Corticolimbic function in impulsive aggressive behavior

Self-harm and suicidal acts: a suitable case for treatment of impulsivity-driven behaviour with repetitive transcranial magnetic stimulation (rTMS)

SUMMARY

Suicidal thinking, self-harm and suicidal acts are common, although determining their precise prevalence is complex. Epidemiological work has identified a number of associated demographic and clinical factors, though, with the exception of past acts of self-harm, these are non-specific and weak future predictors. There is a critical need shift focus from managing 'suicidality-by-proxy' through general mental health treatments, to better understand the neuropsychology and neurophysiology of such behaviour to guide targeted interventions. The model of the cognitive control of emotion (MCCE) offers such a paradigm, with an underlying pan-diagnostic pathophysiology of a hypoactive prefrontal cortex failing to suitably inhibit an overactive threat-responding limbic system. The result is a phenotype - from any number of causative gene-environment interactions - primed to impulsively self-harm. We argue that such neural dysconnectivity is open to potential therapeutic modification from repetitive transcranial magnetic stimulation (rTMS). The current evidence base for this is undoubtedly extremely limited, but the societal and clinical burden self-harm and suicide pose warrants such investigation.

DECLARATION OF INTEREST

K.B. is the Editor of BJPsych Open, but had no editorial involvement in the review or decision process regarding this paper.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Serotonin and impulsive aggression

Aggression is a behavior with evolutionary origins, but is often both destructive and maladaptive in today's society. Research over the past several decades has confirmed the involvement of neurotransmitter function in aggressive behavior. This research has centered around the "serotonin hypothesis." As this literature continues to grow, guided by pre-clinical research and aided by the application of increasingly sophisticated neuroimaging methodology, a more complex picture has emerged. As current pharmacological and therapeutic interventions are effective but imperfect, it is hoped that new insights into the neurobiology of aggression will reveal novel avenues for treatment of this destructive and costly behavior.

Maladaptive social information processing in childhood predicts young men's atypical amygdala reactivity to threat

BACKGROUND

Maladaptive social information processing, such as hostile attributional bias and aggressive response generation, is associated with childhood maladjustment. Although social information processing problems are correlated with heightened physiological responses to social threat, few studies have examined their associations with neural threat circuitry, specifically amygdala activation to social threat.

METHODS

A cohort of 310 boys participated in an ongoing longitudinal study and completed questionnaires and laboratory tasks assessing their social and cognitive characteristics the boys were between 10 and 12 years of age. At age 20, 178 of these young men underwent functional magnetic resonance imaging and a social threat task. At age 22, adult criminal arrest records and self-reports of impulsiveness were obtained.

RESULTS

Path models indicated that maladaptive social information-processing at ages 10 and 11 predicted increased left amygdala reactivity to fear faces, an ambiguous threat, at age 20 while accounting for childhood antisocial behavior, empathy, IQ, and socioeconomic status. Exploratory analyses indicated that aggressive response generation - the tendency to respond to threat with reactive aggression - predicted left amygdala reactivity to fear faces and was concurrently associated with empathy, antisocial behavior, and hostile attributional bias, whereas hostile attributional bias correlated with IQ. Although unrelated to social information-processing problems, bilateral amygdala reactivity to anger faces at age 20 was unexpectedly predicted by low IQ at age 11. Amygdala activation did not mediate associations between social information processing and number of criminal arrests, but both impulsiveness at age 22 and arrests were correlated with right amygdala reactivity to anger facial expressions at age 20.

CONCLUSIONS

Childhood social information processing and IQ predicted young men's amygdala response to threat a decade later, which suggests that childhood social-cognitive characteristics are associated with the development of neural threat processing and adult adjustment.

Comorbid anxiety and social avoidance in treatment of severe childhood aggression: response to adding risperidone to stimulant and parent training; mediation of disruptive symptom response

OBJECTIVE

In the four-site Treatment of Severe Childhood Aggression (TOSCA) study, addition of risperidone to stimulant and parent training moderately improved parent-rated disruptive behavior disorder (DBD) symptoms. This secondary study explores outcomes other than DBD and attention-deficit/hyperactivity disorder (ADHD) as measured by the Child and Adolescent Symptom Inventory-4R (CASI-4R).

METHODS

A total of 168 children ages 6-12 with severe aggression (physical harm), DBD, and ADHD were randomized to parent training plus stimulant plus placebo (basic treatment) or parent training plus stimulant plus risperidone (augmented treatment) for 9 weeks. All received only parent training plus stimulant for the first 3 weeks, then those with room for improvement received a second drug (placebo or risperidone) for 6 weeks. CASI-4R category item means at baseline and week 9 were entered into linear mixed-effects models for repeated measures to evaluate group differences in changes. Mediation of the primary DBD outcome was explored.

RESULTS

Parent ratings were nonsignificant with small/negligible effects, but teacher ratings (n=46 with complete data) showed significant augmented treatment advantage for symptoms of anxiety (p=0.013, d=0.71), schizophrenia spectrum (p=0.017, d=0.45), and impairment in these domains (p=0.02, d=0.26), all remaining significant after false discovery rate correction for multiple tests. Improvement in teacher-rated anxiety significantly (p=0.001) mediated the effect of risperidone augmentation on the primary outcome, the Disruptive-total of the parent-rated Nisonger Child Behavior Rating Form.

CONCLUSIONS

Addition of risperidone to parent training plus stimulant improves not only parent-rated DBD as previously reported, but also teacher-rated anxiety-social avoidance. Improvement in anxiety mediates improvement in DBD, suggesting anxiety-driven fight-or-flight disruptive behavior with aggression, with implications for potential treatment strategies. Clinicians should attend to possible anxiety in children presenting with aggression and DBD.

CLINICAL TRIAL REGISTRY

Treatment of Severe Childhood Aggression (The TOSCA Study). NCT00796302. clinicaltrials.gov.

