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

Quantitative electroencephalography as a biomarker for proneness toward developing psychosis

The fully dimensional approach to the relationship between schizotypal personality traits and schizophrenia describes schizotypy as a continuum throughout the general population ranging from low schizotypy (LoS) and psychological health to high schizotypy (HiS) and psychosis-proneness. However, no biological markers have yet been discovered that reliably quantify an individual's degree of schizotypy and/or psychosis. This study aimed to evaluate quantitative electroencephalographic (qEEG) measures of power spectra as potential biomarkers of the proneness towards the development of psychosis in schizotypal individuals. The resting-state oscillatory brain dynamics under eyes-closed condition from 16 LoS and 16 HiS individuals were analysed for qEEG measures of background rhythm frequency, relative power in δ, θ, low-α, high-α, low-β, high-β and low-γ frequency bands, and the high-temporal cross-correlation of power spectra between low- and high-frequency bands observed by averaging signals from whole-head EEG electrodes. HiS individuals at rest locked the thalamocortical loop in the low-α band at a lower-frequency oscillation and displayed an abnormally high level of neural synchronisation. In addition, the high-α band was found to be positively correlated with both the high-β and low-γ bands unlike LoS individuals, indicating widespread thalamocortical resonance in HiS individuals. The increase of regional alpha oscillations in HiS individuals suggests abnormal high-level attention, whereas the pattern of correlation between frequency bands resembles the thalamocortical dysrhythmia phenomenon which underlies the symptomatology of a variety of neuropsychiatric disorders including schizophrenia. These qEEG biomarkers may aid clinicians in identifying HiS individuals with a high-risk of developing psychosis.

Neurological soft signs and psychometrically identified schizotypy in a sample of young conscripts

There is growing interest in the connection between neurological soft signs (NSS) and schizophrenia spectrum disorders such as schizotypal personality disorder. The association between NSS and schizotypy was investigated in a subgroup of 169 young healthy male military conscripts included in the Athens Study of Psychosis Proneness and Incidence of Schizophrenia. During their first 2 weeks in the National Basic Air Force Training Centre (T(1)-first assessment), subjects completed the Schizotypal Personality Questionnaire (SPQ), the Symptom Checklist-90-Revised (SCL-90-R), and the Raven's Progressive Matrices (RPM). Then, 2 years later (T(2)-second assessment), at the time of military discharge, they were tested for NSS with the Neurological Evaluation Scale (NES) and reevaluated with the SPQ, the SCL-90-R and additionally the Structured Clinical Interview for Personality Disorders (SCID-II) for the Diagnostic and Statistical Manual of Mental Disorders Third Edition, Revised (DSM-III-R). NSS were more prominent in conscripts with high schizotypy; scores on Sequencing of Complex Motor Acts (SCMA) and the "Other Soft Signs" (OSS) subscales were correlated with high schizotypy at both T(1) and T(2). Increased levels of SCMA as well as the total NSS score were correlated at both T(1) and T(2) with the interpersonal SPQ factor (reflecting negative schizotypy). The findings support the proposal that negative schizotypy might be associated with subtle neurodevelopmental abnormalities.

Magical ideation, schizotypy and the impact of emotions

Research indicates that emotions can interfere with basic cognitive functions such as attention and memory, and that schizotypal traits may be related to vulnerability to such interference, The schizotypal trait magical ideation, expressed as illogicality and tendencies to endorse peculiar or eccentric beliefs, has been reported to be related to impairments in social cognitive functioning as well risk for psychosis. This study examined the impact of emotionally arousing films on heart rate activity, affect ratings, and working memory. Participants were university students. Results indicated that high magical ideation scores were associated with impairments in short-term memory, higher post-film affect ratings, decreased clarity of affect awareness, and increased heart rate in response to emotionally arousing films. These results suggest that magical ideation may be an indicator of lower thresholds for arousal and increased vulnerability to disruption of cognitive processes by situations that elicit strong emotions.

