Ian Barkataki

Volumetric structural brain abnormalities in men with schizophrenia or antisocial personality disorder

Brain abnormalities are found in association with antisocial personality disorder and schizophrenia, the two mental disorders most implicated in violent behaviour. Structural magnetic resonance imaging was used to investigate the whole brain, cerebellum, temporal lobe, lateral ventricles, caudate nucleus, putamen, thalamus, hippocampus, amygdala and the prefrontal, pre-motor, sensorimotor, occipito-parietal regions in 13 men with antisocial personality disorder, 13 men with schizophrenia and a history of violence, 15 men with schizophrenia without violent history and 15 healthy non-violent men. Compared to controls, the antisocial personality disorder group displayed reductions in whole brain volume and temporal lobe as well as increases in putamen volume. Both schizophrenia groups regardless of violence history exhibited increased lateral ventricle volume, while the schizophrenia group with violent history showed further abnormalities including reduced whole brain and hippocampal volumes and increased putamen size. The findings suggest that individuals with antisocial personality disorder as well as those with schizophrenia and a history of violence have common neural abnormalities, but also show neuro-anatomical differences. The processes by which they came to apparently common ground may, however, differ. The finding of temporal lobe reductions prevalent among those with antisocial personality disorder and hippocampal reduction in the violent men with schizophrenia contributes support for the importance of this region in mediating violent behaviour.

Prefrontal cortex and insight in schizophrenia: a volumetric MRI study.

Previous studies have suggested a relationship between frontal lobe-based neuropsychological functions and insight in schizophrenia. There is some evidence linking both smaller whole brain volume and frontal cortical atrophy to poor insight in this population. We investigated the relationship between total as well as specific prefrontal regional volumes and insight in schizophrenia. Twenty-eight stable outpatients with schizophrenia underwent magnetic resonance imaging scanning and assessment for insight. Insight was measured using the Birchwood self-report Insight Scale and the Expanded Schedule of Assessment of Insight. The whole brain and prefrontal regional (superior frontal, middle frontal, inferior frontal and orbitofrontal) volumes were then manually measured using the Cavalieri method and established criteria. Twenty healthy subjects were also scanned to provide control data for volumetric assessments. Smaller total prefrontal grey matter volume was moderately associated with a lower level of insight into the presence of illness. At the prefrontal sub-regional level, volumes of the superior, inferior and orbitofrontal regions contributed to this relationship, especially in males. It is concluded that smaller prefrontal grey matter volume is associated with poor insight into the presence of illness in stable schizophrenia patients. Future research should examine the association of specific dimensions of insight with frontal as well as non-frontal regional brain volumes.

A neuropsychological investigation into violence and mental illness

Previous research has reported cognitive impairment in patients with schizophrenia and antisocial personality disorder (APD), the two psychiatric illnesses most implicated in violent behaviour. Previous studies have focused on either group exclusively, and have been criticized for procedural inadequacies and sample heterogeneity. The authors investigated and compared neuropsychological profiles of individuals with APD and violent and nonviolent individuals with schizophrenia in a single investigation. The study involved four groups of subjects: (i) individuals with a history of serious violence and a diagnosis of APD, (ii) individuals with a history of violence and schizophrenia, (iii) individuals with schizophrenia without a history of violent behaviour and (iv) healthy control subjects. All study groups were compared on a neuropsychological battery designed to assess general intellectual function, executive function, attention, and processing speed. Cognitive deficits were more widespread among individuals with schizophrenia regardless of history of violence, compared with those with APD. Significant impairment in patients with APD was limited to processing speed. Violent individuals with schizophrenia demonstrated poorer performance than their nonviolent schizophrenia peers on a measure of executive function. Different cognitive impairments are manifested by individuals with APD and schizophrenia with violent behaviours, suggesting differences in underlying pathology. Furthermore, cognitive impairment appears to be more a feature of schizophrenia than of violent behaviour, although there is evidence that a combination of schizophrenia and violent behaviour is associated with greater cognitive deficits.

Dysfunctional, but not functional, impulsivity is associated with a history of seriously violent behaviour and reduced orbitofrontal and hippocampal volumes in schizophrenia

Aggression and violent acts have been linked with impulsive responding. We investigated whether impulsive personality trait, especially suggestive of dysfunctional impulsivity (i.e. fast and inaccurate responding where this is non-optimal), is associated with a history of seriously violent behaviour and specific brain deficits in schizophrenia. Twenty-four male participants with schizophrenia, of whom 10 had a history of serious physical violence, and 14 healthy male participants were assessed on impulsiveness (dysfunctional impulsivity), venturesomeness (functional impulsivity), and empathy. All participants underwent magnetic resonance imaging. The results revealed that participants with schizophrenia and a history of violence showed elevated impulsiveness but had comparable scores on venturesomeness and empathy dimensions. Impulsiveness scores correlated negatively with reduced orbitofrontal grey matter volume in both the patient and healthy control groups, and with hippocampal volume in the patient group. Our findings suggest that dysfunctional, but not functional, impulsivity is elevated in patients with schizophrenia with a propensity for repetitive violence, and this in turn appears to be associated with reduce volumes of both the orbitofrontal cortex grey matter and the hippocampus. Violence risk prediction and management strategies in schizophrenia may benefit from including specific measures of dysfunctional impulsive traits.

