The structure of schizotypal personality traits: a cross-national study

BACKGROUND

Schizotypal traits are considered a phenotypic-indicator of schizotypy, a latent personality organization reflecting a putative liability for psychosis. To date, no previous study has examined the comparability of factorial structures across samples originating from different countries and cultures. The main goal was to evaluate the factorial structure and reliability of the Schizotypal Personality Questionnaire (SPQ) scores by amalgamating data from studies conducted in 12 countries and across 21 sites.

METHOD

The overall sample consisted of 27 001 participants (37.5% males, n = 4251 drawn from the general population). The mean age was 22.12 years (s.d. = 6.28, range 16-55 years). The SPQ was used. Confirmatory factor analysis (CFA) and Multilevel CFA (ML-CFA) were used to evaluate the factor structure underlying the SPQ scores.

RESULTS

At the SPQ item level, the nine factor and second-order factor models showed adequate goodness-of-fit. At the SPQ subscale level, three- and four-factor models displayed better goodness-of-fit indices than other CFA models. ML-CFA showed that the intraclass correlation coefficients values were lower than 0.106. The three-factor model showed adequate goodness of fit indices in multilevel analysis. The ordinal α coefficients were high, ranging from 0.73 to 0.94 across individual samples, and from 0.84 to 0.91 for the combined sample.

CONCLUSIONS

The results are consistent with the conceptual notion that schizotypal personality is a multifaceted construct and support the validity and utility of SPQ in cross-cultural research. We discuss theoretical and clinical implications of our results for diagnostic systems, psychosis models and cross-national mental health strategies.

Neural mediator of the schizotypy-antisocial behavior relationship

Prior studies have established that schizotypal personality traits (schizotypy) were associated with antisocial behavior (crime), but it is unclear what neural factors mediate this relationship. This study assessed the mediating effect that sub-regional prefrontal gray, specifically the orbitofrontal gray matter volume, has on the schizotypy-antisocial behavior relationship. Five prefrontal sub-regional (superior, middle, inferior, orbitofrontal and rectal gyral) gray matter volumes were assessed using structural magnetic resonance imaging in 90 adults from the community, together with schizotypy and antisocial behavior. Among all five prefrontal sub-regions, the orbitofrontal cortex (OFC) was the major region-of-interest in the present study. Mediation analyses showed that orbitofrontal gray fully mediated the association between schizotypy and antisocial behavior. After having controlled the sex, age, socio-economic statuses, whole brain volumes and substance abuse/dependence of test subjects, the orbitofrontal gray still significantly mediated the effect of schizotypy on antisocial behavior by 53.5%. These findings are the first that document a neural mediator of the schizotypy-antisocial behavior relationship. Findings also suggest that functions subserved by the OFC, including impulse control and inhibition, emotion processing and decision-making, may contribute to the above comorbidity.

A longitudinal biosocial study of cortisol and peer influence on the development of adolescent antisocial behavior

It is increasingly recognized that in order to understand the complex phenomenon of antisocial behavior, interrelations between biological and social risk factors should be taken into account. In the current study, this biosocial approach was applied to examine the mediating role of deviant peers in longitudinal associations linking the level of hypothalamic-pituitary-adrenal (HPA) axis activity to aggression and rule-breaking. Participants were 425 boys and girls from the general population, who were assessed yearly at ages 15, 16, and 17. As a measure of HPA axis activity, cortisol was assessed at awakening, 30, and 60 min later (the cortisol awakening response, CAR). Participants, as well as their best friend, reported on their own aggressive and rule-breaking behavior, thereby allowing to assess bidirectional influences within friendships. Aggression was only predicted by a decreased cortisol level at awakening, and not by aggressive behavior of their friend. Decreased levels of cortisol at awakening predicted adolescents' rule-breaking, which subsequently predicted increased rule-breaking of their best friend. The latter was only found for adolescents who changed friends, as compared to adolescents with the same friend in every year. Gender differences were not found. These findings suggest that interrelations between biological and social risk factors are different for the development of aggression versus rule-breaking. Furthermore, decreased levels of HPA axis activity may represent a susceptibility to selecting deviant peers.

Psychopathic personality in children: genetic and environmental contributions

BACKGROUND

The current study investigates whether the underlying factor structure of psychopathic personality traits found in adults is similar to that in children and what the extent of the genetic and environmental influences are on these psychopathic traits.

METHOD

Psychopathic personality traits were assessed in a community sample of 1219 twins and triplets (age 9-10 years) through caregiver reports of each child's behavior using the Child Psychopathy Scale (CPS).

RESULTS

Confirmatory factor analyses revealed an optimal two-factor solution (callous/disinhibited and manipulative/deceitful) to the CPS subscales. Bivariate genetic modeling of the two computed factor scores revealed significant genetic as well as unique environmental influences on psychopathic personality traits in both boys and girls, with heritability estimates of 0.64 and 0.46, respectively, in boys and 0.49 and 0.58, respectively, in girls. No shared environmental influences on psychopathic personality traits were found.

CONCLUSIONS

The relationship between the two factors was mediated by both genetic and unique environmental factors common to both traits.

Early maternal and paternal bonding, childhood physical abuse and adult psychopathic personality

BACKGROUND

A significant gap in the literature on risk factors for psychopathy is the relative lack of research on parental bonding.MethodThis study examines the cross-sectional relationship between maternal and paternal bonding, childhood physical abuse and psychopathic personality at age 28 years in a community sample of 333 males and females. It also assesses prospectively whether children separated from their parents in the first 3 years of life are more likely to have a psychopathic-like personality 25 years later.