Endocannabinoids and striatal function: implications for addiction-related behaviours

Since the identification and cloning of the major cannabinoid receptor expressed in the brain almost 25 years ago research has highlighted the potential of drugs that target the endocannabinoid system for treating addiction. The endocannabinoids, anandamide and 2-arachidonoyl glycerol, are lipid-derived metabolites found in abundance in the basal ganglia and other brain areas innervated by the mesocorticolimbic dopamine systems. Cannabinoid CB1 receptor antagonists/inverse agonists reduce reinstatement of responding for cocaine, alcohol and opiates in rodents. However, compounds acting on the endocannabinoid system may have broader application in treating drug addiction by ameliorating associated traits and symptoms such as impulsivity and anxiety that perpetuate drug use and interfere with rehabilitation. As a trait, impulsivity is known to predispose to addiction and facilitate the emergence of addiction to stimulant drugs. In contrast, anxiety and elevated stress responses accompany extended drug use and may underlie the persistence of drug intake in dependent individuals. In this article we integrate and discuss recent findings in rodents showing selective pharmacological modulation of impulsivity and anxiety by cannabinoid agents. We highlight the potential of selective inhibitors of endocannabinoid metabolism, directed at fatty acid amide hydrolase and monoacylglycerol lipase, to reduce anxiety and stress responses, and discuss novel mechanisms underlying the modulation of the endocannabinoid system, including the attenuation of impulsivity, anxiety, and drug reward by selective CB2 receptor agonists.

Emotional intelligence and impulsive aggression in Intermittent Explosive Disorder

Emotional intelligence (EI) relates to one's ability to recognize and understand emotional information and then, to use it for planning and self-management. Given evidence of abnormalities of emotional processing in impulsively aggressive individuals, we hypothesized that EI would be reduced in subjects with Intermittent Explosive Disorder (IED: n = 43) compared with healthy (n = 44) and psychiatric (n = 44) controls. The Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) was used to assess both Experiential EI and Strategic EI. Strategic, but not Experiential, EI was lower in IED compared with control subjects. These differences were not accounted for demographic characteristics, cognitive intelligence, or the presence of clinical syndromes or personality disorder. In contrast, the relationship between IED and Strategic EI was fully accounted for by a dimension of hostile cognition defined by hostile attribution and hostile automatic thoughts. Interventions targeted at improving Strategic EI and reducing hostile cognition will be key to reducing aggressive behavior in individuals with IED.

Gender differences in aggression of borderline personality disorder

Aggression is a core feature of borderline personality disorder (BPD). Well-replicated results from the general population indicate that men engage in aggression more frequently than women. This article addresses the question of whether gender also influences aggression in BPD, and whether the neurobiological mechanisms underlying aggressive behavior differ between male and female BPD patients. Data show that most self-reports, interviews and behavioral tasks investigating samples of BPD patients do not find enhanced aggressiveness in male patients, suggesting that BPD attenuates rather than aggravates gender differences usually present in the general population. Neurobiological studies comparing BPD patients with gender-matched healthy controls, however, reveal a number of interesting gender differences: On the one hand, there are well-replicated findings of reduced amygdala and hippocampal gray matter volumes in female BPD patients, while these findings are not shared by male patients with BPD. On the other hand, only male BPD patients exhibit reduced gray matter volume of the anterior cingulate cortex, increased gray matter volume of the putamen, reduced striatal activity during an aggression task, and a more pronounced deficit in central serotonergic responsivity. These neurobiological findings point to a particular importance of impulsivity for the aggression of male BPD patients. Limitations include the need to control for confounding influences of comorbidities, particularly as male BPD patients have been consistently found to show higher percentages of aggression-predisposing comorbid disorders, such as antisocial personality disorder, than female BPD patients. In the future, studies which include systematic comparisons between females and males are warranted in order to disentangle gender differences in aggression of BPD patients with the aim of establishing gender-sensitive treatments where needed.

Social neuroendocrinology of human aggression: examining the role of competition-induced testosterone dynamics

A large body of evidence indicates that individual differences in baseline concentrations of testosterone (T) are only weakly correlated with human aggression. Importantly, T concentrations are not static, but rather fluctuate rapidly in the context of competitive interactions, suggesting that acute fluctuations in T may be more relevant for our understanding of the neuroendocrine mechanisms underlying variability in human aggression. In this paper, we provide an overview of the literature on T and human competition, with a primary focus on the role of competition-induced T dynamics in the modulation of human aggression. In addition, we discuss potential neural mechanisms underlying the effect of T dynamics on human aggression. Finally, we highlight several challenges for the field of social neuroendocrinology and discuss areas of research that may enhance our understanding of the complex bi-directional relationship between T and human social behavior.

Short fused? associations between white matter connections, sex steroids, and aggression across adolescence

Functional neuroimaging studies in adults show that aggression involves reduced brain communication between subcortical and cortical areas dedicated to motivation and control, respectively. Prior research indicates that sex steroid hormone production during adolescence negatively influences the rapid development of white matter connectivity between subcortical and cortical areas during adolescence and may potentiate aggression. Here, we tested this hypothesis in 258 participants between 8 and 25 years of age by using Diffusion Weighted Imaging to examine the microstructure of white matter connections within the fronto-temporal-subcortical network. Trait aggression was measured using the Buss Perry Aggression Questionnaire and testosterone and estradiol levels were measured in saliva. Results indicated that higher levels of testosterone were associated with less white matter integrity within the fronto-temporal-subcortical network (i.e., higher mean diffusivity [MD] longitudinal [LD], and radial diffusivity [RD]). Furthermore, lower fractional anisotropy and higher MD, LD, and RD values within this network increased expressive forms of aggression and reduced inhibited forms of aggression (hostility). Our study indicates higher levels of testosterone relating to lower quality of structural cortical-subcortical connectivity, arguably resulting in a shift from inhibited towards expressive forms of aggression. Our data adds evidence to the idea that aggressive tendencies are subcortically driven, but individuals with relatively high testosterone might have lower structural connectivity within cortical control areas, resulting in a stronger tendency to act on these aggressive tendencies.

