Psychopathy--an approach to neuroscientific research in forensic psychiatry

Is the Psychopathic Brain an Artifact of Coding Bias? A Systematic Review

Questionable research practices are a well-recognized problem in psychology. Coding bias, or the tendency of review studies to disproportionately cite positive findings from original research, has received comparatively little attention. Coding bias is more likely to occur when original research, such as neuroimaging, includes large numbers of effects, and is most concerning in applied contexts. We evaluated coding bias in reviews of structural magnetic resonance imaging (sMRI) studies of PCL-R psychopathy. We used PRISMA guidelines to locate all relevant original sMRI studies and reviews. The proportion of null-findings cited in reviews was significantly lower than those reported in original research, indicating coding bias. Coding bias was not affected by publication date or review design. Reviews recommending forensic applications—such as treatment amenability or reduced criminal responsibility—were no more accurate than purely theoretical reviews. Coding bias may have contributed to a perception that structural brain abnormalities in psychopaths are more consistent than they actually are, and by extension that sMRI findings are suitable for forensic application. We discuss possible sources for the pervasive coding bias we observed, and we provide recommendations to counteract this bias in review studies. Until coding bias is addressed, we argue that this literature should not inform conclusions about psychopaths' neurobiology, especially in forensic contexts.

Impulsive and premeditated aggression in male offenders with antisocial personality disorder

INTRODUCTION

Aggression is a clinical symptom of various psychiatric disorders that can be conceptualised as a physical act towards another person with the intent to cause harm. In antisocial personality disorder (ASPD), aggression is a frequent manifestation that differently compromise therapeutic and prognostic goals according to its impulsive or premeditated categorisation. ASPD is characterised by high levels of impulsivity, psychopathic traits, and a high prevalence of co-morbid substance use disorders (SUDs). Aggression in ASPD patients may determine long and recurrent imprisonment thus representing a challenge clinicians and legal experts face.

OBJECTIVES

Our aims were to characterise impulsive and premeditated aggression in male ASPD offenders as well as to determine the potential role of SUDs, impulsivity, and psychopathic traits as predictors.

MATERIALS AND METHODS

In this cross-sectional study we evaluated a sample of ASPD offenders with a battery of clinical and psychometric, standardised instruments: the Psychopathy Checklist-Revised (PCL-R), the European Version of the Addiction Severity Index (EuropASI), the Barratt Impulsivity Scale Version 11 (BIS-11), and the Impulsive/Premeditated Aggression Scale (IPAS).

RESULTS

We used a total sample of 134 offenders, all of whom were male. ASPD patients (n = 96) had a 71.9% prevalence of impulsive aggression and a 28.1% prevalence of premeditated aggression. ASPD patients with impulsive aggression had significantly lower scores of total PCL-R (p<0.01) factor 1 and interpersonal facet 1 (p<0.05), compared with ASPD patients with premeditated aggression. ASPD patients with impulsive aggression and ASPD patients with premeditated aggression had comparable BIS-11 mean scores, and exhibited an equal prevalence of SUDs. The interpersonal facet 1of the PCL-R predicted the aggression type (p<0.05) in ASPD patients, and the exponential beta value for facet 1 was 1.42 (CI = 1.03; 1.95).

CONCLUSIONS

The aggression type that is associated with ASPD is mainly impulsive in nature. ASPD patients who have higher scores of psychopathic traits have a lower probability of exhibiting impulsive aggression and a higher probability of exhibiting premeditated aggression. Although ASPD patients have high levels of impulsivity and a high frequency of SUDs, these two variables were not predictors of the aggression type.

Neurobiological correlates in forensic assessment: a systematic review

BACKGROUND

With the increased knowledge of biological risk factors, interest in including this information in forensic assessments is growing. Currently, forensic assessments are predominantly focused on psychosocial factors. A better understanding of the neurobiology of violent criminal behaviour and biological risk factors could improve forensic assessments.

OBJECTIVE

To provide an overview of the current evidence about biological risk factors that predispose people to antisocial and violent behaviour, and determine its usefulness in forensic assessment.

METHODS

A systematic literature search was conducted using articles from PsycINFO, Embase and Pubmed published between 2000 and 2013.

RESULTS

This review shows that much research on the relationship between genetic predisposition and neurobiological alterations with aggression is performed on psychiatric patients or normal populations. However, the number of studies comparing offenders is limited. There is still a great need to understand how genetic and neurobiological alterations and/or deficits are related to violent behaviour, specifically criminality. Most studies focus on only one of the genetic or neurobiological fields related to antisocial and/or violent behaviour. To reliably correlate the findings of these fields, a standardization of methodology is urgently needed.

CONCLUSION

Findings from the current review suggest that violent aggression, like all forms of human behaviour, both develops under specific genetic and environmental conditions, and requires interplay between these conditions. Violence should be considered as the end product of a chain of life events, during which risks accumulate and potentially reinforce each other, displaying or triggering a specific situation. This systematic review did not find evidence of predispositions or neurobiological alterations that solely explain antisocial or violent behaviour. With better designed studies, more correlation between diverse fields, and more standardisation, it might be possible to elucidate underlying mechanisms. Thus, we advocate maintaining the current case-by-case differentiated approach to evidence-based forensic assessment.

Dimensional assessment of psychopathy and its relationship with physiological responses to empathic images in juvenile offenders

OBJECTIVE

Many psychophysiological studies investigate whether psychopaths present low levels of electrodermal activity (EDA). However, despite evidence that varying degrees of psychopathy are normally distributed in the population, there is a paucity of EDA studies evaluating dimensionally. Moreover, although lack of empathy is a cornerstone of psychopathy, there has been a lack of studies using pictures of empathic emotional content to assess psychophysiological responses.

METHOD

We studied a population of young male delinquents (n = 30) from a detention center, using the Psychopathy Checklist Revised (PCL-R) to determine if higher levels of psychopathy were related to lesser degrees of EDA in response to emotion-eliciting pictures of empathic content.

RESULTS

There were significant correlations (p < 0.05) between latency and peak of EDA responses to unpleasant pictures and factor 1 scores, as well as between lability of EDA responses and factor 2 scores.

CONCLUSION

These results extend previous findings indicating direct relationship between EDA and psychopathy, and suggest that separate investigations of the two PCL-R factors have the potential to unravel more complex relationships between EDA and psychopathy. Also, by demonstrating such associations using emotion-provoking stimuli with empathic content, our results provide a link between levels of psychopathy and biological indices of empathic detachment.

The psychopath magnetized: insights from brain imaging

Psychopaths commit a disproportionate amount of violent crime, and this places a substantial economic and emotional burden on society. Elucidation of the neural correlates of psychopathy may lead to improved management and treatment of the condition. Although some methodological issues remain, the neuroimaging literature is generally converging on a set of brain regions and circuits that are consistently implicated in the condition: the orbitofrontal cortex, amygdala, and the anterior and posterior cingulate and adjacent (para)limbic structures. We discuss these findings in the context of extant theories of psychopathy and highlight the potential legal and policy implications of this body of work.