Larger striatal volume is associated with increased adult psychopathy.

Prior studies have inconsistently reported increased volumes of the striatum in adults with psychopathy. A meta-analysis presented here indicates an overall effect size of d = 0.44. Nevertheless, variability in findings exist, and questions remain on confounding clinical conditions and generalizability to females. This study tests the hypothesis that striatal volumes are increased in adults with psychopathic traits, and that this relationship is mediated by stimulation-seeking and impulsivity. Striatal volume was assessed using magnetic resonance imaging in 108 adult community-dwelling males alongside psychopathy using the Psychopathy Checklist - Revised. Subsidiary, exploratory analyses were conducted on a small sample of females. Correlational analyses showed that increased striatal volumes were associated with more psychopathic traits (p = .001). Effects were observed for all striatal regions, controlling for age, substance dependence and abuse, antisocial personality disorder, attention deficit hyperactivity disorder, social adversity, and total brain volume. An analysis of 18 psychopathic individuals showed that striatal volumes were increased 9.4% compared with 18 matched controls (p = .01). Psychopathy in females was also significantly associated with increased striatal volume (p = .02). Stimulation-seeking and impulsivity partly mediated the striatal-psychopathy relationship, accounting for 49.4% of this association. Findings from these two samples replicate and build on initial studies indicating striatal enlargement in adults with psychopathy, yielding an updated effect size of d = 0.48. Results are consistent with the notion that striatal abnormalities in individuals with psychopathy partly reflect increased sensation-seeking and impulsivity, and support the hypothesis of abnormal reward processing in psychopathy.

Personality Disorder Traits, Rorschach Performance, and Neuropsychological Functioning in the Case of a Serial Killer: The Importance of a Multilevel Approach in the Assessment of Personalities Associated with Extreme and Repetitive Violence.

The present paper utilized the case study of an incarcerated serial killer ("Keith") to demonstrate how combining three assessment techniques (the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, the Rorschach task, and a comprehensive battery of neuropsychological measures) within a multilevel personality assessment framework might elucidate possible personality-based underpinnings of extreme and repetitive violence-representing a "next wave" of serial killer research while also highlighting the empirical and clinical value of an empirically-neglected multilevel assessment approach. Gacono and Meloy's multimethod "levels" model was selected as a multilevel framework, and Leary's recommended examination of inter-level consistency was utilized as an integrative strategy. Results indicated marked divergencies among Keith's data levels in areas of executive abilities, psychotic symptoms, affective/emotional disconnectivity, and sexual disturbance that suggested areas for potential change (perhaps in therapy), while consistencies among levels in social cognition and object relations suggested more stable characteristics that may be resistant to modification. The application of multilevel personality assessment methods to extremely and repetitively violent persons represents an important clinical approach worthy of future study-potentially having implications for research, clinical and forensic assessment, and treatment, and advancing empirical and clinical understandings of the continuum of interpersonal violence.

Alexithymia and reactive aggression: The role of the amygdala.

Past research suggests an association between reactive aggression and alexithymia, but neural mechanisms underlying this association remain unknown. Furthermore, the relationship between proactive aggression and alexithymia remains untested. This study aimed to: (1) test whether alexithymia is more related to reactive than proactive aggression; and (2) determine whether amygdala, insula, and/or anterior cingulate cortical (ACC) volume could be neurobiological mechanisms for this association. One hundred and fifty-six community males completed the Reactive-Proactive Aggression Questionnaire and the Toronto Alexithymia Scale. Amygdala, insula, and ACC volumes were assessed using MRI. Alexithymia was positively associated with reactive but not proactive aggression. Alexithymia was positively and bilaterally associated with amygdala and anterior cingulate volumes. Reactive aggression was positively associated with right amygdala volume. Controlling for right amygdala volume rendered the alexithymia-reactive aggression relationship non-significant. Results suggest that increased right amygdala volume is a common neurobiological denominator for both alexithymia and reactive aggression. Findings suggest that greater right hemisphere activation may reflect a vulnerability to negative affect, which in turn predisposes to experiencing negative emotions leading to increased aggression. Findings are among the first to explicate the nature of the alexithymia-aggression relationship, with potential clinical implications.

The mediating role of emotional intelligence on the autonomic functioning - Psychopathy relationship.

Reduced autonomic activity is a risk factor for psychopathy, but the mechanisms underlying this association are under-researched. We hypothesize that emotional intelligence mediates this relationship. Emotional intelligence, cognitive intelligence, scores on the Psychopathy Checklist- Revised (PCL-R), skin conductance, and heart rate were assessed in 156 men from communities in Los Angeles. Emotional intelligence fully mediated the relationship between autonomic functioning and total psychopathy after controlling for cognitive intelligence for both autonomic measures. Full mediation was also found when using PCL-R factors and facets as outcome variables, with the exception of a partial mediation of the heart rate - Antisocial facet relationship. These findings are the first to document emotional intelligence as a mediator of the blunted physiological stress activity - psychopathy relationship, and are interpreted within the framework of the somatic marker and somatic aphasia theories of psychopathy. Possible implications for treatment interventions are also discussed.

