Integration and development in schizotypy research: an introduction to the special supplement

Relationship between theta/beta ratio and mind wandering in schizotypy

Negative association was found between the frontal theta/beta ratio and mind wandering in participants with high schizotypal traits, while no such association was found in participants with low schizotypal traits. These findings provide insights into the neural mechanism of mind wandering in individuals with high schizotypal traits.

Quantifying the effects of practicing a semantic task according to subclinical schizotypy

The learning ability of individuals within the schizophrenia spectrum is crucial for their psychosocial rehabilitation. When selecting a treatment, it is thus essential to consider the impact of medications on practice effects, an important type of learning ability. To achieve this end goal, a pre-treatment test has to be developed and tested in healthy participants first. This is the aim of the current work, which takes advantage of the schizotypal traits present in these participants to preliminary assess the test's validity for use among patients. In this study, 47 healthy participants completed the Schizotypal Personality Questionnaire (SPQ) and performed a semantic categorization task twice, with a 1.5-hour gap between sessions. Practice was found to reduce reaction times (RTs) in both low- and high-SPQ scorers. Additionally, practice decreased the amplitudes of the N400 event-related brain potentials elicited by semantically matching words in low SPQ scorers only, which shows the sensitivity of the task to schizotypy. Across the two sessions, both RTs and N400 amplitudes had good test-retest reliability. This task could thus be a valuable tool. Ongoing studies are currently evaluating the impact of fully deceptive placebos and of real antipsychotic medications on these practice effects. This round of research should subsequently assist psychiatrists in making informed decisions about selecting the most suitable medication for the psychosocial rehabilitation of a patient.

Finding normal-to-better neurocognitive indexes in individuals with schizotypal traits using a social role task

Schizophrenia patients make more errors and have longer reaction times (RTs) than healthy controls in most cognitive tasks. Deficits are also observed in subclinical participants having high scores on the schizotypal personality questionnaire (SPQ). They are accompanied by smaller amplitudes of the event-related brain potentials (ERPs) that index attention and semantic- and working-memory. These functions are thus thought to be impaired in individuals having various schizophrenia attributes (SzAs). Nevertheless, normal RTs were recently found in SzAs during a particular self-referential task where half of the stimuli were names of extraordinary social roles (e.g., genius). Each name (ordinary or extraordinary) was presented individually, and participants were asked to decide whether or not they would consider themselves performing the role at any moment of their lives. To further test an absence of cognitive deficits in this task, the ERPs elicited by names of social roles were also examined in 175 healthy participants. The absence of longer RTs in high- than in low-SPQs was replicated. Moreover, the ERPs of high SPQs had larger occipital N1s, larger P2s and larger occipital N400s than those of low SPQs while late positive potentials (LPPs) were of similar amplitudes. Such results are consistent with clinical observations of greater attention and faster processing of stimuli related to extraordinary/delusional beliefs. Further studies should test whether the cognitive deficits found in SzAs are due to the use of tasks and stimuli that are less within their focus of interest than within that of healthy controls.

The relationship between schizotypal traits and satisfaction with life among Chinese young adults: The mediating effect of trait anxiety and mind wandering

Schizotypal traits have been found to be negatively associated with satisfaction with life but the underlying mechanisms are not well understood. This study investigated the association between schizotypal traits and satisfaction with life and explored the mediating role of trait anxiety and mind wandering in the relationship between those two variables in a sample of Chinese young adults. One hundred and two individuals with high schizotypal traits and 104 individuals with low schizotypal traits were screened using the Schizotypal Personality Questionnaire. They completed a series of questionnaires including the Satisfaction with Life Scale, Trait Anxiety Inventory, and Mind Wandering Questionnaire. Results showed that: First, the high schizotypal trait group showed lower satisfaction with life, and higher trait anxiety and mind wandering frequency than the low schizotypal trait group. Second, the high schizotypal trait group, trait anxiety, and mind wandering negatively predicted satisfaction with life. Third, mediation analyses showed that all indirect effect paths in the mediation model were significant, that is, trait anxiety and mind wandering alone and together mediated the relationship between schizotypal trait group and satisfaction with life. In conclusion, high schizotypal trait is a risk factor for low satisfaction with life. The association between schizotypal traits and satisfaction with life was mediated by the combination of trait anxiety and mind wandering. This study has implications for improving life satisfaction in individuals with high schizotypal traits.

