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

Negative and paranoid symptoms are associated with negative performance beliefs and social cognition in 22q11.2 deletion syndrome

AIMS

22q11.2 deletion syndrome (22q11.2DS) is a neurogenetic condition associated with an increased risk of developing schizophrenia. Previous studies have shown that negative symptoms represent the most specific clinical characteristic of psychosis in 22q11.2DS and are strongly associated with outcome. However, the psychological mechanisms associated with these symptoms in this population are poorly understood. In accordance with recent conceptualizations in the field of schizophrenia, the present study aims at investigating whether negative symptoms are associated with the presence of negative performance beliefs and cognitive deficits.

METHODS

Thirty-five participants with 22q11.2DS and 24 typically developing individuals aged between 11 and 24 years were included in the study. Self-reported schizotypal symptoms (cognitive-perceptual, paranoid, negative and disorganization symptoms) and dysfunctional beliefs (negative performance beliefs and need for approval) were assessed. Measures of processing speed, verbal memory, working memory, executive functioning and face recognition were also extracted from a broad cognitive evaluation protocol.

RESULTS

Adolescents with 22q11.2DS reported significantly higher score on the negative dimension of the Schizotypal Personality Questionnaire than controls, even when controlling for the influence of anxiety/depression and intellectual functioning. Negative and paranoid symptoms were associated with the severity of negative performance beliefs and lower face recognition abilities. Mediation analyses revealed that negative performance beliefs significantly mediated the association between face recognition and negative/paranoid symptoms.

CONCLUSIONS

These findings suggest that negative performance beliefs and basic social cognitive mechanisms are associated with negative and paranoid symptoms in individuals with 22q11.2DS. Implications for intervention are discussed in this article.

Emotion processing deficits in the different dimensions of psychometric schizotypy

Schizotypy refers to a personality structure indicating "proneness" to schizophrenia. Around 10% of the general population has increased schizotypal traits, they also share other core features with schizophrenia and are thus at heightened risk for developing schizophrenia and spectrum disorders. A key aspect in schizophrenia-spectrum pathology is the impairment observed in emotion-related processes. This review summarizes findings on impairments related to central aspects of emotional processes, such as emotional disposition, alexithymia, facial affect recognition and speech prosody, in high schizotypal individuals in the general population. Although the studies in the field are not numerous, the current findings indicate that all these aspects of emotional processing are deficient in psychometric schizotypy, in accordance to the schizophrenia-spectrum literature. A disturbed frontotemporal neural network seems to be the critical link between these impairments, schizotypy and schizophrenia. The limitations of the current studies and suggestions for future research are discussed.

The Factor Structure of the Schizotypal Personality Questionnaire in Undergraduate and Community Samples

The prevailing theoretical model of the Schizotypal Personality Questionnaire (SPQ) is a three-factor model based on subscale-level analyses. However, recent item-level factor analyses of the SPQ suggest a four- or five-factor model. To examine the factor structure of the SPQ and how this structure may differ between undergraduate and community samples, the authors conducted exploratory and confirmatory item-level factor analyses of this measure on undergraduate (N = 1,850) and community participants (N = 1,464). A clear three-factor solution was found in the community sample, whereas a somewhat equivocal four-factor solution was found in the undergraduate sample. Both structures displayed gender invariance. This is the first study to address the issues of undergraduate sample generalizability and gender invariance in an item-level exploratory factor analysis of the SPQ. Given the disparate findings in the samples, this study indicates the importance of using both community and undergraduate samples when examining the factor structure of the SPQ.

The Psychosis Continuum: Testing a Bifactor Model of Psychosis in a General Population Sample

Although the factor structure of psychosis continues to be debated by taxonomists, recent studies have supported a bifactor model consisting of a general psychosis factor and 5 uncorrelated symptom-specific factors. While this model has received support in clinical samples, it has not been tested at the general population level. Analysis was conducted on Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (N = 34 653). Twenty-two psychotic symptoms were used as observed indicators of psychosis. These items were chosen based on their conceptual similarity to the items used in a similar study based on clinical samples. Confirmatory factor analysis and confirmatory bifactor modeling were used to test a variety of competing models. The best fitting model consisted of a general psychosis factor that was uncorrelated with 5 specific factors: positive, negative, disorganization, mania, and depression. These findings suggest that the bifactor model can be extended to general population samples, supporting the continuity between clinical and subclinical psychotic experiences. Theoretical and practical implications are discussed.

Associations of differential schizotypal dimensions with executive working memory: A moderated-mediation analysis

BACKGROUND

Increased schizotypal traits are observed in a percentage of the general population and in the schizophrenia-spectrum and have been associated with impairments in working memory. In this study we examined the effects of four schizotypal dimensions [Negative (NegS), Paranoid (ParS), Cognitive-Perceptual (CPS), Disorganized (DiS)] on executive working memory (EWM), as mediated by set-shifting, planning and control inhibition. We also examined whether these associations are moderated by family-history of psychosis.

METHODS

Our sample consisted of 110 unaffected first-degree relatives of schizophrenia-spectrum patients and 120 control individuals. Schizotypy was assessed with the Schizotypal Personality Questionnaire. Participants were also tested with the Letter-Number Sequencing, Wisconsin Card Sorting, Stroop Color-Word and Stockings of Cambridge tasks. The effects of set-shifting, control inhibition and planning on the relationship between schizotypy and EWM were examined with mediation analyses. Moderated-mediation analyses examined potential moderating effects of group membership (unaffected relative/community participant).

RESULTS

All mediators were significant in the relationship between NegS and EWM. The effects of ParS were mediated only by set-shifting and planning. Planning and control inhibition were the only significant mediators on the effects of CPS and DiS on EWM, respectively. The moderated-mediation analyses revealed that these findings apply only in the community group.

CONCLUSIONS

We found that the effects of different schizotypal dimensions on EWM are mediated by other cognitive processes in individuals without personal/family history of psychosis. This is probably due to either more severe impairments in the cognitive processes of the relatives or restrictions in our sample and study-design.

Embrained drives to perform extraordinary roles predict schizotypal traits in the general population

Some personal drives correspond to extraordinary social roles. Given that behavioral strategies associated with such drives may conflict with those associated with ordinary roles, they could cause behavioral disorganization. To test whether they do so independent of the factors responsible for full-blown schizotypy and schizophrenia, these drives were assessed in the general population. Two hundred and nine healthy volunteers were individually presented with hundreds of names of social roles in experimental psychology conditions. The task of the participant was to decide whether or not (s)he would consider performing the role at any moment of his/her life. Schizotypal traits were measured with the schizotypal personality questionnaire (SPQ), and delusion-like ideations were assessed by the Peters et al. Delusion Inventory. Demographics and social desirability were controlled for. Participants accepting a greater percentage of extraordinary roles had higher SPQ scores. Among the three factors of the SPQ, disorganization was the one best predicted by those percentages. This correlation (r=0.40, P=7.2E−09) was significantly greater (Fisher Z-transform, P=0.003) than the correlation between the percentages of ordinary roles accepted and the SPQ scores (r=0.145, P=0.044). Reaction times revealed no suboptimal cognitive functioning in high accepters of extraordinary roles and further strengthened the drive hypothesis. Their acceptances of roles were done faster and their rejections took longer than those of low accepters (P=5E−12). Culturally embrained drives to do extraordinary roles could thus be an independent factor of the symptoms measured in the normality to schizophrenia continuum.

