Homo ferox: The contribution of functional brain studies to understanding the neural bases of aggressive and criminal behavior

Validation of a new instrument to guide and support insanity evaluations: the defendant's insanity assessment support scale (DIASS)

The insanity defense represents one of the most controversial and debated evaluations performed by forensic psychiatrists and psychologists. Despite the variation among different jurisdictions, in Western countries, the legal standards for insanity often rely on the presence of cognitive and/or volitional impairment of the defendant at the time of the crime. We developed the defendant's insanity assessment support scale (DIASS) based on a wide view of competent decision-making, which reflects core issues relevant to legal insanity in many jurisdictions. To assess the characteristics of the DIASS we asked 40 forensic experts (16% women; years of experience = 20.6 ± 12.9) to evaluate 10 real-life derived forensic cases with the DIASS; cases included defendants' psychiatric symptom severity, evaluated through the 24-itemBrief Psychiatric Rating Scale (BPRS). Exploratory factor analysis by principal axis factoring was conducted, which disclosed a two-factor solution explaining 57.6% of the total variance. The DIASS showed a good internal consistency (Cronbach's alpha = 0.86), and substantial inter-rater reliability (Cohen's kappa = 0.72). The capacities analyzed through the DIASS were mainly affected by mania/excitement and psychotic dimensions in nonresponsible and with substantially diminished responsibility defendants, while by hostility and negative symptoms in responsible defendants. The DIASS proved to be an effective psychometric tool to guide and structure insanity defense evaluations, in order to improve their consistency and reliability.

Translating clinical findings to the legal norm: the Defendant's Insanity Assessment Support Scale (DIASS)

Insanity definition and the threshold for satisfying its legal criteria tend to vary depending on the jurisdictions. Yet, in Western countries, the legal standards for insanity often rely on the presence of cognitive and/or volitional impairment of the defendant at crime time. Despite some efforts having been made to guide and structure criminal responsibility evaluations, a valid instrument that could be useful to guide forensic psychiatrists' criminal responsibility assessments in different jurisdictions is lacking. This is a gap that needs to be addressed, considering the significant forensic and procedural implications of psychiatric evaluations. In addition, differences in methodology used in insanity assessments may also have consequences for the principle of equal rights for all citizens before the law, which should be guaranteed in the European Union. We developed an instrument, the Defendant's Insanity Assessment Support Scale (DIASS), which can be useful to support, structure, and guide the insanity assessment across different jurisdictions, in order to improve reliability and consistency of such evaluations.

Aggressiveness of martial artists correlates with reduced temporal pole grey matter concentration

Perception and practice of violence have hedonistic aspects associated with positive arousal (appetitive aggression). Earlier studies have mainly investigated the aetiology of aggressive behaviour in forensic/psychiatric patients. The present study examined structural brain characteristics in healthy people practicing violent sports (martial artists) compared to controls not showing violent behaviour. Aggressiveness was assessed in 21 male healthy martial artists and 26 age-matched male healthy controls using the aggressivity factors questionnaire (FAF). Participants underwent structural T1-weighted MRI. Grey matter (GM) differences were analysed using voxel-based morphometry. Whole-brain analyses of the main effects of group and aggressiveness and their interaction were computed. An interaction effect between group and aggressiveness was evident in a brain cluster comprising the left temporal pole and left inferior temporal gyrus. In martial artists, aggressiveness was inversely related to mean GM concentration in this cluster while in controls the opposite pattern was evident. Since these temporal brain regions are relevant for emotion/aggression regulation and threat appraisal, the increased GM concentration in aggressive controls might reflect a stronger cognitive top-down inhibition of their aggressiveness. Lower GM concentration in more aggressive martial artists may indicate a reduced need of inhibitory cognitive control because of their improved self-regulation skills.