Treating the violent patient with psychosis or impulsivity utilizing antipsychotic polypharmacy and high-dose monotherapy

Insufficient treatment of psychosis often manifests as violent and aggressive behaviors that are dangerous to the patient and others, and that warrant treatment strategies which are not considered first-line, evidence-based practices. Such treatment strategies include both antipsychotic polypharmacy (simultaneous use of 2 antipsychotics) and high-dose antipsychotic monotherapy. Here we discuss the hypothesized neurobiological substrates of various types of violence and aggression, as well as providing arguments for the use of antipsychotic polypharmacy and high-dose monotherapy to target dysfunctional neurocircuitry in the subpopulation of patients that is treatment-resistant, violent, and aggressive. In this review, we focus primarily on the data supporting the use of second-generation, atypical antipsychotics both at high doses and in combination with other antipsychotics.

Effects of adverse early-life events on aggression and anti-social behaviours in animals and humans

We review the impact of early adversities on the development of violence and antisocial behaviour in humans, and present three aetiological animal models of escalated rodent aggression, each disentangling the consequences of one particular adverse early-life factor. A review of the human data, as well as those obtained with the animal models of repeated maternal separation, post-weaning social isolation and peripubertal stress, clearly shows that adverse developmental conditions strongly affect aggressive behaviour displayed in adulthood, the emotional responses to social challenges and the neuronal mechanisms activated by conflict. Although similarities between models are evident, important differences were also noted, demonstrating that the behavioural, emotional and neuronal consequences of early adversities are to a large extent dependent on aetiological factors. These findings support recent theories on human aggression, which suggest that particular developmental trajectories lead to specific forms of aggressive behaviour and brain dysfunctions. However, dissecting the roles of particular aetiological factors in humans is difficult because these occur in various combinations; in addition, the neuroscientific tools employed in humans still lack the depth of analysis of those used in animal research. We suggest that the analytical approach of the rodent models presented here may be successfully used to complement human findings and to develop integrative models of the complex relationship between early adversity, brain development and aggressive behaviour.

Deconstructing violence as a medical syndrome: mapping psychotic, impulsive, and predatory subtypes to malfunctioning brain circuits

Violence is a major management issue for forensic mental health systems. Violence can be approached as a medical syndrome and deconstructed into psychotic, impulsive, and predatory subtypes, which are hypothetically mapped onto corresponding malfunctioning brain circuits. Rational management of violence balances treatment with security, while targeting each subtype of violence with approaches unique to the psychotic, impulsive, and predatory forms of violence.

The aggression and behavioral abnormalities associated with monoamine oxidase A deficiency are rescued by acute inhibition of serotonin reuptake

The termination of serotonin (5-hydroxytryptamine, 5-HT) neurotransmission is regulated by its uptake by the 5-HT transporter (5-HTT), as well as its degradation by monoamine oxidase (MAO)-A. MAO-A deficiency results in a wide set of behavioral alterations, including perseverative behaviors and social deficits. These anomalies are likely related to 5-HTergic homeostatic imbalances; however, the role of 5-HTT in these abnormalities remains unclear. To ascertain the role of 5-HTT in the behavioral anomalies associated to MAO-A deficiency, we tested the behavioral effects of its blocker fluoxetine on perseverative, social and aggressive behaviors in transgenic animals with hypomorphic or null-allele MAO-A mutations. Acute treatment with the 5-HTT blocker fluoxetine (10 mg/kg, i.p.) reduced aggressive behavior in MAO-A knockout (KO) mice and social deficits in hypomorphic MAO-A(Neo) mice. Furthermore, this treatment also reduced perseverative responses (including marble burying and water mist-induced grooming) in both MAO-A mutant genotypes. Both MAO-A mutant lines displayed significant reductions in 5-HTT expression across the prefrontal cortex, amygdala and striatum, as quantified by immunohistochemical detection; however, the down-regulation of 5-HTT in MAO-A(Neo) mice was more pervasive and widespread than in their KO counterparts, possibly indicating a greater ability of the hypomorphic line to enact compensatory mechanisms with respect to 5-HT homeostasis. Collectively, these findings suggest that the behavioral deficits associated with low MAO-A activity may reflect developmental alterations of 5-HTT within 5-HTergic neurons. Furthermore, the translational implications of our results highlight 5-HT reuptake inhibition as an interesting approach for the control of aggressive outbursts in MAO-A deficient individuals.

Talking in Fury: The Cortico-Subcortical Network Underlying Angry Vocalizations

Although the neural basis for the perception of vocal emotions has been described extensively, the neural basis for the expression of vocal emotions is almost unknown. Here, we asked participants both to repeat and to express high-arousing angry vocalizations to command (i.e., evoked expressions). First, repeated expressions elicited activity in the left middle superior temporal gyrus (STG), pointing to a short auditory memory trace for the repetition of vocal expressions. Evoked expressions activated the left hippocampus, suggesting the retrieval of long-term stored scripts. Secondly, angry compared with neutral expressions elicited activity in the inferior frontal cortex IFC and the dorsal basal ganglia (BG), specifically during evoked expressions. Angry expressions also activated the amygdala and anterior cingulate cortex (ACC), and the latter correlated with pupil size as an indicator of bodily arousal during emotional output behavior. Though uncorrelated, both ACC activity and pupil diameter were also increased during repetition trials indicating increased control demands during the more constraint production type of precisely repeating prosodic intonations. Finally, different acoustic measures of angry expressions were associated with activity in the left STG, bilateral inferior frontal gyrus, and dorsal BG.

Effect of MAOA Genotype on Resting-State Networks in Healthy Participants

Up to now, it remains unclear how monoamine oxidase A (MAOA), which has been repeatedly linked to aggression, affects brain activity within resting-state networks (RSN). Here, we used functional magnetic resonance imaging (fMRI) to test whether the MAOA genotype might influence activity within the common RSN. Our results demonstrate that during rest, participants with the low-activity genotype (MAOA-L) exhibit more activity within frontoparietal and temporal parts of the default mode network (DMN) and the cerebellum. The executive control and salience RSN revealed reduced activity for the MAOA-L group in several areas related to executive control, namely the right middle frontal gyrus (BA 6 and BA 9), and the dorsal part of the anterior cingulate cortex. Participants with the high-activity genotype (MAOA-H) showed increased activity in the posterior cingulate part of the DMN. Taken together, we found widespread hyperactivity within the DMN and reduced activity in brain areas related to executive and inhibitory control for the MAOA-L group. We discuss how these first results examining the influence of MAOA on the resting brain might be related to previous findings regarding the genetics of aggression, while acknowledging that this is an exploratory study which needs further confirmation.

