The structure of schizotypy: relationships between neurocognitive and personality disorder features in relatives of schizophrenic patients in the UCLA Family Study

Schizotypal personality features and certain neurocognitive deficits have been shown to aggregate in the relatives of schizophrenic patients, supporting the view that both are likely to reflect genetic contributions to liability to schizophrenia. Within the relatives of schizophrenic patients, however, the interrelationships between these potential indicators of liability to schizophrenia are not well known. Using data from the UCLA Family Study, we examine the interrelationships between personality disorder symptoms and neurocognitive functioning in nonpsychotic first-degree relatives of schizophrenic patients. Factor analyses indicate that several dimensions of schizotypy can be identified. A neurocognitive dysfunction dimension includes loadings from measures of sequential visual conceptual tracking, rapid perceptual encoding and search, and focused, sustained attention as well as the rating of odd and eccentric behavior from schizotypal personality disorder. Other aspects of schizotypal personality disorder form separate positive schizotypy and negative schizotypy dimensions. These analyses support the view that schizotypy is multidimensional in relatives of schizophrenic patients and indicate that neurocognitive deficits in perception and attention are associated with particular schizotypal personality features.     

Empathy, social functioning and schizotypy

Whilst affective empathy is concerned with one's emotional response to the affective state of another, cognitive empathy refers to one's understanding of another's mental state, and deficits in both are believed to contribute to the social behavioral abnormalities associated with schizophrenia. The present study aimed to test whether individual differences in normally distributed schizotypal personality traits are related to cognitive and affective empathy, and whether any observed association between schizotypy and empathy mediates the relationship between schizotypy and (reduced) social functioning. Non-clinical volunteers (N=223) completed measures of schizotypal personality, cognitive and affective empathy, social functioning and negative affect. The results indicated that higher schizotypy was associated with reduced empathy, poorer social functioning and increased negative affect. Of the specific schizotypal dimensions (positive, negative and disorganized), only negative schizotypy was significantly associated with social functioning, and this relationship persisted even after controlling for negative affect. Further, affective empathy functioned as a partial mediator in this relationship. These data show that the relationship between negative schizotypy and social functioning is at least partially attributable to deficits in affective empathy.     

The dimensional structure of the Wisconsin Schizotypy Scales: factor identification and construct validity

The present study examined the factor structure underlying the Wisconsin Schizotypy Scales and the validity of these dimensions. Confirmatory factor analysis with 6137 nonclinical young adults supported a 2-factor model with positive and negative schizotypy dimensions. As predicted, the schizotypy dimensions were differentially related to psychopathology, personality, and social impairment. Both dimensions were related to schizotypal and paranoid symptoms. Positive schizotypy was uniquely related to psychotic-like experiences, substance abuse, mood disorders, and mental health treatment, whereas negative schizotypy was associated with negative and schizoid symptoms. Both dimensions were associated with poorer overall and social functioning, but negative schizotypy was associated with decreased likelihood of intimate relationships. The findings support the construct validity of a multidimensional model of schizotypy and the use of psychometric inventories to assess these dimensions.     

Relationship between positive and negative symptoms of schizophrenia and schizotypal symptoms in nonpsychotic relatives.

BACKGROUND: Continuous rather than categorical measures of psychopathology may provide greater statistical power to detect susceptibility loci for schizophrenia. However, it has not been established that the dimensions of schizophrenic symptomatology and personality traits in nonpsychotic individuals share etiological factors. We therefore sought to clarify the relationship between positive and negative symptoms of schizophrenic probands and dimensions of schizotypy in their first-degree relatives. METHODS: In the Roscommon Family Study, we examined the ability of positive and negative symptoms in probands to predict 7 factors of schizotypy in nonpsychotic relatives using regression analysis. These consisted of positive, negative, and avoidant symptoms; odd speech; suspicious behavior; social dysfunction; and symptoms of borderline personality disorder. We examined 3 proband groups: schizophrenia (n = 127); schizophrenia, simple schizophrenia, and schizoaffective disorder (n = 178); and all nonaffective psychoses (n = 216), and their nonpsychotic relatives (n = 309, 477, and 584, respectively). RESULTS: Positive symptoms in all nonaffective psychoses probands predicted positive schizotypy (beta = 0.1972, P =.0004), social dysfunction (beta = 0.0719, P =.0489), and borderline personality disorder symptoms (beta = 0.1327, P =.0084) in relatives, while negative symptoms predicted negative schizotypy (beta = 0.2069, P =.0002), odd speech (beta = 0.2592, P =.0001), suspicious behavior (beta = 0.2749, P =.0001), and social dysfunction (beta =.2398, P =.0002). Proband negative symptoms and borderline personality disorder symptoms in relatives in the schizophrenia, simple schizophrenia, and schizoaffective disorder group were inversely related (beta = -0.1185, P =.05). CONCLUSIONS: Positive and negative symptoms in schizophrenia predict corresponding schizotypal symptoms in relatives. This provides evidence that these schizophrenic symptom factors (1) are etiologically distinct from each other and (2) occur on an etiological continuum with their personality-based counterparts.     