Psychopathy Moderates the Relationship between Orbitofrontal and Striatal Alterations and Violence: The Investigation of Individuals Accused of Homicide.

Brain structural abnormalities in the orbitofrontal cortex (OFC) and striatum (caudate and putamen) have been observed in violent individuals. However, a uni-modal neuroimaging perspective has been used and prior findings have been mixed. The present study takes the multimodal structural brain imaging approaches to investigate the differential gray matter volumes (GMV) and cortical thickness (CTh) in the OFC and striatum between violent (accused of homicide) and non-violent (not accused of any violent crimes) individuals with different levels of psychopathic traits (interpersonal and unemotional qualities, factor 1 psychopathy and the expressions of antisocial disposition and impulsivity, factor 2 psychopathy). Structural Magnetic Resonance Imaging data, psychopathy and demographic information were assessed in sixty seven non-violent or violent adults. The results showed that the relationship between violence and the GMV in the right lateral OFC varied across different levels of the factor 1 psychopathy. At the subcortical level, the psychopathy level (the factor 1 psychopathy) moderated the positive relationship of violence with both left and right putamen GMV as well as left caudate GMV. Although the CTh findings were not significant, overall findings suggested that psychopathic traits moderated the relationship between violence and the brain structural morphology in the OFC and striatum. In conclusion, psychopathy takes upon a significant role in moderating violent behavior which gives insight to design and implement prevention measures targeting violent acts, thereby possibly mitigating their occurrence within the society.

Associations between psychopathic traits and brain activity during instructed false responding.

Lying is one of the characteristic features of psychopathy, and has been recognized in clinical and diagnostic descriptions of the disorder, yet individuals with psychopathic traits have been found to have reduced neural activity in many of the brain regions that are important for lying. In this study, we examine brain activity in sixteen individuals with varying degrees of psychopathic traits during a task in which they are instructed to falsify information or tell the truth about autobiographical and non-autobiographical facts, some of which was related to criminal behavior. We found that psychopathic traits were primarily associated with increased activity in the anterior cingulate, various regions of the prefrontal cortex, insula, angular gyrus, and the inferior parietal lobe when participants falsified information of any type. Associations tended to be stronger when participants falsified information about criminal behaviors. Although this study was conducted in a small sample of individuals and the task used has limited ecological validity, these findings support a growing body of literature suggesting that in some contexts, individuals with higher levels of psychopathic traits may demonstrate heightened levels of brain activity.

Alpha-amylase reactivity in relation to psychopathic traits in adults.

Recent investigations of the psychobiology of stress in antisocial youth have benefited from a multi-system measurement model. The inclusion of salivary alpha-amylase (sAA), a surrogate marker of autonomic/sympathetic nervous system (ANS) activity, in addition to salivary cortisol, a biomarker of the hypothalamic-pituitary-adrenal (HPA) axis functioning, has helped define a more complete picture of individual differences and potential dysfunction in the stress response system of these individuals. To the authors' knowledge, no studies have examined sAA in relation to antisocial behavior in adults or in relation to psychopathic traits specifically. In the present study, we examined sAA, in addition to salivary cortisol, in a relatively large sample (n=158) of adult males (M age=36.81, range=22-67 years; 44% African-American, 34% Caucasian, 16% Hispanic) recruited from temporary employment agencies with varying levels of psychopathic traits. Males scoring highest in psychopathy were found to have attenuated sAA reactivity to social stress compared to those scoring lower in psychopathy. No differential relationships with the different factors of psychopathy were observed. In contrast to studies of antisocial youth, there were no interactions between sAA and cortisol levels in relation to psychopathy, but there was a significant interaction between pre-stressor levels of sAA and cortisol. Findings reveal potential regulatory deficits in the fast-acting, 'fight or flight', component of the stress response in adult males with psychopathic traits, as well as abnormalities in how this system may interact with the HPA axis.

Frontal information flow and connectivity in psychopathy.

Despite accumulating evidence of structural deficits in individuals with psychopathy, especially in frontal regions, our understanding of systems-level disturbances in cortical networks remains limited. We applied novel graph theory-based methods to assess information flow and connectivity based on cortical thickness measures in 55 individuals with psychopathy and 47 normal controls. Compared with controls, the psychopathy group showed significantly altered interregional connectivity patterns. Furthermore, bilateral superior frontal cortices in the frontal network were identified as information flow control hubs in the psychopathy group in contrast to bilateral inferior frontal and medial orbitofrontal cortices as network hubs of the controls. Frontal information flow and connectivity may have a significant role in the neuropathology of psychopathy.