RESULTS

Hierarchical regression analyses indicated that: (1) poor parental bonding (lack of maternal care and low paternal overprotection) and childhood physical abuse were both associated with a psychopathic personality; (2) parental bonding was significantly associated with psychopathic personality after taking into account sex, social adversity, ethnicity and abuse; (3) those separated from parents in the first 3 years of life were particularly characterized by low parental bonding and a psychopathic personality in adulthood; and (4) the deviant behavior factor of psychopathy was more related to lack of maternal care whereas the emotional detachment factor was related to both lack of maternal care and paternal overprotection.

CONCLUSIONS

Findings draw attention to the importance of different components of early bonding in relation to adult psychopathy, and may have potential implications for early intervention and prevention of psychopathy.

Partial divergence of cytokine mRNA expression in bronchial tissues compared to bronchoalveolar lavage cells in horses with recurrent airway obstruction

The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA levels in endobronchial biopsies and bronchoalveolar lavage (BAL) cells were compared. Seven RAO horses were examined while in respiratory crisis following provocation and again while in remission after 2 months on pasture, during which time six healthy horses on pasture were also examined. Quantitative real-time PCR (RT-PCR) was used to assess mRNA expression for cytokines IL-5, IL-6, IL-8, IL-10, IL-17 and transforming growth factor beta1 (TGF-beta1) in endobronchial biopsies and bronchoalveolar lavage. Expression of IL-8 mRNA was significantly upregulated during crisis in both endobronchial biopsies and BAL cells (p=0.036), while there was a similar trend for upregulation of IL-10 mRNA only in BAL cells that approached significance (p=0.059). Moreover, during crisis the expression of IL-8 mRNA in BAL cells was positively correlated to relative IL-6 mRNA expression (r(s)=0.971, p=0.001) and bronchial epithelial expression of IL-10 and TGF-beta1 mRNA were positively correlated (r(s)=0.943, p=0.005). In comparing the relationship of mRNA expression in BAL to biopsy in individual RAO horses, there was a positive correlation with IL-6 to IL-8 mRNA expression in BAL during respiratory crisis (r(s)=0.971, p=0.001) that also correlated positively with IL-8 expression in biopsies on pasture (r(s)=0.986, p<0.0001 for both). Regarding RAO horses at pasture versus controls neither the cytokine mRNA levels in endobronchial biopsy nor in BAL cells differed significantly. These results further support previous findings that IL-8 mRNA in both BAL cells and bronchial epithelium is upregulated in RAO horses during crisis. However, apart from IL-8, it appears that expression of other cytokines, including IL-5, IL-6, IL-10, IL-17 and TGF-beta1 in bronchial epithelium does not necessarily mirror cytokine expression in BAL cells in individual horses with RAO. Accordingly, examination of markers of inflammation in endobronchial tissue provides complementary but not necessarily identical information to that obtained in BAL cells. Given the potential for repeated sampling over time bronchial biopsy can serve as an invaluable additional tool for investigation of time-dependent changes in inflammatory process in this animal model of asthma.

Temporal lobe deficits in murderers: EEG findings undetected by PET

This study evaluates electroencephalography (EEG) and positron emission tomography (PET) in the same subjects. Fourteen murderers were assessed by using both PET (while they were performing the continuous performance task) and EEG during a resting state. EEG revealed significant increases in slow-wave activity in the temporal, but not frontal, lobe in murderers, in contrast to prior PET findings that showed reduced prefrontal, but not temporal, glucose metabolism. Results suggest that resting EEG shows empirical utility distinct from PET activation findings.

Increased height and bulk in antisocial personality disorder and its subtypes

Research suggests that those with antisocial tendencies are larger than controls, but studies have not assessed this association in antisocial personality disorder (APD) or its hypothesized sub-types (i.e. adolescence-limited, late-onset). Height, weight, body mass index, bulk, and psychosocial adversity were assessed in 44 controls, nine adolescent-limited antisocials, 21 APDs, and 13 late-onset antisocials from the community. Adult antisocial individuals, regardless of age of onset, were significantly taller and had greater body bulk than controls. Although groups tended to differ on weight, they did not differ on body mass index. In addition, APDs and adolescent-limited individuals reported greater psychosocial adversity than the other groups. Adversity did not account for height or bulk differences. Results suggest prior findings on height and bulk may apply to APD and support differentiating adolescent-limited and life-course persistent subgroups.

Invariance of the MAST across religious groups

OBJECTIVE

The Michigan Alcoholism Screening Test (MAST), a commonly used instrument of alcohol-related problems, was examined to determine whether it assessed the same constructs in individuals from religions with different proscriptions regarding the use of alcohol.

METHOD

The MAST was completed by participants in the longitudinal Joint Child Health Project when they were approximately 23 years old. Subjects of this study (N= 747; 505 men) were 465 Hindus, 223 Catholics and 59 Muslims who reported drinking alcohol. Measurement invariance, the determination that the same constructs are being measured across groups, was tested by comparing factor invariance using multigroup structural equation modeling.

RESULTS

The Hindu and Catholic groups had similar factor structures to those found in previous Australian, Canadian and U.S. samples. Metric invariance was obtained for the Hindu and Catholic groups, but not for the Muslim group.

CONCLUSIONS

These findings suggest the measurement of MAST factors is invariant across a fairly broad segment of the population in which the MAST might be used. However, the lack of invariance in this sample of Muslims suggests that the MAST is not an appropriate instrument to use among all groups of drinkers. These findings highlight the importance of testing for invariance when using psychological measures to compare heterogeneous samples.