[Schizotypal Personality Questionnaire-Brief - Likert format: Factor structure analysis in general population in France]

INTRODUCTION

The main objective of the study was to explore the factorial structure of the French version of the Schizotypal Personality Questionnaire-Brief (SPQ-B) in a Likert format, in a representative sample of the general population. In addition, differences in the dimensional scores of schizotypy according to gender and age were analyzed. As the study in the general population of schizotypal traits and its determinants has been recently proposed as a way toward the understanding of aetiology and pathophysiology of schizophrenia, consistent self-report tools are crucial to measure psychometric schizotypy. A shorter version of the widely used Schizotypal Personality Questionnaire (SPQ-Brief) has been extensively investigated in different countries, particularly in samples of students or clinical adolescents, and more recently, a few studies used a Likert-type scale format which allows partial endorsement of items and reduces the risk of defensive answers.

METHOD

A sample of 233 subjects representative of the adult population from an urban area near Paris (Créteil) was recruited using the "itinerary method". They completed the French version of the SPQ-B with a 5-point Likert-type response format (1=completely disagree; 5=completely agree). We examined the dimensional structure of the French version of the SPQ-B with a Principal Components Analysis (PCA) followed by a promax rotation. Factor selection was based on Eigenvalues over 1.0 (Kaiser's criterion), Cattell's Scree-plot test, and interpretability of the factors. Items with loadings greater than 0.4 were retained for each dimension. The internal consistency estimate of the dimensions was calculated with Cronbach's α. In order to study the influence of age and gender, we carried out a simple linear regression with the subscales as dependent variables.

RESULTS

Our sample was composed of 131 women (mean age=52.5±18.2 years) and 102 men (mean age=53±18.1 years). SPQ-B Likert total scores ranged from 22 to 84 points (mean=43.6±13). Factor analysis resulted in a 3-factor solution that explained 47.7% of the variance. Factor 1 (disorganized; 10 items) included items related to "odd behavior", "odd speech", as well as "social anxiety", one item of "constricted affect" and one item of "ideas of reference". Factor 2 (interpersonal; 7 items) included items related to "no close friends", "constricted affect", and three of the items of "suspiciousness". Factor 3 (cognitive-perceptual; 5 items) included items related to "ideas of reference", "magical thinking", "unusual perceptual experiences" and one item of "suspiciousness". Coefficient α for the three subscales and total scale were respectively 0.81, 0.81, 0.77 and 0.88. We found no differences in total schizotypy and the three dimensions scores according to age and sex.

CONCLUSION

Factor analysis of the French version of the SPQ-B in a Likert format confirmed the three-factor structure of schizotypy. We found a pure cognitive perceptual dimension including the most representative positive features. As expected, "Suspiciousness" subscale is included in both positive and negative dimensions, but mainly in the negative dimension. Surprisingly, "social anxiety" subscale is included in the disorganized dimension in our analysis. The SPQ-B in a Likert format demonstrated good internal reliability for both total and subscales scores. Unlike previous published results, we did not find any influence of age or gender on schizotypal dimensions.

Chinese version of the Schizotypal Personality Questionnaire: Factor structure replication and invariance across sex

INTRODUCTION

The Schizotypal Personality Questionnaire (SPQ) is a self-report measure assessing symptoms of schizotypy. The SPQ has been used in both normative and clinical samples and has much theoretical and empirical support. A three-factor structure of the SPQ, derived on the basis of work in schizophrenia, consisting of Cognitive-Perceptual, Interpersonal, and Disorganized factors, has been well replicated. The present study aimed to (i) validate this three-factor structure in the Chinese version of the SPQ in a sample of individuals of Chinese ethnicity, and (ii) test for invariance across sex.

METHODS

A total of 209 (99 males) undergraduate university students (Mage  = 19.5, SD = 1.6) were administered the SPQ.

RESULTS

Confirmatory factor analysis indicated a better fit between the data and the three-factor model compared with a one-factor model. Multigroup confirmatory factor analysis also found strong measurement invariance across sex.

DISCUSSION

The current results add to a growing body of literature evidencing cross-cultural validity of the SPQ and its invariance across sex. Research and clinical implications of the current results are discussed.

Explanatory risk factors in the relations between schizotypy and indicators of suicide risk

Schizotypy has been linked to suicide risk, but it is not known whether established suicide-related risk factors mediate this relation. The aim of this study was to assess the mediating effects of depressive symptoms, social anxiety, self-esteem, and intimate disclosure in peer relationships in the relation between interpersonal schizotypy and suicide ideation or lifetime suicide attempts. This aim was tested in 590 young adults using a nonparametric bootstrapping procedure. After inclusion of the mediators, interpersonal schizotypy was no longer directly associated with either suicide ideation or lifetime suicide attempts. Depression and self-esteem mediated the relation between interpersonal schizotypy and suicide ideation. No variables mediated the relation between interpersonal schizotypy and lifetime suicide attempts, and there were no significant direct relations when mediators were included. Schizotypy appears to be a distal risk factor for suicidal behavior; assessing depressive symptoms and self-esteem may provide more proximal information about suicide risk, and may be targets for mitigating suicide risk in individuals with schizotypy.

Effect of theory of mind and peer victimization on the schizotypy-aggression relationship

Prior longitudinal studies have established the relationship between schizophrenia and violence. However, previous studies on aggression and schizotypal personality are scarce. The present study examines whether peer victimization mediates the relationship between schizotypy and reactive-proactive aggression, and whether theory of mind (ToM) moderates this mediation. Schizotypy, peer victimization, reactive-proactive aggression, and ToM were assessed in 237 undergraduates. Peer victimization mediated the relationship between schizotypy and reactive aggression. ToM moderated this mediation effect; although peer victimization partially explains the schizotypy–aggression relationship, higher ToM skills weakened the detrimental effect of schizotypy on peer victimization which in turn reduces reactive aggression. In contrast, the moderated mediation was not significant for the proactive aggression model. Findings help delineate the underlying mechanism of the relationship between schizotypy and aggression. It is suggested that aggression could be reduced by enhancing ToM skills, thereby reducing peer victimization and the resultant schizotypy.