A developmental increase in allostatic load from ages 3 to 11 years is associated with increased schizotypal personality at age 23 years

Although allostatic load has been investigated in mood and anxiety disorders, no prior study has investigated developmental change in allostatic load as a precursor to schizotypal personality. This study employed a multilevel developmental framework to examine whether the development of increased allostatic load, as indicated by impaired sympathetic nervous system habituation from ages 3 to 11 years, predisposes to schizotypal personality at age 23 years. Electrodermal activity to six aversive tones was recorded in 995 subjects at age 3 years and again at 11 years. Habituation slopes at both ages were used to create groups who showed a developmental increase in habituation (decreased allostatic load), and those who showed a developmental decrease in habituation (increased allostatic load). Children who showed a developmental increase in allostatic load from ages 3 to 11 years had higher levels of schizotypal personality at 23 years. A breakdown of total schizotypy scores demonstrated specificity of findings to cognitive-perceptual features of schizotypy. Findings are the first to document a developmental abnormality in allostasis in relation to adult schizotypal personality. The relative failure to develop normal habituation to repeated stressors throughout childhood is hypothesized to result in an accumulation of allostatic load and consequently increased positive symptom schizotypy in adulthood.

Resting EEG deficits in accused murderers with schizophrenia

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

The development of skin conductance fear conditioning in children from ages 3 to 8 years

Although fear conditioning is an important psychological construct implicated in behavioral and emotional problems, little is known about how it develops in early childhood. Using a differential, partial reinforcement conditioning paradigm, this longitudinal study assessed skin conductance conditioned responses in 200 children at ages 3, 4, 5, 6, and 8 years. Results demonstrated that in both boys and girls: (1) fear conditioning increased across age, particularly from ages 5 to 6 years, (2) the three components of skin conductance fear conditioning that reflect different degrees of automatic and controlled cognitive processes exhibited different developmental profiles, and (3) individual differences in arousal, orienting, and the unconditioned response were associated with individual differences in conditioning, with the influence of orienting increasing at later ages. This first longitudinal study of the development of skin conductance fear conditioning in children both demonstrates that children as young as age 3 years evidence fear conditioning in a difficult acquisition paradigm, and that different sub-components of skin conductance conditioning have different developmental trajectories.

Extinction memory is impaired in schizophrenia

BACKGROUND

Schizophrenia is associated with abnormalities in emotional processing and social cognition, which might result from disruption of the underlying neural mechanism(s) governing emotional learning and memory. To investigate this possibility, we measured the acquisition and extinction of conditioned fear responses and delayed recall of extinction in schizophrenia and control subjects.

METHODS

Twenty-eight schizophrenia and 18 demographically matched control subjects underwent a 2-day fear conditioning, extinction learning, and extinction recall procedure, in which skin conductance response (SCR) magnitude was used as the index of conditioned responses.

RESULTS

During fear acquisition, 83% of the control subjects and 57% of the patients showed autonomic responsivity ("responders"), and the patients showed larger SCRs to the stimulus that was not paired with the unconditioned stimulus (CS-) than the control subjects. Within the responder group, there was no difference between the patients and control subjects in levels of extinction learning; however, the schizophrenia patients showed significant impairment, relative to the control subjects, in context-dependent recall of the extinction memory. In addition, delusion severity in the patients correlated with baseline skin conductance levels.

CONCLUSIONS

These data are consistent with prior evidence for a heightened neural response to innocuous stimuli in schizophrenia and elevated arousal levels in psychosis. The finding of deficient extinction recall in schizophrenia patients who showed intact extinction learning suggests that schizophrenia is associated with a disturbance in the neural processes supporting emotional memory.

Social stratification, health, and violence in the very young

Inequalities in human social groups contribute in important ways to the initiation and perpetuation of violence. Because both social inequalities and interpersonal aggression emerge in early life, it is important to study their developmental origins in the collective and individual behavior of young children. As young as 2 years of age, children assemble stable, linearly transitive dominance hierarchies when brought together in novel social groups. Just as the consequences of socioeconomic status may be due in part to experiences of social ordering per se, subjective childhood experiences of occupying a lesser or greater position on a scale of social influence may similarly affect health, safety, and behavior in early development. Children's experiences with social ordering may represent a first, formative encounter with the hierarchical social relations that affect health and susceptibility to violence over the human lifespan. We have studied the health correlates of group stressors, dominance positions, and biobehavioral reactivity within cohorts of preschool children and semi free-ranging rhesus macaques. Social position is ascertained using naturalistic observations of critical dyadic events, and stress-reactivity is measured using assessments of behavioral and biological responses to standardized challenges. Outcome measures, including indicators of mental and physical health and interpersonal injuries, have been assessed--in the case of children--with parent- and teacher-report questionnaires, child self-report protocols, and frequent, objective physical examinations of the child and--in the case of rhesus monkeys--with daily observations of violence-related injuries. Results to date have suggested the following provisional conclusions: (1) Children and monkeys form stable, linearly transitive social hierarchies in which identifiable subgroups of individuals occupy dominant and subordinate social positions. (2) Individuals occupying subordinate positions within the social group show exaggerated adrenocortical and/or autonomic reactivity to challenge and disproportionate rates of chronic medical conditions or violent injuries. (3) Stress-reactivity, naturally occurring stressors, and social position are interactively predictive of rates of morbidity. Monkeys who displayed high biobehavioral reactivity sustained disproportionate numbers of violent injuries during a confinement stressor. Children who were high in the dominance hierarchy and low in reactivity showed significantly higher rates of externalizing mental health symptoms, while those who were in subordinate social positions and high in reactivity showed higher prevalences of internalizing symptoms. In conclusion, the prevention of youth violence--and other forms of early disorder--will require a deeper, developmental understanding of the "headwaters" of aggression and victimization in early childhood and a stronger accounting of how early social inequalities set trajectories toward healthy or disordered behavior.