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.

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.

Early educational and health enrichment at age 3-5 years is associated with increased autonomic and central nervous system arousal and orienting at age 11 years: evidence from the Mauritius Child Health Project

Little is known about the effects of environmental enrichment on psychophysiological measures of arousal and orienting in humans. This study tests the hypothesis that early educational and health enrichment is associated with long-term increases in psychophysiological orienting and arousal. One hundred children were experimentally assigned to a two-year enriched nursery school intervention at ages 3-5 years and matched at age 3 years on psychophysiological measures, gender, and ethnicity to 100 comparisons who received the normal educational experience. Children were retested 6-8 years later at age 11 years on skin conductance (SC) and electroencephalogram (EEG) measures of arousal and attention during pre- and postexperimental rest periods and during the continuous performance task. Nursery enrichment was associated with increased SC amplitudes, faster SC rise times, faster SC recovery times, and less slow-wave EEG during both rest and CPT conditions. This is believed to be the first study to show that early environmental enrichment is associated with long-term increases in psychophysiological orienting and arousal in humans. Results draw attention to the important influence of the early environment in shaping later psychophysiological functioning.

Three-factor model of schizotypal personality: invariance across culture, gender, religious affiliation, family adversity, and psychopathology

Whilst the syndrome approach to schizotypy has recently demonstrated differential correlates of a three-factor model of schizotypal personality, variations in the nature of these factors question a basic assumption of this approach. This study tested competing models of the factor structure of schizotypal personality using the Schizotypal Personality Questionnaire (SPQ) in a sample of 1,201 Mauritians. Factor invariance across gender, ethnicity, family adversity, and religion and across a psychopathologically select group was also assessed. Results suggest that a three-factor model, Cognitive-Perceptual Deficits, Interpersonal Deficits, and Disorganization, underlies individual differences across widely varying groups. Other competing three-factor schizotypal personality models did not fit the data better. It is argued that the three-factor Disorganized model is a well-replicated model of DSM schizotypal personality in community samples but possibly not in some clinical samples.

Elevated levels of cognitive-perceptual deficits in individuals with a family history of schizophrenia spectrum disorders

This study finds that the relatives of schizophrenics have elevated scores on the cognitive-perceptual factor of the schizotypal personality questionnaire (SPQ), particularly for the 'unusual perceptual experiences' and 'ideas of reference' subscales. These results support recent findings by Kremen et al. (1998) and suggest that previous failures to demonstrate elevated scores on 'positive' symptoms of schizotypy may be a function of instrumentation.

Structural characterization of a mutant peptide derived from ubiquitin: implications for protein folding

The formation of the N-terminal beta-hairpin of ubiquitin is thought to be an early event in the folding of this small protein. Previously, we have shown that a peptide corresponding to residues 1-17 of ubiquitin folds autonomously and is likely to have a native-like hairpin register. To investigate the causes of the stability of this fold, we have made mutations in the amino acids at the apex of the turn. We find that in a peptide where Thr9 is replaced by Asp, U(1-17)T9D, the native conformation is stabilized with respect to the wild-type sequence, so much so that we are able to characterize the structure of the mutant peptide fully by NMR spectroscopy. The data indicate that U(1-17)T9D peptide does indeed form a hairpin with a native-like register and a type I turn with a G1 beta-bulge, as in the full-length protein. The reason for the greater stability of the U(1-17)T9D mutant remains uncertain, but there are nuclear Overhauser effects between the side chains of Asp9 and Lys 11, which may indicate that a charge-charge interaction between these residues is responsible.

Treatment and prevention implications of antisocial personality disorder

Recent research efforts have focused on understanding the developmental nature of antisocial personality disorder (APD) in order to better develop intervention strategies. This article reviews what is known about biologic and environmental risk factors for the development of APD as well as issues surrounding treatment. Insights into how these factors may work together, and issues involving approaches to researching them, are discussed. Given the impact of this disorder on the lives of the affected individuals as well as society, prevention of this disorder may be a more important focus than intervention.

Reduced prefrontal gray matter volume and reduced autonomic activity in antisocial personality disorder

BACKGROUND

Major damage to gray and white matter in the prefrontal cortex and autonomic deficits have been found to result in pseudopsychopathic personality in patients with neurological disorders, but it is not known whether people with antisocial personality disorder (APD) in the community who do not have discernable brain trauma also have subtle prefrontal deficits.

METHODS

Prefrontal gray and white matter volumes were assessed using structural magnetic resonance imaging in 21 community volunteers with APD (APD group) and in 2 control groups, comprising 34 healthy subjects (control group), 26 subjects with substance dependence (substance-dependent group), and 21 psychiatric controls. Autonomic activity (skin conductance and heart rate) was also assessed during a social stressor in which participants gave a videotaped speech on their faults.

RESULTS

The APD group showed an 11.0% reduction in prefrontal gray matter volume in the absence of ostensible brain lesions and reduced autonomic activity during the stressor. These deficits predicted group membership independent of psychosocial risk factors.

CONCLUSIONS

To our knowledge, these findings provide the first evidence for a structural brain deficit in APD. This prefrontal structural deficit may underlie the low arousal, poor fear conditioning, lack of conscience, and decision-making deficits that have been found to characterize antisocial, psychopathic behavior.

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.