Does childhood trauma predict schizotypal traits? A path modelling approach in a cohort of help-seeking subjects

Schizotypy constitutes a susceptibility to beneficial and deleterious schizotypal traits, ranging from coping mechanisms to schizotypal personality disorder on a psychosis continuum. Growing evidence indicates a relationship between childhood adversity and trauma and schizotypy. However, the exact influence of childhood adversity and trauma on schizotypy and its relation to sex is not sufficiently understood. Therefore, we investigated sex-adjusted connections between childhood adversity and trauma subdomains (emotional/physical/sexual abuse, emotional/physical neglect) and positive (magical ideation, perceptual aberration) as well as negative schizotypy (physical/social anhedonia). In total, 240 outpatients of the Early Detection and Intervention Centre of the University Hospital Cologne were assessed with the Trauma and Distress Scale for childhood adversity and trauma and the Wisconsin Schizotypy Scales for schizotypy. Path analyses were performed to investigate sex-adjusted correlations. The well-fitting path model of the total sample linked emotional abuse to magical ideation (p = 0.03; SE = 0.20) and emotional neglect to social anhedonia (p = 0.01; SE = 0.26). In females, physical abuse predicted magical ideation (p = 0.01; SE = 0.33), while emotional neglect forecasted physical anhedonia (p = 0.03; SE = 0.34) and social anhedonia (p = 0.03; SE = 0.32). In males, sexual abuse predicted perceptive aberration (p = 0.04; SE = 0.19) and emotional abuse forecasted magical ideation (p = 0.03; SE = 0.27). Overall, the significance of sex-specific interrelations between trauma and schizotypy were highlighted. Magical ideation and perceptive aberration occurred prominently in the absence of negative and disorganized schizotypy, thus positive schizotypy could be discussed as a beneficial expression of coping with emotional, physical and sexual abuse. Furthermore, emotional neglect should be addressed particularly to prevent deleterious negative schizotypy in females.Trial registration number (20-1243), date of registration (May 19th 2020), retrospectively registered.

Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy

Schizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals).

Body-environment integration: Temporal processing of tactile and auditory inputs along the schizophrenia continuum

According to the dimensional approach to psychosis, there is a continuum from low schizotypy to schizophrenia patients. The temporal aspect of sensory processing seems to be compromised across such continuum, as suggested by different studies separately investigating unisensory or multisensory domains. Most of these studies have so far focused primarily on the temporal processing of visual and auditory stimuli, either in schizotypy or schizophrenia, while leaving the tactile domain and the integration of touch with other senses mostly unexplored. Given the relevance of body-related perceptual abnormalities for psychosis proneness, we aimed at filling this gap in the literature across two studies. We asked participants with increasing levels of schizotypy (study 1) and schizophrenia patients (study 2) to perform three simultaneity judgement tasks: a unimodal tactile task, a unimodal auditory task and a bimodal audio-tactile task. Each task allowed estimating a simultaneity range (SR), as a proxy of the individual tolerance to asynchronies in the tactile, auditory and audio-tactile domains, respectively. Results showed larger SRs as the level of schizotypy increases. Specifically, the linear effect of schizotypy levels on the audio-tactile task was stronger than on the auditory task, which in turn was greater than the effect on the tactile task (study 1). Differently, schizophrenia patients showed larger SRs than controls in all the three tasks (study 2). The current study is the first empirical investigation across the continuum from low schizotypy to schizophrenia of the tolerance to asynchronies in the processing of external (auditory) and body-related (tactile) inputs.

The association of striatal volume and positive schizotypy in healthy subjects: intelligence as a moderating factor

BACKGROUND

Schizotypy, a putative schizophrenia endophenotype, has been associated with brain-structural variations partly overlapping with those in psychotic disorders. Variations in precuneus structure have been repeatedly reported, whereas the involvement of fronto-striatal networks - as in schizophrenia - is less clear. While shared genetic architecture is thought to increase vulnerability to environmental insults, beneficial factors like general intelligence might buffer their effect.

METHODS

To further investigate the role of fronto-striatal networks in schizotypy, we examined the relationship of voxel- and surface-based brain morphometry and a measure of schizotypal traits (Schizotypal Personality Questionnaire, with subscores Cognitive-Perceptual, Interpersonal, Disorganised) in 115 healthy participants [54 female, mean age (s.d.) = 27.57(8.02)]. We tested intelligence (MWT-B) as a potential moderator.