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.

Development of skin conductance orienting, habituation, and reorienting from ages 3 to 8 years: A longitudinal latent growth curve analysis

Little is known about the development of the skin conductance orienting response (SCOR) in childhood. This longitudinal study examines the effects of age on initial SCOR, habituation, and reorienting. Skin conductance responses to nonsignal auditory stimuli were recorded from 200 male and female children at five different time points (ages 3, 4, 5, 6, and 8 years). Longitudinal latent growth curve analyses were used to determine the trajectory of each SCOR measure during this period. Results indicated that (a) initial SCOR is present at age 3, increases thereafter to peak at age 6, and then levels off, (b) habituation is absent at age 3, but becomes apparent at age 4 years and increases thereafter with increasing age, (c) SC reorienting is absent from ages 3 to 8, and (d) boys and girls do not exhibit different developmental trajectories. Results suggest that from age 3 to 8 years, the transition from the functionally immature to mature neural network underlying orienting and habituation is a continuous process and may be related to children's cognitive development during this period.

Schizotypal personality: neurodevelopmental and psychosocial trajectories

Schizotypal personality research holds the promise of critically important insights into the etiology and ultimate prevention of schizophrenia. This article provides a critical overview of diagnostic, developmental, demographic, psychosocial, genetic, neurodevelopmental, psychophysiological, neurochemical, neurocognitive, brain imaging, and prevention-treatment issues pertaining to this personality disorder. It is argued that genetic and early environmental influences act in concert to alter brain structure/function throughout development, resulting in disturbances to basic cognitive and affective processes that give rise to three building blocks of schizotypy-cognitive-perceptual, interpersonal, and disorganized features. Two clinical subtypes are hypothesized: (a) neurodevelopmental schizotypy, which has its roots in genetic, prenatal, and early postnatal factors, is relatively stable, has genetic affinity to schizophrenia, and may benefit preferentially from pharmacological intervention, and (b) pseudoschizotypy, which is unrelated to schizophrenia, has its roots in psychosocial adversity, shows greater symptom fluctuations, and may be more responsive to psychosocial intervention.

Event-related potential correlates of phasic and tonic measures of the orienting reflex

We examined putative central nervous system (CNS) indices of tonic and phasic aspects of the orienting reflex (OR) in a passive event-related potential (ERP) dishabituation paradigm. Pre-stimulus skin conductance level (SCL) and the subsequent skin conductance response (SCR) were used as tonic and phasic OR "yard-sticks", respectively. Their stimulus-response patterns were used to assess two ERP components: the tonic pre-stimulus contingent negative variation (CNV) and the subsequent phasic late positive complex (LPC). SCLs and SCRs derived from each trial of the first train presented were compatible with traditional OR studies. Across-train means were also derived for each of the four measures examined. Arousal changes, as indexed by the SCL, were weak in the CNV which showed an additional expectancy effect. The LPC showed a stimulus-response pattern across trials identical to that of the SCR. This study clarifies links between the traditional autonomic measures of the indifferent OR and its CNS correlates, and encourages an OR perspective and/or interpretation of ERP effects.

Children's skin conductance level and reactivity: are these measures stable over time and across tasks?