Latent variable mixture modeling in psychiatric research--a review and application

Latent variable mixture modeling represents a flexible approach to investigating population heterogeneity by sorting cases into latent but non-arbitrary subgroups that are more homogeneous. The purpose of this selective review is to provide a non-technical introduction to mixture modeling in a cross-sectional context. Latent class analysis is used to classify individuals into homogeneous subgroups (latent classes). Factor mixture modeling represents a newer approach that represents a fusion of latent class analysis and factor analysis. Factor mixture models are adaptable to representing categorical and dimensional states of affairs. This article provides an overview of latent variable mixture models and illustrates the application of these methods by applying them to the study of the latent structure of psychotic experiences. The flexibility of latent variable mixture models makes them adaptable to the study of heterogeneity in complex psychiatric and psychological phenomena. They also allow researchers to address research questions that directly compare the viability of dimensional, categorical and hybrid conceptions of constructs.

Bifactor structure of the schizotypal personality questionnaire (SPQ)

The schizotypal personality questionnaire (SPQ) is used to characterize schizotypy, a complex construct helpful for the investigation of schizophrenia-related psychopathology and putative endophenotypes. The SPQ factor structure at item level has been rarely replicated and no study had tested a bifactor model of the SPQ so far. The unidimensional, the correlated, the second-order and the bifactor models of the SPQ were tested to evaluate whether the items converge into a major single factor defining the schizotypy-proneness of the participants, to be used for grouping purpose. Parallel principal component analysis (PCA) and confirmatory factor analysis (CFA) were used to determine the optimal number of factors and components in a cross-sectional, survey design involving 649 college students (males: 47%). The first-order, nine-subscale model was confirmed by CFA in the whole sample. The best evidence from parallel PCA in the training set was in favor of a two-factor model; the bifactor implementation of this model showed good fit in the subsequent CFA. Two main dimensions of positive and negative symptoms underlie schizotypy in non-clinical samples, entailing specific risk of psychosis. On a measurement level, the study provided support for the use of the total scores of the SPQ to characterize schizotypy.

The validity of the Schizotypal Personality Questionnaire in a Greek sample: Tests of measurement invariance and latent mean differences

BACKGROUND

The Schizotypal Personality Questionnaire (SPQ) is a widely used scale for measuring schizotypal characteristics modeled on DSM-III-R criteria for schizotypal personality disorder (SPD). The aim of this study was to examine the factorial structure of the Greek SPQ, its factorial invariance across gender and different age groups and possible gender and age group differences at latent mean level.

METHODS

Eight hundred sixty-five community participants completed the Greek version of the SPQ.

RESULTS

With regard to the factorial structure of the original first-order model, the results showed that a seven-factor model (sub-scales "no close friends" with "constricted affect" and "ideas of reference" with "unusual perceptual experiences" were combined) was replicated adequately. Furthermore, the second-order "paranoid" model provided also adequate fit. With regard to the factorial invariance of the SPQ across gender and age, the analysis revealed that both, the first- and second-order models showed measurement invariance (configural, metric and structural) across gender and age groups (17-35 vs. 36-70). Latent mean differences across gender and age groups were also found.

CONCLUSIONS

Based on these findings, we can conclude that the Greek version of the SPQ is a psychometrically sound instrument for measuring schizotypal characteristics and a useful screening tool for SPD across gender and age.

Impaired conscious memory in non-clinical schizotypy

INTRODUCTION

Impaired controlled and preserved/enhanced automatic memory processes have been reported in schizotypy. This memory pattern has been considered as a marker of vulnerability to schizophrenia. Our aim was to further explore this memory pattern in non-clinical schizotypy in order to determine which specific dimensions of schizotypy (i.e., positive, negative or disorganised), and more specifically which components of the dimensions, are most closely related to memory dysfunctions.

METHODS

Fifty-seven undergraduate students performed a category-production task. This was adapted for use with the process dissociation procedure in order to dissociate between automatic and controlled memory processes. The level of schizotypy was assessed using the Schizotypal Personality Questionnaire.

RESULTS

Regression analyses confirmed that controlled memory processes decreased as schizotypy increased. The positive factors (more specifically, the ideas of reference subscale) and disorganised factors (more specifically, the odd or eccentric behaviour subscale) were negatively correlated with the controlled memory processes.

CONCLUSIONS

Our study supports the idea that impaired controlled processes are an early cognitive marker of vulnerability to schizophrenia and confirm that the disorganised factor contributes the most to vulnerability to memory dysfunction. It also emphasises the importance of dissociating between each of the features characterising schizotypy rather than considering it as a whole.

The stability of schizotypy across time and instruments

Little is known about the stability of schizotypy across relatively long time periods and instrumentation. This study assesses the degree of stability between schizotypy and its three factor structure as assessed by the Survey of Attitudes and Experiences (SAE) at age 17, and the Schizotypal Personality Questionnaire (SPQ) at age 23. A sample of 678 at ages 17 and 23 years from a birth cohort in Mauritius were split into two random samples, with initial analyses on the first sample independently replicated on the second sample. Cognitive-perceptual, interpersonal, and disorganized factors at age 17 correlated from 0.28 to 0.32 with their respective factors at age 23. Total scores correlated 0.41 (d=0.90) across this six year time period and increased to 0.58 (d=1.42) after correcting for measurement error. Receiver operating characteristic (ROC) analyses showed an area under the curve value of 0.74, confirmed prediction over time. Findings on predictive validity were closely replicated in the second independent sample. In contrast, social anhedonia at age 17 was unrelated to interpersonal deficits at age 23. Results provide replicable support for the moderate stability of cognitive-perceptual, interpersonal, and disorganized schizotypy across time, instrumentation, and a period of rapid developmental change.

Association between processing speed and subclinical psychotic symptoms in the general population: focusing on sex differences

Evidence is growing that persons along the schizophrenia spectrum, i.e., those who also display subclinical psychotic symptoms, exhibit deficits across a broad range of neuropsychological domains. Because sex differences in the association between cognitive deficits and psychosis have thus far been mostly neglected, we believe that ours is the first study specifically focused upon those differences when examining the relationship between subclinical psychosis and processing speed. Using a sample of 213 persons from the general population from Zurich, Switzerland, psychotic symptoms were assessed with three different questionnaires including the Schizotypal Personality Questionnaire, an adaptation of the Structured Interview for Assessing Perceptual Anomalies, and the Paranoia Checklist. Processing speed was assessed with the WAIS digit-symbol coding test. Two higher-order psychosis domains were factor-analytically derived from the various psychosis subscales and then subjected to a series of linear regression analyses. The results demonstrate that in both men and women associations between subclinical psychosis domains and processing speed were weak to moderate (β ranging from -0.18 to -0.27; all p<0.05). However, we found no sex-differences in the interrelation of subclinical psychosis and processing speed (ΔR(2)<0.005; p>0.30). In conclusion, it appears that sex differences in psychosis manifest themselves only at the high end of the continuum (full-blown schizophrenia) and not across the sub-threshold range. The small magnitude of the effects reported herein conforms to the etiopathology of the disorder. Since schizophrenia and related disorders from the spectrum are assumed to be multifactorial diseases, it follows that many etiological components of small effect are involved.