Violence among people with schizophrenia: phenotypes and neurobiology

People with schizophrenia are at increased risk, as compared to the general population, to acquire convictions for violent crimes and homicide. They also show elevated levels of aggressive behaviour. While psychotic symptoms explain aggressive behaviour that is common during acute episodes, they do not explain such behaviour at other stages of illness or prior to illness onset. Three distinct phenotypes have been identified: individuals with a childhood onset of conduct disorder who display antisocial and aggressive behaviour both before and after schizophrenia onset; individuals with no history of conduct problems who begin engaging in aggressive behaviour as illness onsets; and individuals who after many years of illness engage in a severe physical assault. Little is known about the aetiology of the three types of offenders and about the neural mechanisms that initiate and maintain these behaviours. We hypothesize that schizophrenia preceded by conduct disorder is associated with a combination of genes conferring vulnerability for both disorders and altering the effects of environmental factors on the brain, and thereby, with a distinct pattern of neural development. Some evidence is available to support this hypothesis. By contrast, offending among adults with schizophrenia who have no history of such behaviour prior to illness may result from the changes in the brain that occur as illness onsets, and that are further altered by comorbid conditions such as substance misuse, or by the progressive changes in the brain through adulthood that may result from the illness and from the use of antipsychotic medications.

The spectrum of borderline personality disorder: a neurophysiological view

Borderline Personality Disorder (BPD) has been defined as a personality disorder in all editions of DSM since 1980; namely, DSM III through V. The criteria are a mixture of symptoms and traits; the etiology, a heterogeneous array of genetic, constitutional, and environmental factors. Until recently the diagnosis relied on clinical descriptions. In the last two decades, neurophysiological data, including MRI and fMRI, have established correlates in various brain regions, particularly those involving the frontal lobes and various limbic structures, that show promise of providing a more substantial basis for diagnosis-relying primarily on (internal) brain changes, rather than on (external) clinical observation. Some of the changes in BPD consist of decreased volume in the orbitofrontal and dorsolateral prefrontal cortices and smaller volume in both the amygdala and hippocampus, though with heightened reactivity in the amygdala. Similar abnormalities have been noted in bipolar disorders (BDs) and in ADHD, both of which often accompany BPD and share certain clinical features. Persons with strong genetic predisposition to BDs can develop BPD even in the absence of adverse environmental factors; those with extreme adverse environmental factors (chiefly, early sexual molestation) can develop BPD in the absence of bipolar vulnerability. In some BPD patients, both sets of factors are present. As ideal treatment depends on careful analysis of these factors, neurophysiological testing may permit both more rational, brain-based diagnostic decisions and more appropriate therapeutic strategies.

Neurobiological mechanisms for impulsive-aggression: the role of MAOA

Aggression may be present across a large part of the spectrum of psychopathology, and underlies costly criminal antisocial behaviors. Human aggression is a complex and underspecified construct, confounding scientific discovery. Nevertheless, some biologically tractable subtypes are apparent, and one in particular-impulsive (reactive) aggression-appears to account for many facets of aggression-related dysfunction in psychiatric illness. Impulsive-aggression is significantly heritable, suggesting genetic transmission. However, the specific neurobiological mechanisms that mediate genetic risk for impulsive-aggression remain unclear. Here, we review extant data on the genetics and neurobiology of individual differences in impulsive-aggression, with particular attention to the role of genetic variation in Monoamine Oxidase A (MAOA) and its impact on serotonergic signaling within corticolimbic circuitry.

High frequency TMS for the management of Borderline Personality Disorder: a case report

OBJECTIVE

To assess the effect of repetitive trans-cranial magnetic stimulation (rTMS) therapy in the management of Borderline Personality Disorder (BPD).

METHOD

The subject was a 22 years old girl. She was first diagnosed with BPD after one of her suicidal attempts about two years ago. She received 10 sessions of high-frequency TMS over her left dorsolateral prefrontal cortex. Assessment was done before treatment, exactly after the last session, one and three months after treatment. Functional Scanning was performed before and after the TMS sessions and one month after the last session.

RESULTS

Results of block design analysis revealed increased activity in amygdala, Superior Temporal Gyrus, Superior Frontal Gyrus, Middle Frontal Gyrus and parahippocampus in negative-neutral and negative-rest contrasts. In contrast to the mentioned areas that exhibited decrease in activity after treatment, we found that middle temporal gyrus and post central gyrus were activated by the emotional stimuli. The changes in brain activity were associated with decrease in BPD severity (measured by BPD severity index) and depression and impulsivity level.

CONCLUSION

Regardless of the limitations of this study, our findings suggest a positive role for rTMS in the management of BPD.

Anger induced by interferon-alpha is moderated by ratio of arachidonic acid to omega-3 fatty acids

OBJECTIVE

Anger worsens in some patients during interferon-alpha (IFN-α) therapy. Elevated anger has also been associated with lower long-chain omega-3 (LCn-3) fatty acid levels. We examined whether fatty acids could influence vulnerability to anger during IFN-α exposure.

METHODS

Plasma arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) levels were determined prior to IFN-α therapy by mass spectroscopy. Repeated-measure analyses examined the relationship between AA/EPA+DHA and the subsequent development of labile anger and irritability in 82 subjects who prospectively completed the Anger, Irritability, and Assault Questionnaire (AIAQ) during the first eight weeks of IFN-α therapy.

RESULTS

Prior to IFN-α therapy, AA/EPA+DHA did not correlate with either labile anger or irritability. Pre-treatment AA/EPA+DHA did correlate with the subsequent maximal increase in labile anger during IFN-α therapy (r=0.33; p=0.005). Over time, labile anger increased more in subjects with above median AA/EPA+DHA ratios (p<0.05). Of the 17 subjects ultimately requiring psychiatric intervention for anger, 14/17 had above-median AA/EPA+DHA ratios (p=0.009). There was also an interaction with the tumor necrosis factor-alpha (TNF-α) promoter polymorphism (A-308G), such that only those with both elevated AA/EPA+DHA and the A allele had increased labile anger (p=0.001). In an additional 18 subjects, we conversely observed that selective serotonin reuptake inhibitor treatment was associated with increased irritability during IFN-α therapy.