Somatic aphasia: mismatch of body sensations with autonomic stress reactivity in psychopathy.

BACKGROUND: Although one of the main characteristics of psychopaths is a deficit in emotion, it is unknown whether they show a fundamental impairment in appropriately recognizing their own body sensations during an emotion-inducing task. METHOD: Skin conductance and heart rate were recorded in 138 males during a social stressor together with subjective reports of body sensations. Psychopathic traits were assessed using the Psychopathy Checklist-Revised (PCL-R) 2nd edition (Hare, 2003). RESULTS: Nonpsychopathic controls who reported higher body sensations showed higher heart rate reactivity, but this verbal-autonomic consistency was not found in psychopathic individuals. This mind-body disconnection is particularly associated with the interpersonal-affective factor of psychopathy. CONCLUSIONS: Findings are the first to document this body sensation-autonomic mismatch in psychopaths, and suggest that somatic aphasia - the inaccurate identification and recognition of one's own somatic states - may partly underlie the interpersonal-affective features of psychopathy.

Neurocriminology.

In the past several decades there has been an explosion of research into the biological correlates to antisocial behavior. This chapter reviews the state of current research on the topic, including a review of the genetics, neuroimaging, neuropsychological, and electrophysiological studies in delinquent and antisocial populations. Special attention is paid to the biopsychosocial model and gene-environment interactions in producing antisocial behavior.

Resting EEG deficits in accused murderers with schizophrenia.

Empirical evidence continues to suggest a biologically distinct violent subtype of schizophrenia. The present study examined whether murderers with schizophrenia would demonstrate resting EEG deficits distinguishing them from both non-violent schizophrenia patients and murderers without schizophrenia. Resting EEG data were collected from five diagnostic groups (normal controls, non-murderers with schizophrenia, murderers with schizophrenia, murderers without schizophrenia, and murderers with psychiatric conditions other than schizophrenia) at a brain hospital in Nanjing, China. Murderers with schizophrenia were characterized by increased left-hemispheric fast-wave EEG activity relative to non-violent schizophrenia patients, while non-violent schizophrenia patients instead demonstrated increased diffuse slow-wave activity compared to all other groups. Results are discussed within the framework of a proposed left-hemispheric over-processing hypothesis specific to violent individuals with schizophrenia, involving left hemispheric hyperarousal deficits, which may lead to a homicidally violent schizophrenia outcome.

P3 event-related potentials and childhood maltreatment in successful and unsuccessful psychopaths.

Although P3 event-related potential abnormalities have been found in psychopathic individuals, it is unknown whether successful (uncaught) psychopaths and unsuccessful (caught) psychopaths show similar deficits. In this study, P3 amplitude and latency were assessed from a community sample of 121 male adults using an auditory three-stimulus oddball task. Psychopathy was assessed using the Psychopathy Checklist-Revised (Hare, 2003) while childhood physical maltreatment was assessed using the Conflict Tactic Scale (Straus, 1979). Results revealed that compared to normal controls, unsuccessful psychopaths showed reduced parietal P3 amplitudes to target stimuli and reported experienced more physical abuse in childhood. In contrast, successful psychopaths exhibited larger parietal P3 amplitude and shorter frontal P3 latency to irrelevant nontarget stimuli than unsuccessful psychopaths. This is the first report of electrophysiological processing differences between successful and unsuccessful psychopaths, possibly indicating neurocognitive and psychosocial distinctions between these two subtypes of psychopathy.

Increased testosterone-to-cortisol ratio in psychopathy.

Only a few studies have examined hormones in psychopathy, and results have been mixed. It has been suggested that because hormone systems are highly interconnected, it may be important to examine multiple systems simultaneously to gain a clearer picture of how hormones work together to predispose for a certain construct. In the present study, we attempt to clarify the role of the hormones cortisol and testosterone in psychopathy by examining both hormones in a community sample of 178 adults demonstrating a wide range of psychopathy scores. Results showed that psychopathy scores were associated with an increased ratio of testosterone (baseline) to cortisol responsivity to a stressor. Psychopathy was not associated with either of these measures independently or with baseline cortisol levels. These findings suggest that these highly interconnected hormone systems may work in concert to predispose to psychopathy.

Structural and psychosocial correlates of birth order anomalies in schizophrenia and homicide.