Fearlessness, stimulation-seeking, and large body size at age 3 years as early predispositions to childhood aggression at age 11 years

BACKGROUND

Previous cross-sectional research in Western societies has linked adolescent stimulation-seeking, fearlessness, and body size to antisocial behavior. However, it is unclear how early in life these factors exert their influence, and nothing is known about their specificity to aggressive behavior per se. This study tests the hypotheses that stimulation-seeking, fearlessness, and increased body size at age 3 years predict aggression at age 11 years.

METHODS

Behavioral measures of stimulation-seeking and fearlessness, together with height and weight, were measured at age 3 years and related to ratings of aggression at age 11 years in 1130 male and female Indian and Creole children from the island of Mauritius.

RESULTS

Aggressive children at age 11 years were characterized by increased measures of stimulation-seeking, fearlessness, height, and weight at age 3 years. Stimulation-seeking and height were independently related to aggression, whereas the fearlessness-aggression relationship was mediated by height. Large body size at age 3 years but not 11 years was related to increased aggression at age 11 years, indicating a critical period in development for the influence of body size on aggression.

CONCLUSIONS

Results (1) implicate large body size, stimulation-seeking, and fearlessness in the development of childhood aggression; (2) suggest that there may be a critical period in development in which biological processes influence later aggression; and (3) highlight the importance of early processes in the etiology of aggression.

Reduced prefrontal and increased subcortical brain functioning assessed using positron emission tomography in predatory and affective murderers

There appear to be no brain imaging studies investigating which brain mechanisms subserve affective, impulsive violence versus planned, predatory violence. It was hypothesized that affectively violent offenders would have lower prefrontal activity, higher subcortical activity, and reduced prefrontal/subcortical ratios relative to controls, while predatory violent offenders would show relatively normal brain functioning. Glucose metabolism was assessed using positron emission tomography in 41 comparisons, 15 predatory murderers, and nine affective murderers in left and right hemisphere prefrontal (medial and lateral) and subcortical (amygdala, midbrain, hippocampus, and thalamus) regions. Affective murderers relative to comparisons had lower left and right prefrontal functioning, higher right hemisphere subcortical functioning, and lower right hemisphere prefrontal/subcortical ratios. In contrast, predatory murderers had prefrontal functioning that was more equivalent to comparisons, while also having excessively high right subcortical activity. Results support the hypothesis that emotional, unplanned impulsive murderers are less able to regulate and control aggressive impulses generated from subcortical structures due to deficient prefrontal regulation. It is hypothesized that excessive subcortical activity predisposes to aggressive behaviour, but that while predatory murderers have sufficiently good prefrontal functioning to regulate these aggressive impulses, the affective murderers lack such prefrontal control over emotion regulation.

Prefrontal glucose deficits in murderers lacking psychosocial deprivation

Previous research has suggested that links between autonomic nervous system functioning and violence are strongest in those who come from benign home backgrounds, but there appears to be no similar research using brain-imaging measures of central nervous system functioning. It was hypothesized that murderers who had no early psychosocial deprivation (e.g., no childhood abuse, family neglect) would demonstrate lower prefrontal glucose metabolism than murderers with early psychosocial deprivation and a group of normal controls. Murderers from a previous study, which showed prefrontal deficits in murderers, were assessed for psychosocial deprivation and divided into those with and without deprivation. Murderers without any clear psychosocial deficits were significantly lower on prefrontal glucose metabolism than murderers with psychosocial deficits and controls. These results suggest that murderers lacking psychosocial deficits are characterized by prefrontal deficits. It is argued that among violent offenders without deprived home backgrounds, the "social push" to violence is minimized, and consequently, brain abnormalities provide a relatively stronger predisposition to violence in this group.

Biosocial bases of antisocial behavior: psychophysiological, neurological, and cognitive factors

In this paper we review biosocial research and theory in the area of antisocial behavior. In particular, we focus on interactions between biological and social variables in predicting antisocial outcome. While many psychological researchers make statements concerning the potential importance of biosocial interactions, very few researchers actually test for such interactions in their data. The few studies that have reported biosocial interactions suggest that biological variables can protect against antisocial behavior in socially vulnerable individuals, and that social variables can protect against antisocial behavior in biologically vulnerable individuals. Further research is necessary to determine whether the effects of biosocial interactions on antisocial outcome are dependent upon particular biological or social factors. Preliminary evidence suggests that policy interventions that ameliorate the effects of perinatal risk factors could protect against antisocial and violent outcome.

Low resting heart rate at age 3 years predisposes to aggression at age 11 years: evidence from the Mauritius Child Health Project

OBJECTIVE

Previous studies indicate that low resting heart rate is probably the best-replicated biological correlate of childhood antisocial and aggressive behavior. Nevertheless, there have been few longitudinal tests of this relationship, little control over potential confounds and mediators, and no test of its cross-cultural generalizability. This study tests the hypothesis that low resting heart rate at age 3 years predicts aggression at age 11 years.

METHOD

Resting heart rate at age 3 years was assessed in 1,795 male and female children from Mauritius. Aggressive and nonaggressive forms of antisocial behavior were assessed at age 11 years using the Child Behavior Checklist.

RESULTS

Aggressive children had lower heart rates than nonaggressive children (p < .001). Conversely, those with low heart rates were more aggressive than those with high heart rates (p < .003). There were no interactions with gender or ethnicity. Evidence was found for specificity of low heart rate to aggressive forms of antisocial behavior. Group differences in heart rate were not attributable to 11 biological, psychological, and psychiatric mediators and confounds.