CONCLUSION

LCn-3 fatty acid status may influence anger development during exposure to elevated inflammatory cytokines, and may interact with genetic risk for increased brain TNF-α. LCn-3 supplements may be one strategy for minimizing this adverse side effect of IFN-α.

Anger under control: neural correlates of frustration as a function of trait aggression

Antisocial behavior and aggression are prominent symptoms in several psychiatric disorders including antisocial personality disorder. An established precursor to aggression is a frustrating event, which can elicit anger or exasperation, thereby prompting aggressive responses. While some studies have investigated the neural correlates of frustration and aggression, examination of their relation to trait aggression in healthy populations are rare. Based on a screening of 550 males, we formed two extreme groups, one including individuals reporting high (n=21) and one reporting low (n=18) trait aggression. Using functional magnetic resonance imaging (fMRI) at 3T, all participants were put through a frustration task comprising unsolvable anagrams of German nouns. Despite similar behavioral performance, males with high trait aggression reported higher ratings of negative affect and anger after the frustration task. Moreover, they showed relatively decreased activation in the frontal brain regions and the dorsal anterior cingulate cortex (dACC) as well as relatively less amygdala activation in response to frustration. Our findings indicate distinct frontal and limbic processing mechanisms following frustration modulated by trait aggression. In response to a frustrating event, HA individuals show some of the personality characteristics and neural processing patterns observed in abnormally aggressive populations. Highlighting the impact of aggressive traits on the behavioral and neural responses to frustration in non-psychiatric extreme groups can facilitate further characterization of neural dysfunctions underlying psychiatric disorders that involve abnormal frustration processing and aggression.

The brain in overdrive: a new look at borderline and related disorders

Borderline personality disorder (BPD) has been recognized as heterogeneous, etiologically, stemming from many combinations of genetic and environmental factors BPD never occurs alone: it is always accompanied by traits of other personality disorders and by various symptom-conditions, especially mood disorders. The controversy about linkage between BPD and bipolar disorder could not be resolved when the debate relied only on clinical description. Some twin-studies suggested modest overlap between BPD and bipolar disorder. Current neuroimaging research points to similarities in brain changes among several conditions characterized by emotional over-reactivity to stress: bipolar disorder, certain cases of BPD and attention-deficit hyperactivity (ADHD). These include alterations in the limbic system (e.g., amygdala and hippocampus) and neocortex (especially the prefrontal cortex). An important subset of BPD exists in which brain changes are essentially identical with those of bipolar disorder. Relevant brain-change findings and treatment implications are summarized in this article.

Developmental trajectories of abuse--an hypothesis for the effects of early childhood maltreatment on dorsolateral prefrontal cortical development

The United States has a high rate of child maltreatment, with nearly 12 in 1000 children being victims of abuse or neglect. Child abuse strongly predicts negative life outcomes, especially in areas of emotional and mental health. Abused children are also more likely than their peers to engage in violence and enter the juvenile justice system, as well as to become abusive parents themselves. Research has shown that child abuse and trauma can lead to decreased hippocampal volume, which could be indicative of abnormal hippocampal development. Hippocampal development appears to directly affect the development of the dorsolateral prefrontal cortex, a brain area responsible for emotion regulation, cognitive reappraisal, and general executive function. Therefore, I hypothesize that if child abuse results in abnormal hippocampal development, which leads to abnormal dorsolateral prefrontal cortex development, many of the correlated risk factors of child abuse, such as emotionally-laden parenting and unfavorable cognitive distortions regarding children's behaviors, may be in part caused by underdevelopment or abnormal functioning of the dorsolateral prefrontal cortex, as a function of the individual's own experiences with abuse during childhood. If this hypothesis is supported with future research, more targeted, successful, and cost-effective prevention and treatment protocols could ensue. For instance, programs that have been empirically shown to increase the activity of the dorsolateral prefrontal cortex, such as cognitive behavioral therapy, could be effective in decreasing the incidence of intergenerational transfer of abuse.

Aversive Pavlovian Control of Instrumental Behavior in Humans

Adaptive behavior involves interactions between systems regulating Pavlovian and instrumental control of actions. Here, we present the first investigation of the neural mechanisms underlying aversive Pavlovian–instrumental transfer using fMRI in humans. Recent evidence indicates that these Pavlovian influences on instrumental actions are action-specific: Instrumental approach is invigorated by appetitive Pavlovian cues but inhibited by aversive Pavlovian cues. Conversely, instrumental withdrawal is inhibited by appetitive Pavlovian cues but invigorated by aversive Pavlovian cues. We show that BOLD responses in the amygdala and the nucleus accumbens were associated with behavioral inhibition by aversive Pavlovian cues, irrespective of action context. Furthermore, BOLD responses in the ventromedial prefrontal cortex differed between approach and withdrawal actions. Aversive Pavlovian conditioned stimuli modulated connectivity between the ventromedial prefrontal cortex and the caudate nucleus. These results show that action-specific aversive control of instrumental behavior involves the modulation of fronto-striatal interactions by Pavlovian conditioned stimuli.

Structural brain alterations associated with schizophrenia preceded by conduct disorder: a common and distinct subtype of schizophrenia?