The Chapman psychosis-proneness scales: Consistency across culture and time

The purpose of the present study was to examine the factor structure and the temporal stability of the Chapman psychosis-proneness scales in a representative sample of nonclinical Chinese young adults. The four psychosis-proneness scales evaluated were the Perceptual Aberration (PAS), Magical Ideation (MIS), revised Social Anhedonia (RSAS), and revised Physical Anhedonia (RPAS) scales. The sample consisted of 1724 young adults with a mean age of 18.8 years (S.D. = 0.84). The results of the confirmatory factor analyses indicated that the best fitting model was a two-factor model with positive schizotypy (PER and MIS) scales and negative schizotypy (RSAS and RPAS) scales. The data add to the growing literature indicating that the measurement of schizotypal traits is consistent across cultures. In addition, the results support the measurement invariance of the Chapman psychosis-proneness scales across time, i.e., there was ample evidence of test-retest reliability over a test interval of 6 months.

The concept of schizotypy - A computational anatomy perspective

Despite major progress in diagnostic accuracy and symptomatic treatment of mental disorders, there is an ongoing debate about their classification aiming to follow current advances in neurobiology. The main goal of this review is to provide a comprehensive summary of the put forward schizotypy concept that follows the needs for objective assessment of schizophrenia-like personality traits in the general population. We focus on major achievements in the field from the perspective of magnetic resonance imaging-based computational anatomy of the brain. Particular interest is devoted to overlapping brain structure findings in schizotypy and schizophrenia to promote a dimensional view on schizophrenia as extension of phenotype traits in the non-clinical general population.

Childhood trauma and schizotypy: a systematic literature review

BACKGROUND

Schizotypy is a complex concept, commonly defined as a genetic vulnerability to schizophrenia that falls on a continuum between healthy variation and severe mental illness. There is a growing body of evidence supporting an association between childhood trauma and increased psychotic experiences and disorders. However, the evidence as to whether there is a similar association with schizotypy has yet to be systematically synthesized and assessed.

METHOD

We conducted a systematic search of published articles on the association between childhood trauma and schizotypy in four major databases. The search covered articles from 1806 to 1 March 2013 and resulted in 17,003 articles in total. Twenty-five original research studies met the eligibility criteria and were included in this review.

RESULTS

All 25 studies supported the association between at least one type of trauma and schizotypy, with odds ratios (ORs) ranging between 2.01 and 4.15. There was evidence supporting the association for all types of trauma, with no differential effects. However, there was some variability in the quality of the studies, with most using cross-sectional designs. Individuals who reported adverse experiences in childhood scored significantly higher on positive and negative/disorganized schizotypy compared to those who did not report such experiences.

CONCLUSIONS

All forms of childhood trauma and other stressful events (e.g. bullying) were found to be associated with schizotypy, with especially strong associations with positive schizotypy. However, because of the methodological limitations of several studies and a lack of further exploration of different possible mechanistic pathways underlying this association, more research is required.

Assessing sub-clinical psychosis phenotypes in the general population--a multidimensional approach

Several studies have demonstrated that expression of a psychosis phenotype can be observed below the threshold of its clinical detection. To date, however, no conceptual certainty has been reported for the validity and reliability of sub-clinical psychosis. Our main objectives were to assess the prevalence rates and severity of various psychosis symptoms in a representative community sample. Furthermore, we wanted to analyze which latent factors are depicted by several currently used psychosis questionnaires. We also examined how those latent factors for sub-clinical psychosis are linked to psychosocial factors, normal personality traits, and coping abilities related to chronic stress. Most of the eight subscales from the Paranoia Checklist and the Structured Interview for Assessing Perceptual Anomalies had a very similar type of distribution, i.e., an inverse Gaussian (Wald) distribution. This supported the notion of a continuity of psychotic symptoms, which we would expect to find for continuously distributed symptoms within the general population. Sub-clinical psychosis can be reduced to two different factors - one representing odd beliefs about the world and odd behavior, and the other one representing anomalous perceptions (such as hallucinations). Persons with odd beliefs and behavior are under greater burden and more susceptible to psychosocial risks than are persons with anomalous perceptions. These sub-clinical psychosis syndromes are also related to stable personality traits. In conclusion, we obtained strong support for the notion that there is no natural cut-off separating psychotic illness from good health. Sub-clinical psychosis of any kind is not trivial because it is associated with various types of social disability.

The independence of schizotypy from affective temperaments--a combined confirmatory factor analysis of SPQ and the short TEMPS-A

Sparse evidence of a co-aggregation of the risk of schizophrenia and bipolar disorder provides support for a shared but nonspecific genetic etiology of bipolar disorder and schizophrenia. Temperaments are conceptualized as trait sub-syndromic conditions of major pathologies. This study set out to test the hypothesis of a continuum between schizotypy and affective temperaments versus the alternative hypothesis of their independence based on a cross-sectional, survey design involving 649 (males: 47%) college students. The short 39-item TEMPS-A and the SPQ were used as measures of the affective temperaments and of schizotypy, respectively. Confirmatory factor analyses were applied to a unidimensional model, to a standard correlate traits model, to second-order representations of a common latent structure, and to a bifactor model. Confirmatory bifactor modeling provided evidence against a complete independence of the dimensions subsumed by the affective and the schizotypal traits. The best solution distinguished between two sub-domains grouping positive symptoms and negative symptoms as measured by the SPQ subscales, and a sub-domain related to the affective temperaments as measured by the TEMPS-A. Limitations due to the use of subscales from two different tools should be taken into account.

Examination of the factor structure of the Schizotypal Personality Questionnaire among British and Trinidadian adults

Much debate in schizotypal research has centred on the factor structure of the Schizotypal Personality Questionnaire (SPQ), with research variously showing higher-order dimensionality consisting of two to seven dimensions. In addition, cross-cultural support for the stability of those factors remains limited. Here, we examined the factor structure of the SPQ among British and Trinidadian adults. Participants from a White British subsample (n = 351) resident in the UK and from an African Caribbean subsample (n = 284) resident in Trinidad completed the SPQ. The higher-order factor structure of the SPQ was analysed through confirmatory factor analysis, followed by multiple-group analysis for the model of best fit. Between-group differences for sex and ethnicity were investigated using multivariate analysis of variance in relation to the higher-order domains. The model of best-fit was the four-factor structure, which demonstrated measurement invariance across groups. Additionally, these data had an adequate fit for two alternative models: (a) 3-factor and (b) modified 4-factor model. The British subsample had significantly higher scores across all domains than the Trinidadian group, and men scored significantly higher on the disorganised domain than women. The four-factor structure received confirmatory support and, importantly, support for use with populations varying in ethnicity and culture.