Factor versus cluster models of schizotypal traits. II: relation to neuropsychological impairment.

Heterogeneity in cognitive performance in schizophrenia and schizotypy may be accounted for, by differences in predominant symptom presentation. However, studies have not demonstrated consistent relations between specific cognitive impairments and specific trait dimensions in either population. Studies of group differences, particularly those using groups defined by cluster analyses are rare, but suggest that the negative trait dimension is more associated with executive function deficits, positive trait dimension with memory and attentional difficulties, and the disorganized trait dimension with attention problems. The present study examined the relation of schizotypal trait dimensions and executive function deficits in schizotypal individuals using two methods. Correlations between schizotypal factor scores and cognitive measures demonstrated that high negative symptoms were associated with poor performance on the WCST, while high scores on other trait dimensions were related to a better WCST performance. High scores in all trait dimensions were related to the na?ve rater's observations of unusual social behavior. A cluster analysis revealed three groups of schizotypals (predominantly negative presentation, predominantly positive symptom presentation, and high on all dimensions). The cluster with predominantly negative symptoms performed worse, than all other schizotypal groups and unselected controls, on the WCST and a higher percentage of them were rated as clinically impaired on the neuropsychological battery. However, schizotypals who were high on all trait dimensions were rated as having the most unusual social behavior by the na?ve raters. Overall, results support the hypothesis of a relation between executive function deficits and negative symptoms in schizotypal individuals.     

Facial affect recognition and schizotypal personality characteristics

Aim: Deficits in facial affect recognition are well established in schizophrenia, yet relatively little research has examined facial affect recognition in hypothetically psychosis‐prone or ‘schizotypal’ individuals. Those studies that have examined social cognition in psychosis‐prone individuals have paid little attention to the association between facial emotion recognition and particular schizotypal personality features. The present study therefore sought to investigate relationships between facial emotion recognition and the different aspects of schizotypy. Methods: Facial affect recognition accuracy was examined in 50 psychiatrically healthy individuals assessed for level of schizotypy using the Schizotypal Personality Questionnaire. This instrument provides a multidimensional measure of schizophrenia proneness, encompassing ‘cognitive‐perceptual’, ‘interpersonal’ and ‘disorganized’ features of schizotypy. It was hypothesized that the cognitive‐perceptual and interpersonal aspects of schizotypy would be associated with difficulties identifying facial expressions of emotion during a forced‐choice recognition task using a standardized series of colour photographs. Results: As predicted, interpersonal aspects of schizotypy (particularly social anxiety) were associated with reduced accuracy on the facial affect recognition task, but there was no association between affect recognition accuracy and cognitive‐perceptual features of schizotypy. Conclusions: These results suggest that subtle deficits in facial affect recognition in otherwise psychiatrically healthy individuals may be related to the vulnerability for interpersonal communication difficulties, as seen in schizophrenia.     

Factor versus cluster models of schizotypal traits. I: a comparison of unselected and highly schizotypal samples.

Factor analytic studies have long supported the division of schizophrenic symptoms into three relatively orthogonal factors: positive symptoms, negative symptoms, and disorders of relatedness/disorganization. Similarly, factor analyses of schizotypy often yield three factors: positive symptoms, negative symptoms, and social anxiety or disorganization. Recent cluster analyses, however, suggest that not all patients can be simply categorized according to these factors. Cluster analyses of schizotypal symptoms tend to result in clusters of individuals who are low in all factors, high in more than one factor, or high predominantly in one factor. The present study sought to compare factor and cluster models of schizotypal symptoms, as measured by the SPQ, PAS, and MIS, in unselected individuals and highly schizotypal individuals. Consistent with prior research, factor analysis of a large unselected undergraduate sample yielded three factors: "positive", "negative", and "disorganized." Factor analysis of schizotypal undergraduates produced the same three factors, plus a fourth designated "paranoid thinking." In contrast, cluster analysis of the unselected sample yielded four clusters ("low schizotypy", "average schizotypy", and "high schizotypy", plus "positive/disorganized"). Cluster analysis of the schizotypal subsample produced four clusters: "low schizotypy", "positive", "negative" and "high schizotypy."     

