Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

Wavelet-based motion artifact removal for electrodermal activity

Electrodermal activity (EDA) recording is a powerful, widely used tool for monitoring psychological or physiological arousal. However, analysis of EDA is hampered by its sensitivity to motion artifacts. We propose a method for removing motion artifacts from EDA, measured as skin conductance (SC), using a stationary wavelet transform (SWT). We modeled the wavelet coefficients as a Gaussian mixture distribution corresponding to the underlying skin conductance level (SCL) and skin conductance responses (SCRs). The goodness-of-fit of the model was validated on ambulatory SC data. We evaluated the proposed method in comparison with three previous approaches. Our method achieved a greater reduction of artifacts while retaining motion-artifact-free data.

Comorbidity of schizotypy and psychopathy: skin conductance to affective pictures

Prior research indicates a relationship between psychopathy and schizophrenia, elucidating a specific trajectory toward violence. Recent research has suggested that this relationship exists at the nonclinical trait level of schizotypy; however, this finding has not been examined objectively. To explore this relationship using both subjective and objective measures, 54 undergraduates (50% male; mean age 20.41) who endorsed a wide range of schizotypy on the Schizotypal Personality Questionnaire (SPQ) completed a laboratory-based protocol. Participants viewed 15 pictures (five neutral, five threatening, and five of others in distress) from the International Affective Pictures System while electrodermal activity was recorded. As expected, all participants exhibited increased skin conductance levels (SCL) to threat and distress pictures compared to neutral pictures; however, no difference in SCL was found between threat and distress pictures. A unique relationship between psychopathy and schizotypy was found (i.e., schizotypy was related to higher Self-Centered Impulsivity and lower Fearless Dominance); however, schizotypy was related to increased SCL in response to emotional and neutral pictures. Although results do not support autonomic hyporesponsiveness often found in clinical psychopathy, a positive relationship was found between schizotypy and self-reported physical aggression. Findings highlight the need to examine other trajectories of violence within the schizophrenia spectrum disorders.

Attenuated subjective ratings and skin conductance responses to neutral and negative pictures in non-psychopathic mentally disordered offenders with various diagnoses

Altered autonomic arousal in relation to offending behavior has mainly been investigated in subjects with varying degrees of psychopathic traits. The present study sets out to investigate subjective ratings and skin conductance responses (SCRs) in mentally disordered offenders with various diagnoses but without psychopathy, specifically recruited from the forensic psychiatric system. Two subgroups were investigated; an antisocial group with antisocial personality disorder (APD) or antisocial traits (n=16) and a non-antisocial group with various diagnoses (n=25), in relation to a healthy non-criminal control group (n=20). All participants were male. SCRs and subjective ratings of arousal and valence were measured for neutral and negative pictures from the International Affective Picture System (IAPS). The offenders showed significantly lower SCRs and subjective ratings than the control group. Moreover, there was no significant difference between antisocial and non-antisocial offenders, indicating that antisocial behavior might not be a differential factor. Thus, attenuated emotional responses may be a characteristic shared by mentally disordered offenders overall.

A continuous measure of phasic electrodermal activity

Electrodermal activity is characterized by the superposition of what appear to be single distinct skin conductance responses (SCRs). Classic trough-to-peak analysis of these responses is impeded by their apparent superposition. A deconvolution approach is proposed, which separates SC data into continuous signals of tonic and phasic activity. The resulting phasic activity shows a zero baseline, and overlapping SCRs are represented by predominantly distinct, compact impulses showing an average duration of less than 2 s. A time integration of the continuous measure of phasic activity is proposed as a straightforward indicator of event-related sympathetic activity. The quality and benefit of the proposed measure is demonstrated in an experiment with short interstimulus intervals as well as by means of a simulation study. The advances compared to previous decomposition methods are discussed.

Infusing neuroscience into the study and prevention of drug misuse and co-occurring aggressive behavior

The etiology of behavioral precursors to substance misuse and aggression is viewed from the perspective of a developmental, multifactorial model of complex disorders. Beginning at conception, genetic and environmental interactions have potential to produce a sequence of behavioral phenotypes during development that bias the trajectory toward high-risk outcomes. One pathway is theorized to emanate from a deviation in neurological development that predisposes children to affective and cognitive delays or impairments that, in turn, generate dysregulatory behaviors. The plasticity of these neurobiological systems is highly relevant to the prevention sciences; their functions are reliant upon environmental inputs and can be altered, for better or for worse, contingent upon the nature of the inputs. Thus, social contextual factors confer significant influence on the development of this neural network and behavioral outcomes by increasing risk for, or protecting (1) against, dysregulatory outcomes. A well-designed intervention can exploit the brain's plasticity by targeting biological and social factors at sensitive time points to positively influence emergent neurobiological functions and related behaviors. Accordingly, prevention research is beginning to focus on perturbations in developmental neural plasticity during childhood that increase the likelihood of risky behaviors and may also moderate intervention effects on behavior. Given that the more complex features of neurobiological functions underlying drug misuse and aggression (e.g., executive cognitive function, coping skills, affect regulation) do not coalesce until early adulthood when prefrontal-limbic brain networks consolidate, it is critical that mechanisms underlying developmental risk factors are identified. An empirically driven prevention approach, thus, may benefit from consideration of (i) the type, effect, and developmental timing of the environmental impact on the brain, and (ii) the type and effect on brain function, and developmental timing of the intervention. This translational approach promises to eventually offer some direction for the design of effective interventions to prevent drug misuse and concomitant aggression.

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.