The Melbourne assessment of Schizotypy in kids: a useful measure of childhood schizotypal personality disorder

Despite being identified as a high risk cohort for psychosis, there has been relatively little research on the clinical presentation and assessment of Schizotypal Personality Disorder (SPD) in childhood. The current study aimed to develop a measure of childhood SPD (Melbourne Assessment of Schizotypy in Kids (MASK)) and assess discriminant validity against another neurodevelopmental disorder, autism spectrum disorder (ASD). Sixty-eight children aged between 5 and 12 (21 SPD, 15 ASD, and 32 typically developing) and their parents were administered the MASK. The MASK is a 57-item semistructured interview that obtains information from the child, their parents, and the clinician. The results showed high internal consistency for the MASK and higher scores in the SPD group. A factor analysis revealed two MASK factors: social/pragmatic symptoms and positive schizotypal symptoms. Both factors were associated with SPD, while only the social/pragmatic factor was associated with ASD. Within the two clinical groups, a receiver operating characteristic curve showed that the MASK (cut-off score: 132 out of 228) was a good indicator of SPD diagnosis. These preliminary MASK findings were reliable and consistent and suggest that childhood SPD is characterised by complex symptomology distinguishable from ASD.

Schizotypal personality questionnaire: new sources of validity evidence in college students

Schizotypal traits represent the behavioral expression of vulnerability to psychosis in general population. Among the most widely used measurement instruments, we could find the Schizotypal Personality Questionnaire (SPQ) (Raine, 1991). However, some aspects of its psychometric quality have yet to be analyzed. The main goal of the present study was to gather new sources of validity evidence of the SPQ scores in non-clinical young adults. The final sample was made up of 1123 college students (M=20.3 years; S.D.=2.6). The study of the internal structure using exploratory factor analysis revealed that SPQ items were grouped in a theoretical structure of seven second-order factors. Confirmatory factor analyses showed that the four-factor model (Paranoid) displayed better goodness-of-fit indices than the other hypothetical dimensional models tested. More complex measurement models, such as those tested using second-order confirmatory factor analyses and Exploratory Structural Equation Modeling, also showed adequate goodness-of-fit indices. The reliability of the SPQ scores ranged from 0.80 to 0.91. A total of 11 items showed differential functioning by gender. Advances in psychosis phenotype measurement open up new horizons to understand the structure and content of schizotypy.

Neural mechanisms of smooth pursuit eye movements in schizotypy

Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty-one healthy participants [N = 19 low schizotypes, N = 12 high schizotypes (HS)] underwent functional magnetic resonance imaging at 3T with concurrent oculographic recording while performing a SPEM task with sinusoidal stimuli at two velocities (0.2 and 0.4 Hz). Behaviorally, a significant interaction between schizotypy group and velocity was found for frequency of saccades during SPEM, indicating impairments in HS in the slow but not the fast condition. On the neural level, HS demonstrated lower brain activation in different regions of the occipital lobe known to be associated with early sensory and attentional processing and motion perception (V3A, middle occipital gyrus, and fusiform gyrus). This group difference in neural activation was independent of target velocity. Together, these findings replicate the observation of altered pursuit performance in highly schizotypal individuals and, for the first time, identify brain activation patterns accompanying these performance changes. These posterior activation differences are compatible with evidence of motion processing deficits from the schizophrenia literature and, therefore, suggest overlap between schizotypy and schizophrenia both on cognitive-perceptual and neurophysiological levels. However, deficits in frontal motor areas observed during pursuit in schizophrenia were not seen here, suggesting the operation of additional genetic and/or illness-related influences in the clinical disorder.

Cross-cultural invariance of the factor structure of the Schizotypal Personality Questionnaire across Spanish and American college students

The main goal of this study was to examine the cross-cultural invariance of the factor structure of the Schizotypal Personality Questionnaire (SPQ) (Raine, 1991) in two large samples of Spanish and American young adults. The final sample was made up of 2313 college students (508 men, 22%). Their mean age was 20.5 years (S.D.=3.2). The results indicated that the Stefanis et al. (2004) four-factor model yielded the best goodness-of-fit indices compared to alternative models. Moreover, the results support configural, metric, and partial measurement invariance of the covariances of the SPQ across the two samples. The finding of measurement equivalence across cultures provides essential evidence of construct validity for the schizotypy dimensions and of the cross-cultural validity of SPQ scores. The finding of comparable dimensional structures in cross-cultural samples lends further support to the continuum model of schizotypy and schizophrenia spectrum disorders. Future studies should continue to examine the validity of scores on the SPQ and other schizotypy measures and their variation or consistency across cultures.

Dimensions of psychotic experiences among women in the general population

Full-information factor analysis of ordinal data was employed to determine the factorial structure of the responses of 31,822 adult Swedish women to the 20 "positive" psychotic experience items of the Community Assessment of Psychic Experiences (CAPE) questionnaire. Five separable but correlated trait dimensions were found, reflecting Paranoia, Grandiosity, Magical Thinking, Delusions, and Hallucinations. High scores on any dimension were associated with a higher probability of questionnaire-assessed lifetime major depressive episodes or generalized anxiety disorder, though Grandiosity was so only to a very small degree. Our results closely match previous findings among adolescents and young women, and demonstrate that psychotic experiences cannot be considered a single trait.

Genetics, cognition, and neurobiology of schizotypal personality: a review of the overlap with schizophrenia

Schizotypy refers to a set of temporally stable traits that are observed in the general population and that resemble the signs and symptoms of schizophrenia. Here, we review evidence from studies on genetics, cognition, perception, motor and oculomotor control, brain structure, brain function, and psychopharmacology in schizotypy. We specifically focused on identifying areas of overlap between schizotypy and schizophrenia. Evidence was corroborated that significant overlap exists between the two, covering the behavioral brain structural and functional as well molecular levels. In particular, several studies showed that individuals with high levels of schizotypal traits exhibit alterations in neurocognitive task performance and underlying brain function similar to the deficits seen in patients with schizophrenia. Studies of brain structure have shown both volume reductions and increase in schizotypy, pointing to schizophrenia-like deficits as well as possible protective or compensatory mechanisms. Experimental pharmacological studies have shown that high levels of schizotypy are associated with (i) enhanced dopaminergic response in striatum following administration of amphetamine and (ii) improvement of cognitive performance following administration of antipsychotic compounds. Together, this body of work suggests that schizotypy shows overlap with schizophrenia across multiple behavioral and neurobiological domains, suggesting that the study of schizotypal traits may be useful in improving our understanding of the etiology of schizophrenia.

Testing measurement invariance of the schizotypal personality questionnaire-brief scores across Spanish and Swiss adolescents

BACKGROUND

Schizotypy is a complex construct intimately related to psychosis. Empirical evidence indicates that participants with high scores on schizotypal self-report are at a heightened risk for the later development of psychotic disorders. Schizotypal experiences represent the behavioural expression of liability for psychotic disorders. Previous factorial studies have shown that schizotypy is a multidimensional construct similar to that found in patients with schizophrenia. Specifically, using the Schizotypal Personality Questionnaire-Brief (SPQ-B), the three-dimensional model has been widely replicated. However, there has been no in-depth investigation of whether the dimensional structure underlying the SPQ-B scores is invariant across countries.