CONCLUSIONS

It is concluded that low resting heart rate, a partly heritable trait reflecting fearlessness and stimulation-seeking, is an important, diagnostically specific, well-replicated, early biological marker for later aggressive behavior.

Brain abnormalities in murderers indicated by positron emission tomography

Murderers pleading not guilty by reason of insanity (NGRI) are thought to have brain dysfunction, but there have been no previous studies reporting direct measures of both cortical and subcortical brain functioning in this specific group. Positron emission tomography brain imaging using a continuous performance challenge task was conducted on 41 murderers pleading not guilty by reason of insanity and 41 age- and sex-matched controls. Murderers were characterized by reduced glucose metabolism in the prefrontal cortex, superior parietal gyrus, left angular gyrus, and the corpus callosum, while abnormal asymmetries of activity (left hemisphere lower than right) were also found in the amygdala, thalamus, and medial temporal lobe. These preliminary findings provide initial indications of a network of abnormal cortical and subcortical brain processes that may predispose to violence in murderers pleading NGRI.

Interaction between birth complications and early maternal rejection in predisposing individuals to adult violence: specificity to serious, early-onset violence

OBJECTIVE

The authors previously reported that birth complications interact with early maternal rejection in predisposing individuals to violence at age 18 years. This study extended the follow-up period for violent offending from 18 years to 34 years, thus increasing the sample of violent offenders threefold and allowing more detailed analyses on onset and type of violence, the form of maternal rejection, and the effect of maternal mental illness.

METHOD

Complications in the births of 4,269 males in Denmark, maternal rejection of these individuals before the age of 1 year, and their histories of criminal offenses at age 34 years were assessed.

RESULTS

The biosocial interaction previously observed held for violent but not nonviolent crime, was specific to more serious forms of violence and not threats of violence, held for early-onset but not late-onset violence, and was not accounted for by psychiatric illness in the mothers. Being reared in a public care institution in the first year of life and the mother's attempt to abort the fetus were the key aspects of maternal rejection that interacted with birth complications in predisposing a subject to violence.

CONCLUSIONS

These findings 1) indicate that the mechanisms underlying early-onset, serious violence differ from those for less serious, late-onset violence, 2) implicate very early factors in the development of violence, 3) highlight the potential importance of integrating psychosocial with biological factors in understanding and preventing violence, and 4) suggest that interventions to reduce birth complications and maternal rejection may help reduce violence.

Heart rate and skin conductance in behaviorally inhibited Mauritian children

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Psychophysiology of anger and violent behavior

Antisocial behavior is a complex phenomenon that arises out of multiple causes involving biologic, psychological, and social forces. Moreover, different forms of violent antisocial behavior may each result from different biopsychosocial pathways. The overview of human psychophysiologic findings presented in this article provides some support for this notion. In particular, the finding of psychophysiologic underarousal (e.g., reduced resting HR and SC levels, increased slow-wave EEG, poor classical conditioning) is one of the most robust and best replicated findings in antisocial populations. The majority of these studies consist of populations exhibiting nonviolent antisocial behavior or milder forms of aggression. Findings of underarousal in institutionalized criminal samples are very few in number and are not well-replicated. The relationship of psychophysiologic underarousal to antisocial behavior, therefore, may be specific to covert forms of antisocial behavior and perhaps to some less severe forms of violent behavior. On the other hand, violence associated with anger and emotional aggression (which is often more impulsive, less controlled, and reactive to some perceived provocation) may have very different psychophysiologic underpinnings. It was suggested that risk factors for emotional aggression include a predisposition to negative affect/arousal and an inability to regulate that affect/arousal. It also was suggested that this effect will be most pronounced in individuals experiencing stressors or adverse social environments, where negative affect and arousal would be increased. Laboratory studies have suggested that overarousal may facilitate aggression in situations in which someone has been provoked. Clinical studies also have indicated a relationship between increased physiologic arousal, negative emotionality, and aggression/antisocial behavior in some populations, with increases in aggression in those also exposed to adverse home environments. Thus, the relationship of increased psychophysiologic arousal to antisocial behavior may be more specific to angry or emotional violence. It is important to note that these psychophysiologic distinctions are speculative for few studies actually have differentiated type of violence in their design. Pitts did group children according to proactive or reactive aggression and found reduced HR levels in both groups, but a substantial increase in HR only in the reactive aggressive group. Lakosina and Trunova found increased SC responsivity in psychopathic individuals characterized by affective violence. These studies provide some initial support for underarousal in proactive/instrumental aggression and overarousal in emotional aggression. It is important, however, that more studies be done with subtypes of violence to test the notion of such differential psychophysiologic patterns. Lastly, some definitional and methodologic considerations need to be mentioned. First, a distinction exists between physiologic arousal and reactivity. Typically, arousal refers to psychophysiologic activity that occurs during a resting state, whereas reactivity refers to activity that occurs in response to some stimulus. Although some studies did assess measures during a resting state, the majority of findings on over-arousal in relation to emotional aggression more accurately reflect psychophysiologic and emotional reactivity to a situation or stimulus. Second, arousal or reactivity are nonspecific terms that can refer to any psychophysiologic response system (e.g., electrodermal, cardiovascular, cortical, and so on). Responses from these systems typically do not correlate in the general population. Thus, it would be worthwhile for future studies to include more than one response system (as done by Raine et al) and see if the arousal/reactivity measures converge. If the measures converge, a general model of arousal or reactivity is supported. (ABSTRACT TRUNCATED)

Psychophysiological protective factors for male subjects at high risk for criminal behavior

OBJECTIVE

This study examines the role of elevated autonomic nervous system reactivity in protecting individuals at high risk for criminal behavior from antisocial outcomes. The authors hypothesized that subjects with criminal fathers who did not become criminals themselves were biologically protected from such an outcome because of, in part, heightened responsiveness of the autonomic nervous system.