Approche neurobiologique des traits tempéramentaux associés aux troubles de personnalité

Recent publications in the field of neurobiology related to personality disorders allow some consideration on the bidirectional relationship between genetically determined temperamental traits and environment, interactions observed in the normal development of personality during childhood and adolescence or on the contrary in the building of a disordered personality revealed at adulthood. Based on the review of studies about development of personality disorders in children, adolescents and adults, this article puts forward the interactive quality of relations between genetic background and environmental factors and proposes hypotheses concerning the role of temperament in the development of personality. Correlations between genes and environment (rGE) and interactions gene-environment (GxE) are examined. Bidirectional feedback between temperament and environment where individual temperamental characteristics determine environment selection or adjustment and not the opposite is an example of an interaction of evocative type. However, actual research designs face difficulties in the establishment of a causal link due to the multitude and complexity of involved factors linking personality traits with temperamental genetic markers. This might explain the emergence of an endophenotype concept as it has been used with autism. An endophenotype consists in a mesurable cognitive, neurophysiological or neurochemical variable expressing the genetic defect present before the onset of the illness. Some studies put forward possible endophenotypes for borderline, antisocial and schizotypal personality disorders. Longitudinal research has shown the predictive quality of externalized conduct disorders of childhood leading to antisocial and to a lesser extent borderline personality disorders in adulthood. Impulsivity and affective lability might be based on minor neurocognitive abnormalities, subclinical attention deficits and/or marked neuropsychological dimensions such as strong extraversion. Suboptimal serotoninergic regulation has been established in destructive impulsivity and suicidability. Abnormalities in the dopaminergic and noradrenergic systems might also be implicated but it remains unclear to what extent repeated trauma and abuse during childhood might modify the hypothalamic-pituitary-corticotropic axis in response to chronic stress and transform permanently the modulation of physiological and psychological reactions of these children to their perturbed environment. Researches on conduct disorders have also demonstrated the evocative interaction of a particular temperament with the environment responding to marked novelty seeking behaviour, hyperactivity, impulsivity and lack of proper physiological reaction to extreme stimuli. Lack of behaviour inhibition found in antisocial individuals is attributed to noradrenergic and serotoninergic abnormalities and neurocognitive deficits. The dimensional continuity of schizotypal personality to schizophrenia is well established and electrophysiological markers such as abnormal eye tracking movements, P300 evoked potentials, prolonged electrodermal reactions with cognitive disorganization and deficits in inhibition of attention to usual stimuli might be the future endophenotypical markers to schizophrenia susceptibility. Further studies on temperamental traits might lead to the identification of genetic markers as precursors to personality disorders.     

An integration of schizophrenia with schizotypy: identification of schizotaxia and implications for research on treatment and prevention

The liability to schizophrenia (schizotaxia) is associated with deficits in a variety of domains, including negative symptoms and neuropsychological deficits, even in the absence of psychosis or pre-psychotic prodromal symptoms. Conceptually, this view of schizotaxia is similar to negative schizotypy (i.e., schizotypal personality disorder minus the positive symptoms). It is broader than DSM-IV schizotypal personality disorder (SPD), however, in that more relatives of patients with schizophrenia show core symptoms of schizotaxia than meet the diagnostic criteria for SPD. Three lines of evidence support the validity of schizotaxia. First, evidence of concurrent validation was obtained by showing that schizotaxic subjects were more impaired than non-schizotaxic subjects on a variety of independent clinical scales. Second, schizotaxic subjects showed higher levels of negative symptoms on the Structured Interview for Schizotypy than non-schizotaxic subjects, but did not differ on positive symptoms. Third, subjects who met predetermined criteria for schizotaxia (i.e., negative symptoms and neuropsychological deficits) showed positive effects following treatment with low doses of risperidone (0.25-2.0 mg). Thus, clinical deficits in schizotaxia may be identifiable, and to a significant extent, reversible. Implications for the conception of schizotypy and the prevention of schizophrenia will be discussed.     