METHODS

The main goal of this study was to examine the measurement invariance of the SPQ-B scores across Spanish and Swiss adolescents. The final sample was made up of 261 Spanish participants (51.7% men; M = 16.04 years) and 241 Swiss participants (52.3% men; M = 15.94 years).

RESULTS

The results indicated that Raine et al.'s three-factor model presented adequate goodness-of-fit indices. Moreover, the results supported the measurement invariance (configural and partial strong invariance) of the SPQ-B scores across the two samples. Spanish participants scored higher on Interpersonal dimension than Swiss when latent means were compared.

DISCUSSION

The study of measurement equivalence across countries provides preliminary evidence for the Raine et al.'s three-factor model and of the cross-cultural validity of the SPQ-B scores in adolescent population. Future studies should continue to examine the measurement invariance of the schizotypy and psychosis-risk syndromes across cultures.

Empathic accuracy and cognition in schizotypal personality disorder

Interpersonal dysfunction contributes to significant disability in the schizophrenia spectrum. Schizotypal Personality Disorder (SPD) is a schizophrenia-related personality demonstrating social cognitive impairment in the absence of frank psychosis. Past research indicates that cognitive dysfunction or schizotypy may account for social cognitive dysfunction in this population. We tested SPD subjects and healthy controls on the Empathic Accuracy (EA) paradigm and the Reading of the Mind in the Eyes Test (RMET), assessing the impact of EA on social support. We also explored whether EA differences could be explained by intelligence, working memory, trait empathy, or attachment avoidance. SPD subjects did not differ from controls in RMET, but demonstrated lower EA during negative valence videos, associated with lower social support. Dynamic, multimodal EA paradigms may be more effective at capturing interpersonal dysfunction than static image tasks such as RMET. Schizotypal severity, trait empathy, and cognitive dysfunction did not account for empathic dysfunction in SPD, although attachment avoidance is related to empathic differences. Empathic dysfunction for negative affect contributes to decreased social support in the schizophrenia spectrum. Future research may shed further light on potential links between attachment avoidance, empathic dysfunction, and social support.

Development of schizotypal symptoms following psychiatric disorders in childhood or adolescence

It was examined how juvenile psychiatric disorders and adult schizotypal symptoms are associated. 731 patients of the Department of Child and Adolescent Psychiatry of the University Medical Centre Utrecht, the Netherlands, with mean age of 12.1 years (SD = 4.0) were reassessed at the mean age of 27.9 years (SD = 5.7) for adult schizotypal symptoms using the Schizotypal Personality Questionnaire-Revised (Vollema, Schizophr Bull 26(3):565-575, 2000). Differences between 13 juvenile DSM categories and normal controls (n = 80) on adult schizotypal total and factor scores were analyzed, using (M)ANCOVA. Pervasive developmental disorders (PDD), attention deficit hyperactivity disorders (ADHD), deferred diagnosis, sexual and gender identity disorders and depressive disorders had higher SPQ total scores when compared to normal controls (p < 0.001). Higher levels of disorganized schizotypal symptoms were found for PDD, ADHD, and deferred diagnosis (p < 0.001). The same diagnostic groups showed higher level of negative schizotypal symptoms, which was likewise true for sexual and gender identity disorders, depressive disorders, disruptive disorders, and the category of 'Other conditions that may be a focus of clinical attention' (p < 0.001). No differences with normal controls were found for adult positive schizotypal symptoms (p < 0.110). The current findings are suggestive of the idea that psychiatric disorders in childhood or adolescence are a more general expression of a liability to schizophrenia spectrum pathology in future life. In addition, specific patterns of adult schizotypal symptomatology are associated with different types of juvenile psychiatric disorder.

Isn't it ironic? Neural correlates of irony comprehension in schizophrenia

Ironic remarks are frequent in everyday language and represent an important form of social cognition. Increasing evidence indicates a deficit in comprehension in schizophrenia. Several models for defective comprehension have been proposed, including possible roles of the medial prefrontal lobe, default mode network, inferior frontal gyri, mirror neurons, right cerebral hemisphere and a possible mediating role of schizotypal personality traits. We investigated the neural correlates of irony comprehension in schizophrenia by using event-related functional magnetic resonance imaging (fMRI). In a prosody-free reading paradigm, 15 female patients with schizophrenia and 15 healthy female controls silently read ironic and literal text vignettes during fMRI. Each text vignette ended in either an ironic (n = 22) or literal (n = 22) statement. Ironic and literal text vignettes were matched for word frequency, length, grammatical complexity, and syntax. After fMRI, the subjects performed an off-line test to detect error rate. In this test, the subjects indicated by button press whether the target sentence has ironic, literal, or meaningless content. Schizotypal personality traits were assessed using the German version of the schizotypal personality questionnaire (SPQ). Patients with schizophrenia made significantly more errors than did the controls (correct answers, 85.3% vs. 96.3%) on a behavioural level. Patients showed attenuated blood oxygen level-dependent (BOLD) response during irony comprehension mainly in right hemisphere temporal regions (ironic>literal contrast) and in posterior medial prefrontal and left anterior insula regions (for ironic>visual baseline, but not for literal>visual baseline). In patients with schizophrenia, the parahippocampal gyrus showed increased activation. Across all subjects, BOLD response in the medial prefrontal area was negatively correlated with the SPQ score. These results highlight the role of the posterior medial prefrontal and right temporal regions in defective irony comprehension in schizophrenia and the mediating role of schizotypal personality traits.

Mental disorders, religion and spirituality 1990 to 2010: a systematic evidence-based review

Religion/spirituality has been increasingly examined in medical research during the past two decades. Despite the increasing number of published studies, a systematic evidence-based review of the available data in the field of psychiatry has not been done during the last 20 years. The literature was searched using PubMed (1990-2010). We examined original research on religion, religiosity, spirituality, and related terms published in the top 25 % of psychiatry and neurology journals according to the ISI journals citation index 2010. Most studies focused on religion or religiosity and only 7 % involved interventions. Among the 43 publications that met these criteria, thirty-one (72.1 %) found a relationship between level of religious/spiritual involvement and less mental disorder (positive), eight (18.6 %) found mixed results (positive and negative), and two (4.7 %) reported more mental disorder (negative). All studies on dementia, suicide, and stress-related disorders found a positive association, as well as 79 and 67 % of the papers on depression and substance abuse, respectively. In contrast, findings from the few studies in schizophrenia were mixed, and in bipolar disorder, indicated no association or a negative one. There is good evidence that religious involvement is correlated with better mental health in the areas of depression, substance abuse, and suicide; some evidence in stress-related disorders and dementia; insufficient evidence in bipolar disorder and schizophrenia, and no data in many other mental disorders.