Conduct disorder (CD) prior to age 15 is a precursor of schizophrenia in a minority of cases and is associated with violent behavior through adulthood, after taking account of substance misuse. The present study used structural magnetic imaging to examine gray matter (GM) volumes among 27 men with schizophrenia preceded by CD (SZ+CD), 23 men with schizophrenia but without CD (SZ-CD), 27 men with CD only (CD), and 25 healthy (H) men. The groups with schizophrenia were similar in terms of age of onset and duration of illness, levels of psychotic symptoms, and medication. The 2 groups with CD were similar as to number of CD symptoms, lifelong aggressive behavior, and number of criminal convictions. Men with SZ+CD, relative to those with SZ-CD, displayed (1) increased GM volumes in the hypothalamus, the left putamen, the right cuneus/precuneus, and the right inferior parietal cortex after controlling for age, alcohol, and drug misuse and (2) decreased GM volumes in the inferior frontal region. Men with SZ+CD (relative to the SZ-CD group) and CD (relative to the H group) displayed increased GM volumes of the hypothalamus and the inferior and superior parietal lobes, which were not associated with substance misuse. Aggressive behavior, both prior to age 15 and lifetime tendency, was positively correlated with the GM volume of the hypothalamus. Thus, among males, SZ+CD represents a distinct subtype of schizophrenia. Although differences in behavior emerge in childhood and remain stable through adulthood, further research is needed to determine whether the differences in GM volumes result from abnormal neural development distinct from that of other males developing schizophrenia.

Opportunities, threats and limitations of neuroscience data in forensic psychiatric evaluation

PURPOSE OF REVIEW

In the last decade, a number of studies have been published to shed light on the interaction between neuroscience and the law, notably on the introduction of neuroscience data in forensic psychiatric evaluation (FPE). Even if there is a growing consensus on the relevance of neuroscience in clinical practice, the role of neuroscience in FPE is still controversial.

RECENT FINDINGS

The use of neuroscience data in FPE can support the detection of psychopathological disabilities (e.g. deficit of self-control, aggressiveness) that may be involved in criminal action. Traumatic brain injury-related clinical disorders that may lead to misconduct have a relevant role in the debate. Traditionally, literature refers also to rare and weird cases in which brain tumours, infections and morphological abnormalities were supposed to be significantly associated with disorders leading to criminal action.

SUMMARY

After reviewing recent literature from both legal and neuroscientific perspectives, we consider a broader range of clinical conditions (e.g. disorders of consciousness in sleepwalking, dopamine replacement therapy in Parkinson's disease, misattributions of self in delusional experience) that may have implications in legal settings. Obviously, it would be possible to consider also different clinical conditions. We conclude by suggesting further experimental and theoretical analysis.

Childhood abuse is associated with structural impairment in the ventrolateral prefrontal cortex and aggressiveness in patients with borderline personality disorder

Volume reduction and functional impairment in areas of the prefrontal cortex (PFC) have been found in borderline personality disorder (BPD), particularly in patients with a history of childhood abuse. These abnormalities may contribute to the expression of emotion dysregulation and aggressiveness. In this study we investigated whether the volume of the PFC is reduced in BPD patients and whether a history of childhood abuse would be associated with greater PFC structural changes. Structural MRI data were obtained from 18 BPD patients and 19 healthy individuals matched for age, sex, handedness, and education and were analyzed using voxel based morphometry. The Child Abuse Scale was used to elicit a past history of abuse; aggression was evaluated using the Buss-Durkee Hostility Inventory (BDHI). The volume of the right ventrolateral PFC (VLPFC) was significantly reduced in BPD subjects with a history of childhood abuse compared to those without this risk factor. Additionally, right VLPFC gray matter volume significantly correlated with the BDHI total score and with BDHI irritability and negativism subscale scores in patients with a history of childhood abuse. Our results suggest that a history of childhood abuse may lead to increased aggression mediated by an impairment of the right VLPFC.

Reduced cortisol in boys with early-onset conduct disorder and callous-unemotional traits

BACKGROUND

A growing body of evidence suggests an association between altered hypothalamic-pituitary-adrenal axis reactivity and the development of persistent antisocial behavior in children. However the effects of altered cortisol levels remain poorly understood in the complex context of conduct disorder, callous-unemotional (CU) personality traits, and frequent comorbidities, such as attention deficit hyperactivity disorder (ADHD). The aim of the current study was to investigate associations among CU traits, antisocial behavior, and comorbid ADHD symptomatology with cortisol levels in male children and adolescents.

METHODS

The study included 37 boys with early-onset conduct disorder (EO-CD, mean age 11.9 years) and 38 healthy boys (mean age 12.5 years). Participants were subjected to multiple daytime salivary cortisol measurements and a psychometric characterization.

RESULTS

Subjects in the EO-CD group with elevated CU traits showed a diminished cortisol awakening response compared to healthy participants. In the EO-CD group, high CU traits and impulsivity were associated with decreased diurnal cortisol levels, while associations with antisocial behavior were not detected. The cortisol awakening response was significantly inversely associated with hyperactivity (P = 0.02) and marginally significant with CU traits (P = 0.07).

CONCLUSIONS

These results indicate a specific association between CU traits and a diminished stress response, which is not explained by antisocial behavior in general.

An open-label study of guanfacine extended release for traumatic stress related symptoms in children and adolescents

OBJECTIVE

The purpose of this open-label pilot study was to investigate the effectiveness and tolerability of guanfacine extended release (GXR) 1-4 mg given in the evening, on the symptoms of traumatic stress (reexperiencing, avoidance, overarousal), generalized anxiety, and functional impairment in children and adolescents with a history of traumatic stress with or without posttraumatic stress disorder (PTSD). As many of our sample had associated attention-deficit/hyperactivity disorder (ADHD) symptoms, we also assessed whether the presence of traumatic stress symptoms impaired the effectiveness of GXR in the treatment of comorbid ADHD symptoms.

METHODS

Participants were 19 children and adolescents 6-18 years of age, with current traumatic stress symptoms. In an 8 week open-label design, each patient's scores on parent-, child-, and clinician-reported symptom rating scales assessing traumatic stress symptoms, generalized anxiety, ADHD symptoms, functional impairment, and global symptom severity and improvement (n=17) were evaluated off and on GXR using χ(2) goodness-of-fit tests, paired t tests, and repeated measures analyses of variance (ANOVAs). To examine patterns of change in outcome measures across treatment, MPlus software was used to conduct linear growth curves modeled with individual-varying times of observation (i.e., random slopes).