Attentional deficits in patients with schizophrenia and in their non-psychotic first-degree relatives

The aim of this study was to investigate whether non-psychotic relatives of schizophrenic probands have deficits in sustained attention as measured by the Continuous Performance Test, Identical Pairs version (CPT-IP) and whether such deficits are associated with negative schizotypal personality disorders. The study subjects were 23 schizophrenic probands, 45 of their first-degree relatives and 36 normal controls. For each subject, attention was assessed during five conditions (2 standard, 2 slow, 1 easy) of visual stimuli (numbers and shapes). Schizotypy status was determined with the physical anhedonia and social anhedonia scales of Chapman et al. (Chapman, L.J., Chapman, J.P., Raulin, M.L., 1976. Scales for physical and social anhedonia. Journal of Abnormal Psychology 42, 374-382). The CPT-IP sensitive index d' in the standard shape condition was significantly lower in schizophrenics and in their relatives than in controls. For all d' values, the percentage of impaired first-degree relatives was at an intermediate level between patients and control individuals. Furthermore, the schizophrenic probands made more random errors in the standard and in the slow number conditions than the other two groups. None of the schizotypy measures correlated with the CPT-IP deficits. These results suggest that spatial sustained attention deficit may be a vulnerability marker for schizophrenia; however, this deficit and the negative dimension of schizotypal personality disorders may be distinct traits.     

Personality disorder symptomatology and neuropsychological functioning in closed head injury

Despite an emerging literature characterizing the neuropsychological profiles of borderline, antisocial, and schizotypal personality disorders, relations between personality disorder traits and neurocognitive domains remain unknown. The authors examined associations among Millon Clinical Multiaxial Inventory-III personality disorder scales and eight neuropsychological domains in 161 patients referred for neuropsychological evaluation following closed head injury. Most personality disorder scales were associated with some decrement in cognitive function, particularly speeded processing, executive function, and language, while histrionic and narcissistic scales had positive relations with neuropsychological functioning. Results suggest that many personality disorder traits are related to neurocognitive function, particularly those functions subserved by frontal and temporal regions.     

Cerebellar and lobar blood flow in schizophrenia: a perfusion weighted imaging study

Accumulating evidence indicates that cannabis use may be a risk factor for schizophrenia (SZ), and chronic cannabis users score higher than non-users on measures of schizotypal personality traits. The purpose of the present study was to investigate the relations between normal personality, schizotypy, and cannabis use. Sixty-two chronic cannabis users and 45 cannabis-naïve controls completed a measure of normal personality, the NEO-Five Factor Inventory (NEO-FFI), and two measures of schizotypy, the schizotypal personality questionnaire (SPQ) and perceptual aberration scale (PAS). Substance use was assessed using the SCID I alcohol/drug module and a locally developed drug use questionnaire. On the NEO-FFI, users scored higher than controls on openness, but lower on agreeableness and conscientiousness, and endorsed greater schizotypy on the SPQ and PAS. Higher neuroticism predicted greater schizotypy in both groups, and, higher Extraversion predicted lower negative-syndrome schizotypy among users. Finally, duration of cannabis use was positively correlated with scores on the SPQ and PAS among users, suggesting a relation between overall cannabis use chronicity and schizotypy. These data show that cannabis users differ from non-users on dimensions of normal personality and schizotypy, and provide further evidence that cannabis use is associated with increased levels of psychosis-related personality traits.     

Schizotypal traits, obsessive-compulsive symptoms, and social functioning in adolescents

The relationship between self-reported social functioning, schizotypal traits, and obsessive-compulsive symptoms (OCS) was studied in a sample of 508 adolescents, of which 49.8% were male adolescents, with a mean age of 14.9 (SD, 1.6). The Schizotypal Personality Questionnaire-Brief, Maudsley Obsessive-Compulsive Inventory and Social Adaptation Self-evaluation Scale was administered. The results showed that schizotypal personality in adolescents consists of 4 factors (Interpersonal, Disorganized, Paranoia and Magical Ideation) which are associated with OCS in nonclinical populations. The canonical correlation analysis showed that schizotypal traits and OCS shared 18% of the variance. Social functioning was negatively related to schizotypal personality traits; however, no relationship was found between social functioning and OCS. The data highlight the overlap between schizotypal traits and OCS, as well as the deficits in self-reported social functioning in schizotypal subjects. Future studies should focus on the link between these 2 constructs and study in depth the role that social functioning may be playing.     