Schizotypal traits are associated with poorer identification of emotions from dynamic stimuli

Recent research suggests that the emotion recognition difficulties seen in schizophrenia may also be present to a lesser degree in non-clinical individuals who report attenuated expressions of schizophrenia-like symptoms (schizotypy). However, evidence in non-clinical samples primarily comes from studies employing static facial emotion tasks, and it is not clear whether poorer emotion recognition in schizotypy persists when people have access to a broader range of emotional cues more representative of typical face-to-face social interactions. A community sample of 151 adults completed measures of schizotypal traits, IQ, and a task that assessed emotion recognition using dynamic video-based stimuli. Global schizotypy and positive schizotypal traits were each associated with poorer emotion recognition. Negative schizotypy was not associated with emotion recognition overall, but was associated with errors in recognising positive emotions. It appears that poorer emotion recognition in schizotypy is not limited to single-channel stimuli, but can be seen even when multiple emotional cues are available. Thus, individuals with high levels of schizotypal traits, and positive features in particular, may have greater difficulty when it comes to 'reading' the emotions of others in everyday social interactions.

Effects of a small dose of olanzapine on healthy subjects according to their schizotypy: an ERP study using a semantic categorization and an oddball task

Delusions and hallucinations are often meaningful. They thus reveal abnormal semantic activations. To start testing whether antipsychotics act by reducing abnormal semantic activations we focused on the N400 event-related brain potential, which is elicited by meaningful stimuli, such as words, and whose distribution on the scalp is known to depend on the semantic category of these stimuli. We used a semantic-categorization task specially designed to reduce the impact of the variations of context processing across subjects' groups and a classical oddball task as a control. Healthy subjects were recruited rather than psychotic patients to ensure that the medication effects could not be secondary to a reduction of symptoms. These participants (n=47) were tested in a double-blind cross-over paradigm where the ERP effects of 2.5mg of olanzapine taken on the eve of the testing were compared to those of the placebo. The amplitudes of the N400s elicited by the target words were greater at anterior scalp sites in the half of the subjects having higher schizotypal scores. Olanzapine reduced these larger N400s and had no effect on the small anterior N400s of the half of the subjects with lower scores. These results are discussed as consistent with the idea that antipsychotics reduce abnormal activations of particular semantic representations. Further studies should thus be done to see if this reduction correlates with and predicts the decrease of psychotic symptoms in patients.

Positive and negative schizotypy are associated with prodromal and schizophrenia-spectrum symptoms

The present study examined the validity of psychometrically assessed positive and negative schizotypy in a study of 214 Spanish young adults using interview and questionnaire measures of impairment and psychopathology. Schizotypy provides a useful construct for understanding the etiology and development of schizophrenia and related disorders. Recent interview, laboratory, and experience sampling studies have supported the validity of psychometrically assessed positive and negative symptom dimensions. The present study expands on previous findings by examining the validity of these dimensions in a Spanish sample and employing a widely used interview measure of the schizophrenia prodrome. As hypothesized, the positive schizotypy dimension predicted CAARMS ultra high-risk or psychosis threshold status, and both dimensions uniquely predicted the presence of schizophrenia-spectrum personality disorders. Furthermore, positive schizotypy was associated with psychotic-like, paranoid, schizotypal, and mood symptoms, whereas negative schizotypy was associated with interview ratings of negative and schizoid symptoms. The schizotypy dimensions were also distinguished by their associations with self and other schemas. Positive schizotypy was associated with increased negative self and other schemas, whereas negative schizotypy was associated with decreased positive self and other schemas. The findings provide further construct validation of positive and negative schizotypy and support these dimensions as universal constructs.

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 Structure and Measurement Invariance of the Wisconsin Schizotypy Scales across Gender and Age

The Wisconsin Schizotypy Scales are among the most widely used instruments for the assessment of psychosis proneness. The main goal of the present work was to study the dimensional structure underlying the Revised Physical Anhedonia Scale (RPhA), the Revised Social Anhedonia Scale (RSAS), the Magical Ideation Scale (MIS) and the Perceptual Aberration Scale (PAS). It was also explored whether the dimensions underlying these scales were invariant across gender and age. The sample was made up of 710 university students with a mean age of 19.8 years (SD = 1.9). The results showed that the dimensional structure of the Wisconsin scales was similar to that found in previous studies, displaying a Positive dimension and a Negative dimension, the Social Anhedonia Scale being related to both dimensions. Moreover, the factor structure of the schizotypy scales was found to be invariant across participants' gender and age.

Schizotypal traits and neurocognitive functioning among nonclinical young adults

Neurocognitive deficits and their relationship with symptoms have been documented in schizophrenia and at-risk samples. Limited research has examined relationships of schizotypal traits with cognitive functioning among nonclinical samples. To expand this literature and elucidate a dimensional model of psychosis-proneness, we examined the relationship of schizotypal traits with estimated intellectual functioning, simple and complex attention/working memory, verbal fluency and visuospatial abilities in a nonclinical sample of 63 young adults. As hypothesized, aspects of neurocognition were more closely associated with negative (than positive or disorganized) schizotypal traits. For the total sample, poorer visuospatial performance was associated with more negative and overall schizotypal traits. The magnitude of the majority of findings was strengthened after controlling for depression and anxiety. No other findings were significant. Results partially support Meehl's (1962, 1990) view that processes underlying schizophrenia are expressed along a continuum. Findings suggest a relationship of schizotypal traits with neurocognition that is differentiated by trait dimensions, beyond the contribution of general psychiatric symptoms. Findings have implications for better understanding etiology and potential risk factors for psychosis. While sex distribution did not enable direct examination of sex effects, evidence in the field argues for continued exploration of differential patterns by sex.

The relationship between personality disorders and Axis I psychopathology: deconstructing comorbidity

The purpose of this review is (a) to study and systematically review the recent literature examining the co-occurrence and relationships between Axis I psychiatric disorders and Axis II personality disorders, specifically the six originally proposed for the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5, and (b) to consider the clinical utility of the current Axis I and Axis II approach in the DSM-IV-TR and apply findings to state a position on the issue of collapsing together Axis I and Axis II. Community surveys or prospective cohort studies were reviewed as a priority. Our review indicates that the associations between clinical disorders and personality disorders clearly varied within each disorder and across the six personality disorders. Our understanding has advanced, particularly related to the clinical utility of comorbidity, and there may be sufficient evidence to support moving borderline personality disorder to Axis I. However, it seems premature to conclude that comorbidity is best conceptualized by having all disorders in a single category or by deleting disorders so that comorbidity is reduced. Our review suggests some priorities for future research into comorbidity, such as including personality disorders in future multivariate comorbidity models.

