in aggression or mood levels were found in the eugonadal-treated group. Significant reductions in negative mood (tension, anger, and fatigue) followed by an increase in vigor were found in response to T treatment in the hypogonadal group. These results demonstrate that inability to control one's behavior when such control is required by a particular situation (impulsivity) was found to significantly predict levels of aggression over and above age and T level. These data do not support the hypothesis that supraphysiological levels of T (within this range) lead to an increase in self- and partner-reported aggression or mood disturbances. Instead, for the first time, this study has identified the high level of negative affect experienced by hypogonadal patients. These findings have implications for T replacement therapy and male contraception.

Objective: According to recent theoretical models, the alcohol-aggression link is predicated on the interaction among many variables, including the drinker's personality. The few studies that investigated effects of personal dispositions on alcohol-related aggression have been inconclusive, possibly because the role of dispositions related to affect were largely ignored. As such, the purpose of this study was to investigate the interactive effect of alcohol and trait anger on physical aggression., Method: Participants were 136 male social drinkers who reported high, moderate, and low levels of trait anger and were nonrandomly assigned to an "alcohol" or "no-alcohol" control beverage group. Participants competed in an aggression paradigm in which electric shocks were received from and administered at will to a fictitious opponent during a competitive task. Shock intensity, duration, and proportion of highest shock served as indexes of aggression., Results: Intoxicated participants with moderate trait anger selected higher shock intensity and had a greater proportion of highest shock, compared with their sober counterparts. Within the alcohol group, high- and moderate-anger participants were more aggressive than low-anger participants. Intoxicated participants selected longer shock durations following both low and high provocation, and they evinced a greater increase in shock duration from low to high provocation than their sober counterparts. Independent of beverage group, men who reported a high or moderate level of trait anger displayed more aggression on all measures, compared with those who reported low anger disposition., Conclusions: The present findings suggest that individuals who report low levels of trait anger may be more resistant to the potentiating effects of alcohol on aggression and that the effects of alcohol on aggression may be most pronounced in men who have a moderate level of trait anger. Furthermore, independent of intoxication, trait anger appears to be a risk factor for physical aggression in men.

The increased abuse of anabolic androgenic steroids is a major concern because of physiological and psychological side-effects. In some individuals they induce dramatic behavioural changes such as increased aggression, anxiety and depression. The mechanisms behind these behavioural changes are still poorly understood. In order to obtain information on the brain regions affected by anabolic androgenic steroids, the distribution of neurons containing c-Fos, the protein product of the immediate early gene c-fos, and Fos-related antigens was studied following chronic treatment of guinea-pigs with a high dose of nandrolone decanoate (15 mg/kg i.m. daily for 14 days). The behaviour of the guinea-pigs was monitored for 1 h each day. Animals treated with nandrolone exhibited a significantly greater incidence of biting behaviour during the 14 day treatment period than vehicle-treated animals. A significantly greater density of c-Fos and Fos-related antigen-positive neurons was found in the central nucleus of the amygdala, and of Fos-related antigen-positive neurons in the frontal cortex, the shell of the nucleus accumbens and the supraoptic nucleus in nandrolone-treated animals than in vehicle controls. Therefore, nandrolone induced Fos in brain regions involved in stress, behavioural responses and reward. The increased Fos expression in these limbic brain regions is of particular interest in relation to the behavioural changes reported in humans who abuse anabolic androgenic steroids and the abuse potential of these drugs.

There have been numerous case studies and press reports of individuals committing acts of extreme violence while taking large doses of Anabolic-Androgenic Steroids (AAS). However, research using psychometric measures of aggression has tended to use small numbers of subjects which makes generalizing results difficult. In the current study the State Trait Anger Expression Inventory (STAXI) was administered to 50 AAS users and 40 non AAS-using control subjects. Subjects also underwent a semistructured interview focusing on AAS's effects on levels of aggression. Results showed that AAS users reported being significantly less in control of their aggression than controls. The semi-structured interview findings showed that elevations in aggression due to AAS use were reported by 60 per cent of AAS users. However, these elevations appeared more related to irritability and bad temper than acts of physical violence. The study also found that more AAS users than controls had worked as doormen/bouncers. This highlights the issue of whether AAS use causes aggression or whether aggressive individuals are attracted to AAS use. Future research should investigate this question.