RESULTS

Using an average GXR daily dose of 1.19 mg±0.35 mg and an average weight-adjusted daily dose of 0.03 mg/kg±0.01 mg/kg, significant differences were found on all symptom severity measures. Parent reported UCLA Reaction Index scores assessing cluster B (reexperiencing), C (avoidant), and D (overarousal) symptoms significantly improved. In the presence of PTSD symptoms, children with ADHD experienced significantly improved ADHD symptom scores, suggesting that comorbidity does not attenuate an ADHD symptom response to GXR therapy. Medication was generally well tolerated.

CONCLUSIONS

Within the limits of an open-label, hypothesis-generating pilot study, our results suggest that the α2A-adrenoceptor agonist GXR may have therapeutic effects in the treatment of PTSD symptoms in traumatically stressed children and adolescents. The effective dose may be lower than that found for ADHD. Our pilot study supports the need for further controlled research on the effects of GXR and other α2A-adrenoceptor agonists in pediatric disorders of traumatic stress.

What lies beneath the face of aggression?

Recent evidence indicates that a sexually dimorphic feature of humans, the facial width-to-height ratio (FWHR), is positively correlated with reactive aggression, particularly in men. Also, predictions about the aggressive tendencies of others faithfully map onto FWHR in the absence of explicit awareness of this metric. Here, we provide the first evidence that amygdala reactivity to social signals of interpersonal challenge may underlie the link between aggression and the FWHR. Specifically, amygdala reactivity to angry faces was positively correlated with aggression, but only among men with relatively large FWHRs. The patterns of association were specific to angry facial expressions and unique to men. These links may reflect the common influence of pubertal testosterone on craniofacial growth and development of neural circuitry underlying aggression. Amygdala reactivity may also represent a plausible pathway through which FWHR may have evolved to represent an honest indicator of conspecific threat, namely by reflecting the responsiveness of neural circuitry mediating aggressive behavior.

A new look at borderline personality disorder and related disorders: hyper-reactivity in the limbic system and lower centers

Borderline Personality Disorder (BPD) has been often described recently as a condition characterized by emotional dysregulation. Several other conditions share this attribute; namely, Bipolar Disorder (BD), Attention-Deficit/Hyperactivity Disorder (ADHD), Intermittent Explosive Disorder (IED), and Major Depressive Disorder (MDD). The dysregulation is not always in the same direction: BPD, BD, ADHD, and IED, for example, show over-reactivity or "hyperactivity" of emotional responses, whereas patients with MDD show emotional sluggishness and underactivity. At the clinical/descriptive level the "over-reactive" conditions appear separate and distinct. BPD constitutes a large domain within the psychopathological arena, appearing to contain within it a variety of etiologically diverse subtypes. Among the latter is a type of BPD linked closely with Bipolar Disorder; family studies of either condition show an overrepresentation of both: BPD patients with bipolar relatives; Bipolar patients with BPD relatives. A significant percentage of children with ADHD go on to develop either BPD or BD as they approach adulthood. If one shifts the spotlight to neurophysiology, as captured by MRI studies, however, it emerges that an important subtype of BPD, and also BD, ADHD, and IED-share common features of abnormalities and peculiarities in the limbic system and in the cortex, especially the prefrontal cortex. Deeper subcortical regions such as the periaqueductal gray may also be implicated in strong emotional reactions. The diversity of clinical "over-reactive" conditions appear to harken back to a kind of unity at the brain-change level. There are therapeutic implications here, such as the advisability of mood stabilizers in many cases of BPD, not just for Bipolar Disorder.

Peripuberty stress leads to abnormal aggression, altered amygdala and orbitofrontal reactivity and increased prefrontal MAOA gene expression

Although adverse early life experiences have been found to increase lifetime risk to develop violent behaviors, the neurobiological mechanisms underlying these long-term effects remain unclear. We present a novel animal model for pathological aggression induced by peripubertal exposure to stress with face, construct and predictive validity. We show that male rats submitted to fear-induction experiences during the peripubertal period exhibit high and sustained rates of increased aggression at adulthood, even against unthreatening individuals, and increased testosterone/corticosterone ratio. They also exhibit hyperactivity in the amygdala under both basal conditions (evaluated by 2-deoxy-glucose autoradiography) and after a resident-intruder (RI) test (evaluated by c-Fos immunohistochemistry), and hypoactivation of the medial orbitofrontal (MO) cortex after the social challenge. Alterations in the connectivity between the orbitofrontal cortex and the amygdala were linked to the aggressive phenotype. Increased and sustained expression levels of the monoamine oxidase A (MAOA) gene were found in the prefrontal cortex but not in the amygdala of peripubertally stressed animals. They were accompanied by increased activatory acetylation of histone H3, but not H4, at the promoter of the MAOA gene. Treatment with an MAOA inhibitor during adulthood reversed the peripuberty stress-induced antisocial behaviors. Beyond the characterization and validation of the model, we present novel data highlighting changes in the serotonergic system in the prefrontal cortex-and pointing at epigenetic control of the MAOA gene-in the establishment of the link between peripubertal stress and later pathological aggression. Our data emphasize the impact of biological factors triggered by peripubertal adverse experiences on the emergence of violent behaviors.

Paranoid thinking, suspicion, and risk for aggression: a neurodevelopmental perspective

This article represents an effort to extend our understanding of paranoia or suspicion and its development by integrating findings across clinical, developmental, and neuroscience literatures. We first define "paranoia" or paranoid thought and examine its prevalence across typically and atypically developing individuals and theoretical perspectives regarding its development and maintenance. We then briefly summarize current ideas regarding the neural correlates of adaptive, appropriately trusting interpersonal perception, social cognition, and behavior across development. Our focus shifts subsequently to examining in normative and atypical developmental contexts the neural correlates of several component cognitive processes thought to contribute to paranoid thinking: (a) attention bias for threat, (b) jumping to conclusions biases, and (c) hostile intent attribution biases. Where possible, we also present data regarding independent links between these cognitive processes and aggressive behavior. By examining data regarding the behavioral and neural correlates of varied cognitive processes that are likely components of a paranoid thinking style, we hope to advance both theoretical and empirical research in this domain.