Association between violent behaviour and impaired prepulse inhibition of the startle response in antisocial personality disorder and schizophrenia

Violent behaviour has a strong association with antisocial personality disorder (APD) and schizophrenia. Although developments in the understanding of socio-environmental factors associated with violence should not be ignored, advances in prevention and treatment of violent behaviour would benefit by improved understanding of its neurobiological and cognitive basis. The authors, therefore, investigated prepulse inhibition (PPI) of the startle response in APD and schizophrenia in relation to a history of serious violence. The neural substrates of PPI, especially the hippocampus, amygdala, thalamus and basal ganglia, are implicated in violence as well as in APD and schizophrenia. The study included four groups: (i) patients with APD and a history of violence, (ii) patients with schizophrenia and a history of violence, (iii) patients with schizophrenia without a history of violence, and (iv) healthy subjects with no history of violence or a mental disorder. All subjects were assessed identically on acoustic PPI. Compared to healthy subjects, significantly reduced PPI occurred in APD, violent schizophrenia and non-violent schizophrenia patients. Although PPI did not significantly differentiate the three clinical groups, high ratings of violence were modestly associated with reduced PPI across the entire study sample. Violent patients with impulsive and premeditated violence showed comparable PPI. The association between violent behaviour and impaired PPI suggests that neural structures and functions underlying PPI are implicated in (inhibition of) violence.

Neural correlates of deficient response inhibition in mentally disordered violent individuals

In this study, response inhibition and associated neural activation during a motor inhibition paradigm were investigated in (i) men with antisocial personality disorder (APD) with a history of violence (n = 14), (ii) men with schizophrenia with a history of violence (n = 12), (iii) men with schizophrenia without a history of violence (n = 12), and (iv) healthy control subjects (n = 14) using functional magnetic resonance imaging (fMRI). At the behavioural level, individuals with schizophrenia showed impaired performance across all conditions, whereas an increased error rate was seen in the APD group only during the conditions requiring inhibition. At the neural level, both violent groups showed reduced thalamic activity, compared with controls, in association with modulation of inhibition by task demands. In addition, the violent schizophrenia group, compared with controls, showed reduced activity in the caudate nucleus during the condition requiring inhibition. It is concluded that violence may not be specifically associated with impaired voluntary inhibition in schizophrenia but this is likely in APD. Reduced thalamic function, perhaps due to its known association with sensorimotor disturbances, is implicated in violent behaviour across both disorders. In addition, caudate dysfunction may contribute, given its role in timing and temporal processing as well as suppression of motor actions, to deficient inhibition and violent behaviour in schizophrenia.

Lower anterior cingulate volume in seriously violent men with antisocial personality disorder or schizophrenia and a history of childhood abuse

Objective: Antisocial personality disorder (ASPD) and schizophrenia, as well as childhood abuse, are associated with violent behaviour and show marked volumetric reduction in the anterior cingulate (AC), a brain region implicated in regulation of violence through its involvement in decision making, empathy, impulse control, and emotion regulation. The present study examined, for the first time to the authors’ knowledge, the grey matter volume of the AC in relation to seriously violent behaviour and childhood psychosocial deprivation (including physical and sexual abuse) in the context of a mental disorder (schizophrenia or ASPD). Methods: Fifty-seven men [14 with ASPD and a history of serious violence; 13 with schizophrenia and a history of serious violence (VSZ); 15 with schizophrenia without a violence history (SZ); 15 nonviolent healthy participants] underwent whole-brain magnetic resonance imaging and were rated on the presence of physical abuse, sexual abuse, neglect, extreme poverty, foster home placement, criminal parent, severe family conflict, and broken home (collectively ‘psychosocial deprivation’). Stereological volumetric ratings of the AC were examined for group differences and their association with childhood psychosocial deprivation. Results: A higher proportion of ASPD and VSZ patients had suffered psychosocial deprivation as children, in particular severe physical abuse, relative to SZ patients and healthy participants. ASPD and VSZ, but not SZ, patients had significantly lower AC volume relative to healthy participants. AC volumes correlated negatively with (total) psychosocial deprivation as well as physical and sexual abuse ratings. Group differences in AC volume became nonsignificant when psychosocial deprivation ratings were covaried for. Conclusions: Violent mentally disordered individuals with ASPD or schizophrenia suffer from a significant AC volume loss and this deficit, at least in part, is explained by their histories of stressful childhood experiences. Current and future therapies aiming to reduce violence in such populations would benefit by attending to biological (and other) correlates of childhood abuse.

P03-257 - Dysfunctional impulsivity in schizophrenia: a functional MRI investigation

Introduction Dysfunctional impulsivity reflects ‘recklessness without deliberation and evaluation of consequences’ and has negative consequences whereas functional impulsivity reflects ‘rapid responding to situational demands in order to maximise ones circumstances’ and often has positive consequences (1). Objective To examine the functional brain basis of dysfunctional impulsivity in healthy people and in people with schizophrenia. Methods Thirteen healthy controls and 21 schizophrenia patients (10/21 with serious repetitive violence) underwent fMRI during a Go/ NoGo task. Dysfunctional impulsivity was indexed using the Impulsiveness subscale and functional impulsivity using the Venturesomeness subscale of the Impulsiveness-Venturesomeness-Empathy questionnaire (2). Results Violent patients had elevated Impulsiveness scores relative to non-violent patients and controls. Impulsiveness did not correlate significantly with task performance in healthy controls or patients. Impulsiveness, but not Venturesomeness, scores correlated during the NoGO condition with lower activity in the anterior cingulate (AC) in controls, and lower inferior temporal and hippocampal activity in patients. Conclusions These findings accord with previously reported associations between reduced hippocampal volume and dysfunctional impulsivity in schizophrenia (3) and, combined with our earlier observations of reduced AC activation during a working memory task in violent antisocial individuals (4), suggest that the influence of dysfunctional impulsivity in antisocial and criminal behaviour is mediated via deficient (inhibitory) functions of the AC and hippocampus.