Neurocognitive correlates of schizotypy in first degree relatives of schizophrenia patients

We examined neurocognitive correlates of three dimensions of schizotypy in 63 healthy first degree relatives of schizophrenia patients. Neurocognitive measures of attention, verbal memory, and prefrontal functioning were combined with self-report and interview measures of schizotypy. State-psychopathology (anxiety and depression) was a strong predictor for positive schizotypy (PS) and negative schizotypy (NS). PS was slightly correlated to verbal long-term memory, therefore weakly supporting the hypothesis that temporal-limbic malfunctioning underlies PS. NS was not correlated to any prefrontal measure, and therefore no evidence was found for the hypothesis that prefrontal malfunctioning underlies NS. Disorganization schizotypy (DS) was strongly correlated to the false alarm variable of the Continuous Performance Test (CPT), probably supporting the hypothesis of orbitofrontal malfunctioning underlying DS. This correlational pattern of DS echoes closely two schizophrenia studies reporting a relationship between formal thought disorder and the false alarm CPT variable. This similarity, across schizophrenia and relatives samples, may be considered as evidence that false alarms on the CPT and (subtle) problems in goal directedness of thinking are indicators of a genetically determined vulnerability to schizophrenia.     

Neuropsychological function in obsessive-compulsive disorder: effects of comorbid conditions on task performance.

BACKGROUND: Neuropsychological testing reveals a pattern of impairment among patients with obsessive-compulsive disorder (OCD) which implicates the orbitofrontal region. Studies of neuropsychological function in OCD differ regarding performance deficits on classical tests of frontal executive function. In some studies, OCD patients did not demonstrate impaired performance on tests of executive function. However, other researchers have documented performance deficits among OCD patients on measures of executive function. Patients with OCD also exhibit performance deficits on tests of visual/spatial memory and verbal memory. Again, in some studies, OCD patients did not demonstrate impaired performance on tests of memory function. How can we account for the conflicting findings? One possibility is that performance deficits on tests of cognitive function are associated with comorbid conditions. In prior work, we observed that OCD patients who did poorly on executive function tasks obtained high scores on a measure of schizotypal personality. A second possibility is that executive function deficits among patients with OCD are associated with comorbid depressive symptoms. METHOD: In the present study, a comprehensive neuropsychological test battery was administered to patients with OCD and matched healthy control subjects. We also administered dimensional measures of schizotypal personality and depression to patients with OCD and controls. We conducted analyses of covariance (ANCOVA), with scores on measures of schizotypal personality and depression used as covariates. RESULTS: OCD patients demonstrated performance deficits on measures of delayed memory, response inhibition, alternation learning, and obtained significantly higher scores on measures of disinhibition, impulsivity, and temporolimbic symptoms; however, OCD patients did not exhibit impaired performance on tests of executive function and verbal fluency, and did not report a significantly greater number of dysexecutive symptoms, when coexistent depressive and schizotypal symptoms were taken into account. CONCLUSION: Findings are consistent with the contention that dysfunction of an orbitofrontal-limbic network underlies OCD.     

Do schizotypal symptoms mediate the relationship between genetic risk for schizophrenia and impaired neuropsychological performance in co-twins of schizophrenic patients?

BACKGROUND: Neurocognitive deficits and symptoms of schizotypal personality disorder are both elevated in the first-degree relatives of schizophrenic patients, but their relationship to each other and their potential common genetic source remain unclear. METHODS: Fifty unaffected co-twins of schizophrenic patients and 123 control twins were assessed with a neuropsychological battery and structured clinical interviews. RESULTS: Working memory was influenced by genetic risk for schizophrenia but not schizotypal symptoms. Nearly all other domains were influenced by schizotypy symptoms but only in the co-twins of schizophrenic patients. Schizotypy symptoms in the absence of a family history did not seem to be related to impaired neurocognitive functioning. CONCLUSIONS: Schizotypy symptoms in those with genetic risk for schizophrenia are associated with increased risk for cognitive deficits. Some neurocognitive deficits might covary with subpsychotic symptoms due to a shared genetic factor. Community-ascertained schizotypal individuals might not be appropriate for modeling underlying genetic risk for schizophrenia.     