Altered cerebellar-amygdala connectivity in violent offenders: A resting-state fMRI study

It has repeatedly been reported, that there are differences in grey matter volume (GMV) between violent offenders and non-violent controls. However, it remains unclear, if structural brain abnormalities influence resting-state functional connectivity (RS-fc) between brain regions. Therefore, in the present investigation, 31 male high-risk violent prisoners were compared to 30 non-criminal controls with respect to RS-fc between brain areas. Seed regions for resting-state analysis were selected based on GMV differences between the two groups. Overall, inmates had more GMV in the cerebellum than controls and revealed higher RS-fc between the cerebellum and the amygdala. In contrast, controls relative to prisoners showed higher RS-fc between the cerebellum and the orbitofrontal cortex (OFC). In addition, controls showed more GMV in the dorsolateral prefrontal cortex (DLPFC). Inmates relative to controls had higher RS-fc within the DLPFC. Results are discussed with respect to cerebellar contributions to a brain network underlying moral behavior and violence. Enhanced cerebellar-amygdala connectivity in violent offenders might reflect alterations in the processing of moral emotions. Heightened functional connectivity between cerebellar hemispheres and the OFC in controls could be a correlate of enhanced emotion regulation capacities. Higher functional intra-DLPFC connectivity in violent offenders might represent an effort to regulate emotions.

Molecular genetics and antisocial behavior: where do we stand?

Over the last two decades, it has become increasingly evident that control of aggressive behavior is modulated by the individual genetic profile as well. Several candidate genes have been proposed to play a role in the risk to develop antisocial behavior, and distinct brain imaging studies have shown that specific cortical areas may be functionally and/or structurally impaired in impulsive violent subjects on the basis of their genotypes. In this paper, we review the findings regarding four polymorphisms-MAOA (Monoamine oxidase A) uVNTR, SLC6A4 (solute carrier family 6 (neurotransmitter transporter), member 4) 5HTTLPR, COMT (Catechol-O-methyltransferase) Val158Met and DRD4 (dopamine D4 receptor) VNTR 1-11-that all have been found to be associated with an increased vulnerability for antisocial and impulsive behavior in response to aversive environmental conditions. These results, however, have not been replicated by other studies, likely because of crucial methodological discrepancies, including variability in the criteria used to define antisocial behavior and assessment of environmental factors. Finally, it has been recently proposed that these genetic variants may actually increase the individual susceptibility not merely to the negative environmental factors, but to the positive ones as well. In this view, such alleles would play a wider modulatory role, by acting as "plasticity" rather than "vulnerability" genes. Overall, these findings have potential important implications that span well outside of neuroscience and psychiatry, to embrace ethics, philosophy, and the law itself, as they pose new challenges to the very notion of Free Will. Novel properly controlled studies that examine multi-allelic genetic profiles, rather than focusing on distinct single variants, will make it possible to achieve a clearer understanding of the molecular underpinnings of the nature by nurture interaction.

Neurologic disorder and criminal responsibility

Sufferers from neurologic and psychiatric disorders are not uncommonly defendants in criminal trials. This chapter surveys a variety of different ways in which neurologic disorder bears on criminal responsibility. It discusses the way in which a neurologic disorder might bear on the questions of whether or not the defendant acted voluntarily; whether or not he or she was in the mental state that is required for guilt for the crime; and whether or not he or she is deserving of an insanity defense. The discussion demonstrates that a just determination of whether a sufferer from a neurologic disorder is diminished in his or her criminal responsibility for harmful conduct requires equal appreciation of the nature of the relevant disorder and its impact on behavior, on the one hand, and of the legal import of facts about the psychologic mechanisms through which behavior is generated, on the other.

Personal Liability and Human Free Will in the Background of Emerging Neuroethical Issues

In this paper, the author analyses the issues connected to emerging neurotechnologies, in particular their effects on (legal) concepts like capacity, liability, testimony, and evidence, and also on fundamental constitutional rights and freedoms like the right to autonomy and the right not to be treated without consent (in the general framework of the principle of human dignity). Starting from preliminary remarks on the key-concepts of neuroethics/technoethics, neurolaw/technolaw, the author investigates how personal liability is changing in the framework of new scientific developments. The paper underlines that neurolaw challenges some of the traditional legal institutions in the field of law (e.g., criminal law). From the point of view of ethics, the paper concludes that neuroethics is not challenged by the data coming from the use of emerging neurotechnologies, but human self-perception is strongly affected by it.