METHOD

Ninety-four male subjects were placed into one of four study groups: criminal with criminal father (N = 26), noncriminal with criminal father (N = 24), criminal with noncriminal father (N = 20), and noncriminal with noncriminal father (N = 24). Skin conductance and heart rate data were gathered in an orienting paradigm.

RESULTS

Skin conductance and heart rate orienting reactivity were found to be significantly higher in the group of noncriminal subjects with criminal fathers than in the other three groups.

CONCLUSIONS

For subjects at high risk for criminal behavior, heightened autonomic nervous system responsiveness appears to be associated with lower likelihood of criminal outcome.

Heart rate and skin conductance in behaviorally inhibited Mauritian children

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Childhood behavior precursors of schizotypal personality disorder

No study has yet reported specifically on the early behavior of individuals later diagnosed with schizotypal personality disorder (SPD). This study examines prospectively collected teacher reports on school behavior as a means of assessing childhood precursors of SPD. Thirty-six DSM-III-R diagnosed schizotypal subjects were compared with four other groups: 31 schizophrenia patients, 37 diagnosed as nonpsychotic mentally ill, 68 who were not mentally ill but had mothers with schizophrenia, and 60 who were not mentally ill and had normal parents. These individuals were compared on a teachers' school report questionnaire obtained when the subjects averaged 15.1 years old. Those who later developed SPD were found to be more passive and unengaged and more hypersensitive to criticisms compared with the nonschizophrenia groups. Similar results were found when males and females were examined separately, except that males who developed SPD were found to be less disruptive and hyperexcitable compared with males with schizophrenia; females with SPD did not differ from females with schizophrenia. A receiver operating characteristic analysis found these factors to predict 73.5 percent of future SPDs; the ability of these factors to predict future SPDs is comparable for males and females. These findings suggest that preschizotypal traits may be identified in late childhood or adolescence.

Neuropsychological and psychophysiological correlates of psychosocial functioning in schizophrenia

This study tested hypothesized relationships between neuropsychological and psychophysiological variables and concurrent levels of clinical and psychosocial functioning in schizophrenia. The sample consisted of 40 subjects diagnosed with a chronic schizophrenia spectrum disorder and living in community-based settings. The psychophysiological variables were tonic skin conductance (SC) level, SC reactivity to stressors, and SC response to orienting stimuli. The neuropsychological measures were the Stroop, the Controlled Word Association Test, and four subtests of the Wechsler Adult Intelligence Scale-Revised (block design, digit symbol, digit span, and arithmetic). The psychosocial variables were measures of symptomatology, independent living, work, and social functioning. The results suggested that higher symptoms were associated with higher resting arousal, lower stress reactivity, status as an electrodermal responder, and deficits in verbal fluency and visuo-motor functioning. The pattern for better social functioning was higher resting arousal, lower stress reactivity, and more responses to orienting stimuli. Higher levels of independent living were associated with better visuo-motor and verbal processing. Increased work functioning was associated with better complex visuo-spatial processing. These findings are discussed in terms of (1) the specificity of associations between psychosocial, psychophysiological, and neuropsychological variables and (2) a holistic perspective toward understanding these relationships and their relevance to rehabilitation in schizophrenia.

Abnormal orienting in schizotypal personality disorder

Previous studies have found evidence for skin conductance (SC) orienting abnormalities in psychosis-prone subjects, but there have been no previous studies on subjects with a diagnosis of schizotypal personality disorder. This study assesses whether clinical schizotypal subjects show abnormal habituation to orienting stimuli. Thirteen subjects with both high scores on the Schizotypal Personality Questionnaire (SPQ) and a DSM-III-R clinical diagnosis of schizotypal personality disorder were compared to 30 controls with no such diagnosis and with low scores on the SPQ. While normals showed the expected habituation in SC orienting across trials, schizotypal subjects failed to show a decrement in responding across the first three trials. In a second study on 30 new subjects, individual differences in schizotypy correlated significantly (p = 0.47) and in the predicted direction with a dimensional measure of the orienting deficit. It is hypothesized that this retarded habituation in schizotypals reflects a deficit in preattentive template matching, which may in turn partly relate to the working memory and prefrontal deficits observed in schizotypal and schizophrenia patients.

An approach to global fold determination using limited NMR data from larger proteins selectively protonated at specific residue types

A combination of calculation and experiment is used to demonstrate that the global fold of larger proteins can be rapidly determined using limited NMR data. The approach involves a combination of heteronuclear triple resonance NMR experiments with protonation of selected residue types in an otherwise completely deuterated protein. This method of labelling produces proteins with alpha-specific deuteration in the protonated residues, and the results suggest that this will improve the sensitivity of experiments involving correlation of side-chain ((1)H and (13)C) and backbone ((1)H and (15)N) amide resonances. It will allow the rapid assignment of backbone resonances with high sensitivity and the determination of a reasonable structural model of a protein based on limited NOE restraints, an application that is of increasing importance as data from the large number of genome sequencing projects accumulates. The method that we propose should also be of utility in extending the use of NMR spectroscopy to determine the structures of larger proteins.