Prädiktoren dissozialen Verhaltens

Many studies have shown that psychophysiological parameters of processing emotional stimuli are associated with different personality traits in children, adolescents, and adults. Individuals with low autonomic baseline arousal, low orienting reaction, accelerated habituation, and reduced excitability particularly to punishing stimuli are characterised by a reduced experience of anxiety, decreased behaviour inhibition, and increased sensation seeking. These characteristics seem to raise the likelihood of dis-social behavior and are perceived as prognostically favourable for the development of antisocial personality disorders in childhood and adolescence. In contrast, an increased disposition towards anxiety, which is associated with increased autonomic reactivity, is recognised as a protective factor. Current data have shown that through special training, child and adolescent autonomic reactivity could be enhanced. Due to its versatility, this biological marker might be used for prevention in children at greater risk of developing antisocial behaviour.

The Reactive-Proactive Aggression Questionnaire: Differential Correlates of Reactive and Proactive Aggression in Adolescent Boys

This study reports the development of the Reactive-Proactive Aggression Questionnaire (RPQ), and the differential correlates of these two forms of aggression. Antisocial, psychosocial and personality measures were obtained at ages 7 and 16 years in schoolboys, while the RPQ was administered to 334 of the boys at age 16 years. Confirmatory factor analysis indicated a significant fit for a two-factor proactive-reactive model that replicated from one independent subsample to another. Proactive aggression was uniquely characterized at age 7 by initiation of fights, strong-arm tactics, delinquency, poor school motivation, poor peer relationships, single-parent status, psychosocial adversity, substance-abusing parents, and hyperactivity, and at age 16 by a psychopathic personality, blunted affect, delinquency, and serious violent offending. Reactive aggression was uniquely characterized at age 16 by impulsivity, hostility, social anxiety, lack of close friends, unusual perceptual experiences, and ideas of reference. Findings confirm and extend the differential correlates of proactive-reactive aggression, and demonstrate that this brief but reliable and valid self-report instrument can be used to assess proactive and reactive aggression in child and adolescent samples.

Cognitive performance and autonomic reactivity in abstinent drug abusers and nonusers

In this study the authors compared the performance of abstinent drug abusers (n = 21) and nonuser control participants (n = 20) in neurocognitive and emotional functions by use of the Rogers Decision Making Task, Gambling Task, Emotional Stroop, impulsivity continuous performance task (CPT), and vigilance CPT. Skin conductance (SC) and heart rate (HR) monitoring was synchronized with task performance. Groups showed similar performance for vigilance, impulsivity, and emotional interference; however, drug abusers showed stronger SC responses. Drug abusers performed more poorly on the Gambling and Rogers Decision Making Tasks. When making risky decisions, drug abusers showed significantly less increase in SC activity than controls and exhibited lower HRs throughout performance on all tasks. In conclusion, complex tasks involving decision making, sensitivity to consequences, and emotional regulation discriminated between drug abusers and controls.

The psychophysiology of child misconduct

Psychophysiological evidence supports the notion that serious and persistent childhood misconduct is symptomatic of an internal dysfunction that dynamically interacts with other psychological and social causes. Childhood misconduct is a complex phenomenon with multiple causes and no easy solutions. Rather than think our civilization is doomed, however, we should realize that the great majority of our children grow up to be sociable and law-abiding individuals. For the others, we are afforded optimism that this problem can be minimized as we gain a more complete understanding of the interplay among biological, psychological, and social risks, and through the consequent refinement of interventions.

Increased psychophysiological arousal and orienting at ages 3 and 11 years in persistently schizotypal adults

Abnormalities of psychophysiological arousal and orienting are thought to predispose to schizophrenia, but there have been no prior studies of early psychophysiological functioning in "persistent schizotypals" who remain stably schizotypal across time. This study assessed skin conductance (SC) arousal and orienting at ages 3 and 11 years, electroencephalography (EEG) at age 11 years, and behavior problems at age 17 years in 52 individuals who were stably schizotypal from ages 17 to 23 years, and 104 normal controls. Schizotypy was assessed at age 17 with the Schizophrenism scale, and at age 23 with the Schizotypal Personality Questionnaire (SPQ). Schizotypals had significantly increased SC arousal and increased SC amplitudes to neutral and aversive stimuli at both ages 3 and 11, and also reduced slow-wave left hemisphere EEG power at the beginning of the Continuous Performance Task (CPT) at age 11. Group differences in SC were greater for aversive than neutral stimuli. Schizotypals also had higher age 17 behavior ratings on psychotic behavior, anxiety-withdrawal, and conduct disorder. Findings indicate that heightened SC arousal and orienting in early childhood is a significant risk factor for later schizotypal personality, support a left hemisphere overactivation hypothesis of schizotypy, and illustrate the potential value of a longitudinal definition of persistent schizotypy.

Autonomic stress reactivity and executive functions in successful and unsuccessful criminal psychopaths from the community

A significant gap in the psychopathy literature is the lack of studies comparing "successful," nonconvicted psychopaths with "unsuccessful," convicted psychopaths. This study tested the hypothesis that successful psychopaths show increased autonomic stress reactivity and better neuropsychological function compared with unsuccessful psychopaths. A total of 26 controls, 16 unsuccessful psychopaths, and 13 successful psychopaths were assessed on psychophysiological measures recorded during an emotional manipulation, the Wisconsin Card Sorting Test (WCST), Wechsler Memory Scale--Revised subtests, and childhood stressors. Compared with controls, unsuccessful psychopaths showed reduced cardiovascular stress reactivity. In contrast, successful psychopaths showed heightened reactivity, better WCST performance, and more parental absence than unsuccessful psychopaths and controls. The implications of these findings and the generalizability of existing psychopathy research are discussed.