Neuroimaging and neurocognitive correlates of aggression and violence in schizophrenia

Individuals diagnosed with major mental disorders such as schizophrenia are more likely to have engaged in violent behavior than mentally healthy members of the same communities. Although aggressive acts can have numerous causes, research about the underlying neurobiology of violence and aggression in schizophrenia can lead to a better understanding of the heterogeneous nature of that behavior and can assist in developing new treatment strategies. The purpose of this paper is to review the recent literature and discuss some of the neurobiological correlates of aggression and violence. The focus will be on schizophrenia, and the results of neuroimaging and neuropsychological studies that have directly investigated brain functioning and/or structure in aggressive and violent samples will be discussed as well as other domains that might predispose to aggression and violence such as deficits in responding to the emotional expressions of others, impulsivity, and psychopathological symptoms. Finally gender differences regarding aggression and violence are discussed. In this context several methodological and conceptional issues that limited the comparison of these studies will be addressed.

Linkage of functional and structural anomalies in the left amygdala of reactive-aggressive men

Amygdala structural and functional abnormalities have been associated to reactive aggression in previous studies. However, the possible linkage of these two types of anomalies has not been examined. We hypothesized that they would coincide in the same localizations, would be correlated in intensity and would be mediated by reactive aggression personality traits. Here violent (n = 25) and non-violent (n = 29) men were recruited on the basis of their reactive aggression. Callous-unemotional (CU) traits were also assessed. Gray matter concentration (gmC) and reactivity to fearful and neutral facial expressions were measured in dorsal and ventral amygdala partitions. The difference between responses to fearful and neutral facial expressions was calculated (F/N-difference). Violent individuals exhibited a smaller F/N-difference and gmC in the left dorsal amygdala, where a significant coincidence was found in a conjunction analysis. Moreover, the left amygdala F/N-difference and gmC were correlated to each other, an effect mediated by reactive aggression but not by CU. The F/N-difference was caused by increased reactivity to neutral faces. This suggests that anatomical anomalies within local circuitry (and not only altered input) may underlie the amygdala hyper-reactivity to social signals which is characteristic of reactive aggression.

Associations between oxytocin receptor gene (OXTR) polymorphisms and self-reported aggressive behavior and anger: Interactions with alcohol consumption

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.

Intrinsic limbic and paralimbic networks are associated with criminal psychopathy

BACKGROUND

Psychopathy is a personality disorder associated with impairments in decision-making, empathy, and impulsivity. Recent brain imaging studies suggest that psychopathy is associated with abnormalities in limbic/paralimbic brain regions. To date, no studies have examined functional brain connectivity measures using independent component analyses (ICA) in adults with psychopathy. Here, we test hypotheses regarding paralimbic connectivity in adult incarcerated individuals stratified by psychopathy scores.

METHODS

One hundred and two prison inmates were rated using the Hare Psychopathy Checklist-Revised (PCL-R). FMRI data were collected while subjects performed an auditory target detection "oddball" task. FMRI data were analyzed using group ICA to identify functional networks responding to the oddball task correlating with psychopathy scores.

RESULTS

Components demonstrating significant correlations with psychopathy included a default mode network, a frontoparietal component, and a visual/posterior cingulate component. Modulation trends correlated strongly with factor 2 (impulsivity) and total PCL-R scores in the frontoparietal and visual/posterior cingulate networks, and with factor 1 (affective) scores within the default mode network. The posterior cingulate region factored significantly in the modulation trends observed.

CONCLUSION

Consistent with the hypothesis of limbic/paralimbic abnormalities associated with psychopathy, modulation trends correlated strongly with PCL-R scores. There is strong evidence to implicate the posterior cingulate in aberrant functional connectivity associated with the manifestation of psychopathic symptoms. Future investigations comparing functional trends associated with the posterior cingulate in psychopathic subjects may provide further insight into the manifestation of this disorder.

Enhanced emotional interference on working memory performance in adults with ADHD

OBJECTIVES

Subjects with attention-deficit/hyperactivity disorder (ADHD) suffer from both executive dysfunction and deficits in emotion regulation. However, up to now, there has been no research demonstrating a clear impact of emotional dysregulation on cognitive performance in subjects with ADHD.

METHODS

Male and female adults with ADHD (n=39) and gender- and IQ-matched control subjects (n=40) performed an emotional working memory task (n-back task). In the background of the task, we presented neutral and negative stimuli varied in emotional saliency (negative pictures with low saliency, negative pictures with high saliency), but subjects were instructed to ignore these pictures and to process the working memory task as quickly and as accurately as possible.

RESULTS

Compared to control subjects, ADHD patients showed both a general working memory deficit and enhanced distractability by emotionally salient stimuli in terms of lower n-back performance accuracy. In particular, while controls showed impaired WM performance when presented with highly arousing negative background pictures, a comparable decrement was observed in the ADHD group already with lowly arousing pictures.

CONCLUSIONS

Our results suggest that difficulties in suppressing attention towards emotionally laden stimuli might result from deficient executive control in ADHD.

Catecholamine influences on dorsolateral prefrontal cortical networks

The symptoms of attention-deficit/hyperactivity disorder (ADHD) involve impairments in prefrontal cortical top-down regulation of attention and behavior. All current pharmacological treatments for ADHD facilitate catecholamine transmission, and basic research suggests that these compounds have prominent actions in the prefrontal cortex (PFC). The dorsolateral PFC is especially sensitive to levels of norepinephrine and dopamine, whereby either too little or too much markedly impairs PFC function. Recent physiological studies have shown that norepinephrine strengthens PFC network connectivity and maintains persistent firing during a working memory task through stimulation of postsynaptic α(2A)-adrenoceptors on PFC neurons. Conversely, dopamine acts at D1 receptors to narrow spatial tuning, sculpting network inputs to decrease noise (i.e., stabilization of the representation). The stimulant medications and atomoxetine appear to enhance PFC function by indirectly increasing these catecholamine actions through blockade of norepinephrine and/or dopamine transporters. In contrast, guanfacine mimics the enhancing effects of norepinephrine at postsynaptic α(2A)-receptors in the PFC, strengthening network connectivity. Stronger PFC regulation of attention, behavior, and emotion likely contributes to the therapeutic effects of these medications for the treatment of ADHD.