Do people aggress to make themselves feel better? We adapted a procedure used by G. K. Manucia, D. J. Baumann, and R. B. Cialdini (1984), in which some participants are given a bogus mood-freezing pill that makes affect regulation efforts ineffective. In Study 1, people who had been induced to believe in the value of catharsis and venting anger responded more aggressively than did control participants to insulting criticism, but this aggression was eliminated by the mood-freezing pill. Study 2 showed similar results among people with high anger-out (i.e., expressing and venting anger) tendencies. Studies 3 and 4 provided questionnaire data consistent with these interpretations, and Study 5 replicated the findings of Studies 1 and 2 using measures more directly concerned with affect regulation. Taken together, these results suggest that many people may engage in aggression to regulate (improve) their own affective states.

Ten patients presenting agitation and anger outbursts at various stages following a severe closed head injury, were treated in a prospective open trial with carbamazepine, with doses ranging from 400 to 800 mg per day, during 8 weeks. Group analysis demonstrated a statistically significant improvement of a score made up from six target items from the neurobehavioural rating scale. Improvement mainly concerned irritability and disinhibition. A statistically significant improvement was also found with the Agitated Behaviour Scale. Social functioning, as assessed by family or staff ratings of the Katz Adjustment Scale, also significantly improved. No modification of global cognitive functioning was found with the Mini Mental Status Examination. Individual analysis demonstrated that the beneficial effect was important in five cases, moderate in three patients and negligible in two cases. It is concluded that carbamazepine might help to reduce agitated behaviour in brain-injured patients. However, response to treatment demonstrated an important inter-individual variability.

In order to investigate the link between aggression and 5-HT, we looked at effects of changes in plasma tryptophan on healthy male subjects. Twenty-four with high trait aggression (H) and 24 with low (L) drank an amino acid mixture with (T+) or without (T-) tryptophan. These caused plasma tryptophan enhancement and depletion, respectively, at 4.5 h. Group H subjects given T- became more angry, aggressive, annoyed, hostile and quarrelsome on subjective measures, whereas those given T+ responded in the opposite way. On a behavioural measure of aggression, group H subjects responded more aggressively after T- than T+. In contrast, there was no consistent effect on subjective or behavioural aggression in group L subjects. Feelings of well-being in group H were decreased by T- and increased by T+. In group L, T+ reduced feelings of well-being, possibly due to the sedative effect of tryptophan in this group, which correlated positively with plasma tryptophan concentration. Changes in plasma tryptophan are probably followed by changes in central 5-HT turnover. We conclude that, in those with pre-existing aggressive traits, acute falls in central 5-HT can cause increased subjective and objective aggression, while rises can have the opposite effect. The absence of changes in a low aggressive group suggests that the primary effect may be on impulsivity, possibly mediated by 5-HT1a receptors, expressing underlying aggressive traits. The findings on mood changes provide support for earlier reports of a lowering of mood with tryptophan depletion.

Theorists have attempted to account for the relationship between alcohol intoxication and a wide range of aggressive behaviors by ascribing alcohol-related aggression to the disinhibiting effects of alcohol and to its disruptive effects on cognitive processes. Allocation of attention and situational threat have been thought to mediate alcohol-related aggression. In the present study, 72 male social drinkers received either alcohol, a placebo, or a nonalcoholic beverage and were exposed to either threatening or nonthreatening personal information. Measuring levels and duration of aggressive responses on a Taylor-Buss aggression machine, intoxicated subjects were found to be generally more aggressive under threatening than under nonthreatening information conditions. Intoxicated subjects also reported relatively large increases in anger, depression, and tension following the aggression task, which appeared to be affected by the type of information received. These findings concur with and refine previous models suggesting that alcohol focuses the drinker's attention to salient cues in threatening circumstances, thus increasing the likelihood of aggressive behavior.

This study investigated the relationship between increased serotonin (5-hydroxytryptamine, 5HT) receptor sensitivity and human aggression. A low oral dose of meta-chlorophenylpiperazine (MCPP), a postsynaptic 5HT receptor agonist, was administered in a placebo-controlled design to depressed (n = 22) and panic disorder (n = 20) patients classified with or without signs of outwardly directed aggression, patients with a history of suicide attempts (inwardly directed aggression) (n = 11), and normal controls (n = 19). Hormones under 5HT control were measured at 30-min intervals. Results were as follows: (1) MCPP did not induce or reduce anger, (2) patients with outwardly directed aggression did not have significantly greater MCPP-induced cortisol or prolactin release than did patients without signs of outwardly directed aggression, (3) patients with a history of suicide attempts did not have significantly greater MCPP-induced cortisol or prolactin release than did normal controls, and (4) MCPP-induced hormone release was unrelated to measures of aggression.

Metoprolol, a selective beta 1-adrenoreceptor blocker, was administered to two patients with intermittent explosive disorder who had not done well with previous medications, including propranolol and carbamazepine. Both patients improved dramatically, suggesting clinical and theoretical relevance.