Birth order--a unique index of both neurodevelopmental and/or psychosocial factors in the pathogenesis of psychiatric disorder--remains largely unexplored in violent schizophrenia. We examined whether murderers with schizophrenia would demonstrate birth order anomalies, distinguishing them from both nonviolent schizophrenia patients and murderers without schizophrenia. Self-report birth order, psychosocial history data (i.e., maternal birth age, family size, parental criminality, parental SES), and structural magnetic resonance imaging data were collected from normal controls, nonviolent schizophrenia patients, murderers with schizophrenia, murderers without schizophrenia, and murderers with psychiatric conditions other than schizophrenia at a brain hospital in Nanjing, China. Results indicated that murderers with schizophrenia were characterized by significantly increased (i.e., later) birth order compared with both nonviolent schizophrenia patients and murderers without schizophrenia. Additionally, birth order was negatively correlated with gray matter volume in key frontal subregions for schizophrenic murderers, and was negatively correlated with parental SES. Findings may suggest biological, psychosocial, or interactional trajectories which may lead to a homicidally violent outcome in schizophrenia.

Reduced hippocampal and parahippocampal volumes in murderers with schizophrenia.

Evidence has accumulated to suggest that individuals with schizophrenia are at increased risk for violent offending. Furthermore, converging evidence suggests that abnormalities in the fronto-limbic system, including the prefrontal cortex, the hippocampus, and the parahippocampal gyrus, may contribute towards both neuropsychological disturbances in schizophrenia and violent behavior. Since the behavioral and clinical consequences of disturbed fronto-limbic circuitry appear to differ in schizophrenia and violence, it may be argued that patients with schizophrenia who exhibit violent behavior would demonstrate different structural abnormalities compared to their non-violent counterparts. However, the neurobiological basis underlying homicide offenders with schizophrenia remains unclear and little is known regarding the cross-cultural applicability of the findings. Using a 2 x 2 factorial design on a total Chinese sample of 92 males and females, we found reduced gray matter volume in the hippocampus and parahippocampal gyrus in murderers with schizophrenia, in the parahippocampal gyrus in murderers without schizophrenia, and in the prefrontal cortex in non-violent schizophrenia compared to normal controls. Results provide initial evidence demonstrating cross-cultural generalizability of prior fronto-limbic findings on violent schizophrenia. Future studies examining subtle morphological changes in frontal and limbic structures in association with clinical and behavioral characteristics may help further clarify the neurobiological basis of violent behavior.

Comparative meta-analyses of neuropsychological functioning in antisocial schizophrenic persons.

To test the hypothesis that antisocial persons with schizophrenia are characterized by a distinct profile of neurocognitive deficits, meta-analyses of 43 studies were conducted to compare the neuropsychological performance of antisocial schizophrenic individuals to non-antisocial schizophrenic individuals, and to antisocial individuals without schizophrenia. Performance was evaluated across several different domains of neuropsychological functioning for both types of comparisons. Results indicated antisocial schizophrenic individuals demonstrated widespread deficits across multiple domains (Full Scale IQ, Verbal and Performance IQ, attention, broadly-defined executive function, and memory) in comparison to their antisocial counterparts. However, in comparison to their schizophrenic counterparts, persons with antisocial schizophrenia were characterized instead by reduced general intellectual functioning and memory dysfunction (as opposed to hypothesized Verbal IQ and executive function deficits). Findings may suggest a biologically distinct subgroup of antisocial schizophrenic individuals, whose study and treatment require differing approaches from those traditionally used in non-antisocial presentations of schizophrenia.

The neurobiology of psychopathy: a neurodevelopmental perspective.

We provide an overview of the neurobiological underpinnings of psychopathy. Cognitive and affective-emotional processing deficits are associated with abnormal brain structure and function, particularly the amygdala and orbitofrontal cortex. There is limited evidence of lower cortisol levels being associated with psychopathic personality. Initial developmental research is beginning to suggest that these neurobiological processes may have their origins early in life. Findings suggest that psychopathic personality may, in part, have a neurodevelopmental basis. Future longitudinal studies delineating neurobiological correlates of the analogues of interpersonal-affective and antisocial features of psychopathy in children are needed to further substantiate a neurodevelopmental hypothesis of psychopathy.

Psychophysiological and behavioural characteristics of individuals comorbid for antisocial personality disorder and schizophrenia-spectrum personality disorder.

BACKGROUND: Few studies have examined people with comorbid schizophrenia-spectrum personality disorder and antisocial personality disorder, a subgroup who may differ psychophysiologically and behaviourally from those with either condition alone. AIMS: To test whether individuals with both types of personality disorder are particularly characterised by reduced orienting and arousal and by increased criminal offending. METHOD: In a community adult sample, self-reported crime and skin conductance orienting were collected on four diagnostic groups: schizophrenia-spectrum personality disorder only; antisocial personality disorder only; comorbidity of the two disorders; and a control group. RESULTS: The comorbid group showed significantly higher levels of criminal behaviour than the other three groups. They also showed reduced skin conductance orienting to neutral tones compared with the other groups, and significantly reduced arousal and orienting to significant stimuli compared with the control group. CONCLUSIONS: Reduced orienting may reflect a neurocognitive attentional risk factor for both antisocial and schizotypal personality disorders that indirectly reflects a common neural substrate to these disorders.