The stability of children's skin conductance level during baselines (SCL-B) and SCL reactivity (SCL-R) were examined longitudinally. During two laboratory sessions (T1 and T2), 2 years apart, children participated in procedures during which they were exposed to two stressors namely exposure to an audiotaped conflict between two adults, and a problem solving task. Children ranged in age between 6 and 13 years at T1. Measures of SCL-B and SCL-R during the two stressors were obtained. Findings illustrated the temporal stability of SCL-B and SCL-R to the star-tracing task over 2 years. Results also indicated stability in SCL-R to the two stressors (argument and problem-solving) examined within the same session at either T1 or T2. These results support the proposition that SCL-B and SCL-R constitute stable individual differences at the ages examined, and build on the scant longitudinal literature on psychophysiological development in children.

Fronto-limbic and autonomic disjunctions to negative emotion distinguish schizophrenia subtypes

Schizophrenia patients show a disconnection in amygdala-medial prefrontal cortex and autonomic arousal systems for processing fear. Concurrent functional magnetic resonance imaging [fMRI] and skin conductance recording were used to determine whether these disturbances are specific to fear, or present in response to other signals of danger. We also examined whether these disturbances distinguish a specific symptom profile. During scanning, 27 schizophrenia (13 paranoid, 14 nonparanoid) and 22 matched healthy control subjects viewed standardized facial expressions of fear, anger and disgust (versus neutral). Skin conductance responses [SCRs]were acquired simultaneously to assess phasic increases in arousal. 'With-arousal' versus 'without-arousal' responses were analysed using non-parametric methods. For controls, 'with-arousal' responses were associated with emotion-specific activity for fear (amygdala), disgust (insula) and anger (anterior cingulate), together with common medial prefrontal cortex [MPFC] engagement, as predicted. Schizophrenia patients displayed abnormally increased phasic arousal, with concomitant reductions in emotion-specific regions and MPFC. These findings may reflect a general disconnection between central and autonomic systems for processing signals of danger. This disjunction was most apparent in patients with a profile of paranoia, coupled with poor social function and insight. Heightened autonomic sensitivity to signals of fear, threat or contamination, without effective neural mechanisms for appraisal, may underlie paranoid delusions which concern threat and contamination, and associated social and interpersonal difficulties.

Arousal and Activation in a Continuous Performance Task

Abstract: The concepts of arousal and activation have had a confused history in Psychophysiology, and there is no widely accepted consensus on their usefulness in the field. This study aimed to explore whether these concepts could be separated in terms of their effects on the phasic Orienting Response (OR) and behavioral performance. We defined arousal at a particular time to be the energetic state at that time, reflected in electrodermal activity and measured by skin conductance level. Task-related activation was defined as the change in arousal from a resting baseline to the task situation. A continuous performance task was used with normal children. The magnitude of the mean phasic OR elicited by target stimuli was dependent on arousal, but not on task-related activation. Two performance measures (mean reaction time and number of errors) improved with increasing activation, but not with arousal. These data suggest the value of conceptualizing arousal and activation as separable aspects of the energetics of physiological and behavioral responding in future studies of attention, cognition, and emotion.

What does electrodermal activity tell us about prognosis in the schizophrenia spectrum?

Various dysfunctions in electrodermal activity (EDA) have been found in schizophrenic patients. The present paper reviews evidence that the electrodermal dysfunctions may carry prognostic information regarding subsequent symptoms, as well as social and occupational outcome. Although the findings are not entirely consistent, heightened electrodermal activity as indicated by frequent orienting responses to innocuous stimuli, elevated skin conductance level (SCL), and frequent non-specific skin conductance responses (NS-SCR) is most often associated with poor symptomatic, social, and occupational outcome in schizophrenic patients. There have been no studies that have directly examined electrodermal prognostic indicators in schizotypal individuals. However, high-risk studies suggest that heightened electrodermal activity may be prognostic of poor outcome in schizotypals as well. Thus, abnormally high electrodermal arousal and reactivity is predictive of poor outcome in at least some patients. The theoretical implications of these findings and directions for further research are briefly discussed.

Schizophrenia and schizotypal personality: a tribute to Peter H. Venables

Peter Venables made multiple contributions to the field of schizophrenia and schizotypy, most notably in the areas of psychophysiology, neurocognition, and assessment. On the 50th anniversary of the start of his research career in 1951, a conference on schizophrenia and schizotypy was held in his honor in Tuscany, Italy. This special edition encapsulates many of the presentations given at that meeting, covering the areas of neurodevelopment, assessment, genetics, psychophysiology, neurocognition, brain imaging, psychopharmacology, intervention, and prevention. A key theme of this special edition concerns the integration of schizophrenia and schizotypy research in a manner that will allow for a more comprehensive understanding of both of these disorders.