Autonomic nervous system factors underlying disinhibited, antisocial, and violent behavior. Biosocial perspectives and treatment implications

This paper reviews the autonomic psychophysiological correlates of antisocial and aggressive behavior in children and adolescents, outlines a biosocial perspective, and draws implications for treatment and prevention. Findings of studies on resting skin conductance and heart rate indicate that antisocial individuals are characterized by underarousal; these findings suggest that aggressive children may be stimulation seekers who are relatively fearless. Autonomic underarousal also typifies infants and young children with a disinhibited temperament that is thought to be a predisposition to juvenile delinquency and adult aggressive behavior. Deficits in the orienting response, a measure of attention allocation, also predisposes to later antisocial and criminal behavior. Initial studies have shown that particularly high levels of orienting, arousal, and conditionability may protect against crime development in those predisposed to such an outcome. From a biosocial standpoint, it is hypothesized that the psychophysiological correlates of antisocial and violent behavior may be greatest in those from more benign home backgrounds where the psychosocial push forward is relatively weaker. Alternatively, early environmental stress may underlie autonomic underarousal and hyporeactivity in antisocial individuals. Finally, it is possible that biofeedback, in combination with a multimodal treatment program, may be one benign intervention technique that may increase arousal and reduce aggression in underaroused antisocial children.

High rates of violence, crime, academic problems, and behavioral problems in males with both early neuromotor deficits and unstable family environments

BACKGROUND

It is commonly assumed that individuals with both biological and psychosocial deficits are more likely to become criminal, but there is surprisingly little empirical support for this assumption. We test the hypothesis that a group with biosocial risk factors are more likely to develop behavioral and academic problems in adolescence and violent criminal offending in adult-hood compared with groups with only biological or only social risk factors.

METHODS

Hypotheses were tested on a sample of 397 male subjects, using obstetric and early neuromotor measures collected in the first year of life; family, social, demographic, and behavioral measures at age 17 to 19 years; and criminal data at 20 to 22 years of age.

RESULTS

Cluster analysis of the risk factors indicated a group with obstetric risk factors only, a group with poverty risk factors only, and a biosocial group with both early neuromotor deficits and unstable family environments. The biosocial group had more than double the adult violence, theft, and total crime rates of the other 2 groups and had significantly more behavioral and academic problems in adolescence.

CONCLUSIONS

When early neuromotor deficits and negative family factors cluster together, individuals are particularly likely to become criminal and violent compared with those with only poverty or only obstetric risk factors. Because this biosocial group accounted for 70.2% of all crimes committed in the entire sample, early interventions that tackle these deficits might significantly reduce violence.

Neuroanatomical bases of electrodermal hypo-responding: a cluster analytic study

Schizophrenics and other psychiatric patients have been found to have a high incidence of electrodermal hypo-responding. Different neural mechanisms may underlie hypo-responding in these groups. The present study utilized cluster analysis of magnetic resonance imaging (MRI) and electrodermal orienting data to examine the neuroanatomical correlates of electrodermal hypo-responding in 15 schizophrenics, 15 psychiatric controls (predominately affective disorders), and 15 normal controls. The number of electrodermal responses was recorded during a standard orienting paradigm. MRI scans were obtained, yielding area measures for the pre-frontal cortex and lateral ventricle-brain ratios (VBRs). The number of electrodermal orienting responses and the MRI measures were transformed into zeta-scores and entered into an agglomerative hierarchical cluster analysis, which yielded three clusters. A 3 x 3 Chi-square analysis revealed that the three clusters significantly differed according to diagnostic group. Analyses of variance (ANOVAs) revealed that the first two clusters had significantly fewer electrodermal orienting responses than the third cluster (predominately normals). Further, the first cluster (predominately schizophrenics) had significantly smaller frontal lobes than the other two clusters. Additionally, the three normals in the first cluster had relatively high levels of schizotypy. The second cluster (predominately affective disorders) had significantly larger VBRs than the other two clusters. Schizophrenics in the three clusters differed with respect to gender composition and positive symptoms. Thus, diminished pre-frontal area may underlie electrodermal hypo-responding in a subgroup of schizophrenics and schizotypals, while enlarged ventricles may underlie the same phenomenon in the affective disorders and another subgroup of schizophrenics.

High autonomic arousal and electrodermal orienting at age 15 years as protective factors against criminal behavior at age 29 years

OBJECTIVE

Nothing is known about biological factors that protect a predisposed individual from becoming criminal. This 14-year prospective study tested the hypothesis that antisocial adolescents who desist from crime by age 29 have greater physiological arousal and orienting than antisocial adolescents who become adult criminals.

METHOD

Physiological arousal and orienting were measured in 101 unselected 15-year-old male schoolchildren. Of these, 17 antisocial adolescents who desisted from adult crime (desistors) were matched on adolescent antisocial behavior and demographic variables with 17 antisocial adolescents who became criminal by age 29 (criminals), and 17 nonantisocial, noncriminal normal subjects.

RESULTS

Desistors had significantly higher electrodermal and cardiovascular arousal and higher electrodermal orienting than the criminal group.

CONCLUSIONS

This is the first study to report biological factors that protect against the development of criminal behavior. The findings suggest that individuals predisposed to adult crime by virtue of showing antisocial behavior in adolescence may be protected from committing crime by high levels of autonomic arousal and orienting.