Cognitive profiles of schizotypal dimensions in a community cohort: Common properties of differential manifestations

Introduction: Studies assessing the effects of schizotypal dimensions (i.e., positive, negative, and disorganized) on cognitive functions have yielded mixed findings. In the present study, we administered an extensive battery of cognitive tasks to a community sample and defined the schizotypal dimensions according to a more analytical four-factor model, whereby positive schizotypy is further divided into cognitive–perceptual and paranoid. Method: Two hundred healthy community participants were assessed for schizotypy with the Schizotypal Personality Questionnaire; assessment of cognitive functions included set shifting, working memory, processing speed, verbal fluency, attention switching, planning/problem solving, strategy formation, and abstract reasoning. Associations between cognitive tasks and schizotypy were examined with hierarchical multiple linear regressions. We also divided our subjects into groups based on whether or not their scores in the negative, positive, and cognitive–perceptual factors fell in the upper 10% of the scores of a large community normative sample in Greece and examined between-group differences. Results: Applying both dimensional and categorical approaches, we showed that (a) attention-switching impairment is a “core” deficit of both negative and paranoid schizotypy, (b) impaired working memory and set shifting are associated mainly with negative and to a lesser extent paranoid schizotypy, (c) paranoid schizotypy is associated with reduced performance in tasks requiring intact frontotemporal connectivity, and (d) cognitive–perceptual and disorganized schizotypy are not associated with any cognitive functions. Conclusions: Our findings further support the more analytical four-factor categorization of schizotypy and suggest that the discrepancies in the findings so far might be due to a more “generalized” definition of the schizotypal dimensions. They also add further in the early formulation of the profile of the high-schizotypal individuals seeking psychiatric help so that their overall management is directed towards a more targeted approach.     

Interactive decision-making in people with schizotypal traits: A game theory approach

Studies that have investigated whether deficits in social cognition observed in schizophrenia are also present in schizotypal individuals have largely been inconclusive, and none of these studies have examined social interactive behavior. Here, we investigated interactive decision-making behavior in individuals differing in the amount of schizotypal symptoms using tasks derived from Game Theory. In total 1691 undergraduate students were screened with the Schizotypal Personality Questionnaire-Brief version. We selected 69 people distributed across the full schizotypal continuum to participate in Ultimatum and Dictator Games in which they played against human and non-human, computer partners. The results showed that higher levels of schizotypal symptoms, particularly positive and disorganized schizotypy, were related to proposing higher offers to all partners. Additionally, the amount of interpersonal schizotypal symptoms was associated with an increased acceptance rate of very unfair offers from human partners, possibly reflecting a blunted emotional response to such offers. We conclude that positive and disorganized schizotypal symptoms are associated with less adequate bargaining behavior, similar to what has been recently observed in patients with schizophrenia. The observed similarities on Ultimatum Game behavior between patients with schizophrenia and individuals with more schizotypal symptoms contribute to the growing evidence that social cognitive deficits may represent a marker of vulnerability to schizophrenia.     

Higher prefrontal cortical thickness in high schizotypal personality trait

A model of schizophrenia-spectrum disorders hypothesized that schizotypy shares biomarkers with schizophrenia but due to protective factors such as a greater prefrontal cortex those individuals have a reduced vulnerability to schizophrenia. In contrast to previous studies exploring volumetric brain correlates of schizotypy focussing on clinical samples or relying on between-group comparisons we measured cortical thickness and correlated it with the expression of schizotypal personality traits in a mentally healthy sample. We acquired high-resolution MRI scans from 34 subjects and used FreeSurfer to model the grey-white and pial surfaces for each individual cortex in order to compute the distance between these surfaces to obtain a measure of cortical thickness. Differences in cortical thickness were correlated with positive and negative factors of schizotypy as assessed by means of the schizotypal personality questionnaire. We found a significant positive correlation between right dorso-lateral prefrontal cortex (DLPFC) and right dorsal premotor cortex/frontal eye fields (dPMC/FEF) and the total schizotypy score, between right DLPFC and the positive factor, and between right temporo-parietal junction and the negative factor of schizotypy. The volume of thalamus was negatively correlated with schizotypy. A significant negative correlation between thalamus volume and dPMC/FEF cortical thickness was observed. One may speculate that this finding is in line with the hypothesis of a compensatory role of greater prefrontal cortex in schizotypy in healthy populations.     

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.