The role of atypical semantic activation and stress in odd speech: implications for individuals with psychometrically defined schizotypy

BACKGROUND

Odd speech is a cardinal symptom of schizophrenia; however, little is known about the mechanisms that lead to this construct in schizophrenia or schizotypy, the estimated 10% of the population who exhibit traits presumed to reflect genetic liability to schizophrenia. The lack of research concerning specific mechanisms of odd speech represents an important knowledge gap. Here, our primary aim was to examine how atypical semantic activation (ASA) and stress are related to odd speech in individuals with psychometrically-defined schizotypy.

METHODS

We employed highly sensitive laboratory procedures to test whether significant differences in ASA exist between psychometric schizotypy (n = 45) and non-psychometric schizotypy (n = 26) groups. We also examined odd speech across four conditions that varied according to valence (pleasant, unpleasant) and arousal (high, low) and analyzed whether ASA mediates odd speech in schizotypy.

RESULTS

The psychometric schizotypy group demonstrated significantly increased ASA, in the large effect size range. They also demonstrated a significant increase in one odd speech condition and a trend level group by arousal interaction was observed. Our hypothesis that ASA mediates odd speech in schizotypy was not supported.

CONCLUSIONS

Individuals with psychometric schizotypy exhibit semantic activation that is similar to patients with schizophrenia, albeit in a milder form. This study also provides evidence that ASA is a potential endophenotype of schizophrenia. Future studies should further explore properties of odd speech and ASA. Suggested avenues include cognitive deficits, particularly working memory, exploring underlying mechanisms, and examining how these constructs affect individuals across the schizophrenia-spectrum.

Ethical issues relevant to the assessment of suicide risk in nonclinical research settings

BACKGROUND

Our laboratory recently confronted this issue while conducting research with undergraduate students at the University of Waterloo (UW). Although our main objective was to examine cognitive and genetic features of individuals with schizotypal personality disorder (SPD), the study protocol also entailed the completion of various self-report measures to identify participants deemed at increased risk for suicide.

AIMS AND METHODS

This paper seeks to review and discuss the relevant ethical guidelines and legislation that bear upon a psychologist's obligation to further assess and intervene when research participants reveal that they are at increased risk for suicide.

RESULTS AND CONCLUSIONS

In the current paper we argue that psychologists are ethically impelled to assess and appropriately intervene in cases of suicide risk, even when such risk is revealed within a research context. We also discuss how any such obligation may potentially be modulated by the research participant's expectations of the role of a psychologist, within such a context. Although the focus of the current paper is on the ethical obligations of psychologists, specifically those practicing within Canada, the relevance of this paper extends to all regulated health professionals conducting research in nonclinical settings.

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.

Measurement invariance of the Schizotypal Personality Questionnaire-Brief across gender and age

The purpose of this study was to examine the dimensional structure and measurement invariance of the Schizotypal Personality Questionnaire-Brief (SPQ-B) (Raine and Benishay, 1995) across sex and age in a representative sample of nonclinical adolescents and young adults. The sample consisted of 1789 adolescents and young adults (42.1% males), with a mean age of 17.1years (S.D.=2.9). The results indicated that the Likert version of the SPQ-B showed adequate psychometric properties (α total score 0.89). The schizotypal personality models that presented the best fit indices were Raine et al.'s (1994) three-factor model and Stefanis et al.'s (2004) four-factor model. In addition, the results support the measurement invariance of the SPQ-B across sex and age. When the latent means of the schizotypal dimensions were compared across sex and age, statistically significant differences were found. Consistent with previous literature, schizotypal personality is a multidimensional construct whose structure appears invariant across sex and age. Future studies should examine the invariance of schizotypal personality across cultures, as well as using the SPQ-B as a screening method in the general population to detect individuals at risk for schizophrenia-spectrum disorders, given its rapid and easy administration.

Schizotypal traits and depressive symptoms in nonclinical adolescents

The main goal of this study was to examine the relationship between schizotypal personality traits and depressive symptoms in a sample of nonclinical adolescents. The Schizotypal Personality Questionnaire-Brief (J Personal Disord 1995;9:346-355) and the Reynolds Depression Adolescent Scale (Reynolds WM. Reynolds Adolescent Depression Scale. Professional Manual. Odessa: Psychological Assessment Resources, Inc; 1987) were administered. The sample was made up of 1384 adolescents (48.6% boys), with a mean (SD) age of 15.7 (1.0) years. The results of the study indicate a high degree of overlap between schizotypal experiences and depressive symptoms at a nonclinical level. Canonical correlation between the Schizotypal Personality Questionnaire-Brief scales and the Reynolds Adolescent Depression Scale scales was 0.63, which represents 39.69% of the associated variance between the 2 sets of variables. Confirmatory factor analysis showed that the 4-dimensional model made up of the Positive, Interpersonal, Disorganized, and Depressive dimensions was that which best fit the data. Moreover, the dimensional structure underlying the schizotypal traits and depressive symptoms was found to be invariant across sex and age. These findings converge with data found in previous studies of both patients with schizophrenia and nonclinical adults and suggest that affective dysregulation is also present at a subclinical level. Future research should continue to make progress in the early detection of participants at risk of developing schizophrenia-spectrum disorders based on the early identification of these types of subclinical traits.

Heritability and longitudinal stability of schizotypal traits during adolescence

The study investigated the genetic and environmental etiology of schizotypal personality traits in a non-selected sample of adolescent twins, measured on two occasions between the ages of 11 and 16 years old. The 22-item Schizotypal Personality Questionnaire- Child version (SPQ-C) was found to be factorially similar to the adult version of this instrument, with three underlying factors (Cognitive-Perceptual, Interpersonal-Affective, and Disorganization). Each factor was heritable at age 11-13 years (h (2) = 42-53%) and 14-16 years old (h (2) = 38-57%). Additive genetic and unique environmental influences for these three dimensions of schizotypal personality acted in part through a single common latent factor, with additional genetic effects specific to both Interpersonal-Affective and Disorganization subscales at each occasion. The longitudinal correlation between the latent schizotypy factor was r = 0.58, and genetic influences explained most of the stability in this latent factor over time (81%). These longitudinal data demonstrate significant genetic variance in schizotypal traits, with moderate stability between early to middle adolescence. In addition to common influences between the two assessments, there were new genetic and non-shared environmental effects that played a role at the later assessment, indicating significant change in schizotypal traits and their etiologies throughout adolescence.

Schizotypal traits and N400 in healthy subjects

We examined whether correlations previously found between symptoms of schizophrenia patients and the amplitude of an event-related potential (ERP), the N400, could be also found between schizotypal experiences of healthy subjects and the N400. We chose a semantic categorization task previously used with patients. Schizotypal experiences were measured with the schizotypal personality questionnaire (SPQ). The effects of the other factors were controlled for when assessing the correlations between each SPQ factor and N400s. These correlations were assessed at each electrode site to see whether their distribution on the scalp follows that of the N400 effect. Disorganization and interpersonal scores were found to correlate with ERPs in the N400 time window, as previously reported for the comparable symptoms of patients. However, the scalp distribution of these correlations differed from that of the N400 effect.