The stability of inhibited/uninhibited temperament from ages 3 to 11 years in Mauritian children

Stability of inhibited/uninhibited temperament was assessed using 1,795 Mauritian children tested at ages 3, 8, and 11 years. Children were divided into uninhibited, middle, and inhibited groups at each age based on social behavior. Results indicated that, relative to uninhibited children (1) those inhibited at age 3 obtained larger inhibition scores at age 8 (p < .0001), (2) those inhibited at age 8 obtained larger inhibition scores at age 11 (p < .002), and (3) those remaining inhibited from ages 3 to 8 obtained larger inhibition scores at age 11 (p < .002). Relative to children who changed classification from ages 3 to 8, those remaining inhibited obtained larger inhibition scores (p < .05) and those remaining uninhibited obtained smaller inhibition scores (p < .015) at age 11. Inhibition scores tended to be higher in females by age 11. Results remained regardless of ethnicity. The results provide some support that inhibited/uninhibited temperament remains stable from ages 3 to 8 and may continue to age 11. The results suggest cross-cultural generalizability of these findings with implications regarding the development of anxiety disorders in the Mauritian population.

Cognitive and psychophysiological correlates of positive, negative, and disorganized symptoms in the schizophrenia spectrum

This study examined the cross-sectional and prospective relationships between cognitive and psychophysiological variables and positive, negative, and disorganized symptoms in 40 outpatients with diagnoses of schizophrenia or schizoaffective disorder. The results indicated that disorganized symptoms were related to deficits in auditory and visuomotor attentional processing, increased skin conductance orienting response, and lower stress reactivity. Negative symptoms were related to reduced resting heart rate, increased stress reactivity, and deficits in visuomotor processing. Prospective findings indicated that both the cognitive and heart-rate variables might be trait-related aspects of the negative symptoms, while the skin conductance, but not the cognitive, variables might be trait-related aspects of the disorganized symptoms. Positive symptoms were not related to any of the cognitive or psychophysiological variables.

P300 topography in Alzheimer's disease

This study assessed whether P300 scalp topography distinguished subjects with Alzheimer's disease (AD) from controls. Specifically, it was predicted that the AD group would show maximum P300 amplitude over frontal areas and the largest P300 reduction over parietal and left hemisphere areas. These hypotheses were tested using a standard auditory oddball paradigm to compare 26 AD subjects and 26 controls matched on age, sex, handedness, and education. P300 was measured at frontal, central, parietal, and occipital sites over left and right hemispheres and along the midline. Results revealed that the distribution of P300 was different for the two groups such that the controls manifested a maximum over parietal areas, whereas the AD subjects showed a maximum at frontal sites with the largest reductions in P300 over parietal areas. No hemispheric differences in P300 were found. These results are consistent with the hypothesis that P300 represents the activity of multiple neural generators that are differentially disrupted by the disease process.

Patterns of cognitive asymmetry and syndromes of schizotypal personality

The Schizotypal Personality Questionnaire, modeled on the nine components of DSM-III-R schizotypy, was administered to 122 medical students along with the Thayer Activation-Deactivation Adjective Checklist and the Warrington Recognition Memory Test for words and faces. Close affinities were found between a three-factor schizotypal personality structure and a three-syndrome model of schizophrenia. Different patterns of cognitive asymmetry (word-face discrepancy scores) were related to Active and Withdrawn syndromes as in schizophrenia, and were related to high activation and general deactivation differences as predicted. A prospective single case study showed that a face-word discrepancy before a first episode of schizophrenia accurately predicted a Withdrawn presenting syndrome. The consistency between syndromes of schizophrenia and schizotypal personality in a normal population suggests possible etiological links between the two, and it supports a dimensional view of psychosis and subclinical predispositions.

Birth complications combined with early maternal rejection at age 1 year predispose to violent crime at age 18 years

BACKGROUND

This study tests the bisocial interaction hypothesis that birth complications when combined with early maternal rejection of the infant predispose to adult violent crime.

METHODS

This hypothesis was tested using a cohort of 4269 consecutive live male births on whom measures of birth complications (age 0), early maternal rejection (age 1 year), and violent crime (age 18 years) were collected.

RESULTS

A significant interaction (P < .0001) between birth complications and early maternal rejection indicated that those who suffered both birth complications and early child rejection were most likely to become violent offenders in adulthood. While only 4.5% of the subjects had both risk factors, this small group accounted for 18% of all violent crimes. The effect was specific to violence and was not observed for nonviolent criminal offending.

CONCLUSIONS

To our knowledge, this is the first study to show that birth complications in combination with early child rejection predispose to violent crime. The findings illustrate the critical importance of integrating biological with social measures to fully understand how violence develops and also suggest that prenatal, perinatal, and early postnatal health care interventions could significantly reduce violence.

Selective reductions in prefrontal glucose metabolism in murderers

This study tests the hypothesis that seriously violent offenders pleading not guilty by reason of insanity or incompetent to stand trial are characterized by prefrontal dysfunction. This hypothesis was tested in a group of 22 subjects accused of murder and 22 age-matched and gender-matched controls by measuring local cerebral uptake of glucose using positron emission tomography during the continuous performance task. Murderers had significantly lower glucose metabolism in both lateral and medial prefrontal cortex relative to controls. No group differences were observed for posterior frontal, temporal, and parietal glucose metabolism, indicating regional specificity for the prefrontal deficit. Group differences were not found to be a function of raised levels of left-handedness, schizophrenia, ethnic minority status, head injury, or motivation deficits in the murder group. These preliminary results suggest that deficits localized to the prefrontal cortex may be related to violence in a selected group of offenders, although further studies are needed to establish the generalizability of these findings to violent offenders in the community.