RESULTS

We found a positive association of SPQ Cognitive-Perceptual with putamen volume (p = 0.040, FWE peak level-corrected), moderated by intelligence: with increasing IQ, the correlation of SPQ Cognitive-Perceptual and striatal volume decreased (p = 0.022). SPQ Disorganised was positively correlated with precentral volume (p = 0.013, FWE peak level-corrected). In an exploratory analysis (p < 0.001, uncorrected), SPQ total score was positively associated with gyrification in the precuneus and postcentral gyrus, and SPQ Disorganised was negatively associated with gyrification in the inferior frontal gyrus.

CONCLUSIONS

Our findings support the role of fronto-striatal networks for schizotypal features in healthy individuals, and suggest that these are influenced by buffering factors like intelligence. We conclude that protective factors, like general cognitive capacity, might attenuate the psychosis risk associated with schizotypy. These results endorse the idea of a continuous nature of schizotypy, mirroring similar findings in schizophrenia.

Role for Positive Schizotypy and Hallucination Proneness in Semantic Processing

Semantic processing underpins the organization of verbal information for both storage and retrieval. Deficits in semantic processing are associated with both the risk for and symptoms presented in schizophrenia. However, studies are mixed and could reflect the confounding effects of medication and symptom heterogeneity. Therefore, we considered whether two risk phenotypes, positive schizotypy and hallucinatory predisposition, present in the general population were associated with differential responding profiles for a semantic processing task. One hundred and eighty-three participants completed the Schizotypal Personality Questionnaire, Launay-Slade Hallucination Scale, National Adult Reading Test, a handedness measure, and a computerized semantic relatedness judgment task. Pairs of words were related through their dominant or subordinate meanings, or unrelated. Participants were divided into four groups using a mean split on cognitive-perceptual (positive) schizotypy and hallucination proneness. Significant differences between groups were found for reaction time on the semantic relatedness task, with the high cognitive-perceptual schizotypy groups responding significantly slower to all word pairs compared to their low scoring counterparts. There was some evidence that high hallucination proneness was associated with significantly faster reaction times which may reflect disinhibitive processes, however additional support is required. The results suggest that these two components of psychosis risk are associated with different patterns of responding to semantic processing. More diffuse activation of semantic information appeared to be associated with positive schizotypy, while those predisposed to hallucinations appeared to respond quicker. These results have significant implications in the re-conceptualization of hallucination proneness as distinct from positive schizotypy. Additional research is required to investigate the association between psychotic-like experiences separate from personality variables such as positive schizotypy and semantic processing.

Schizotypy and individual differences in peripersonal space plasticity

The space surrounding our body, defined as peripersonal space (PPS), is dynamically shaped by our motor experiences. For instance, PPS extends after using a tool to reach far objects. Several studies have demonstrated how PPS size varies across people, depending on different individual characteristics, including schizotypy. Coherently, narrower PPS boundaries have been reported among high schizotypal individuals and schizophrenia patients. However, little is known about the relationship between PPS plasticity and personality traits like schizotypy. To this purpose, the present study has investigated the individual PPS plasticity, after two different motor trainings, along the schizotypal continuum. Specifically, PPS plasticity was tested after using a tool (Experiment 1) and after the mere observation of another person using the same tool (Experiment 2). Indeed, previous evidence has shown that tool-use observation influences visual distance judgments, extending the representation of PPS. To date, however, there is no study investigating whether observation of tools action could also affect multisensory PPS tasks. Experiment 1 has shown that PPS boundaries extended after using the tool; on the other hand, Experiment 2 has revealed the absence of PPS expansion. Moreover, greater PPS expansion emerged in the relatively-low schizotypal group than in the relatively-high one, regardless of the type of motor training performed. The absence of PPS modulation after the observation task is discussed in relation to recent findings showing that intentional action and/or the goal of the action represent potentially crucial elements to trigger PPS plasticity. Finally, these new results extend previous evidence underlining a potential general functional alteration of PPS with the increase of schizotypal level.

Schizotypy, social stress and the emergence of psychotic-like states - A case for benign schizotypy?

Schizotypy is a personality-organisation related to schizophrenia-liability as well as the emergence of psychotic symptoms and psychotic-like experiences (PLEs) in non-schizophrenic individuals. It has been suggested that some non-schizophrenic individuals may exhibit PLEs frequently, but in a fashion that is not distressing but life-enhancing ("benign schizotypy"). In schizophrenia and at-risk individuals, however, psychotic symptoms are not only distressing, but also triggered stress. To further investigate questions of causality and examine how PLEs may present as distressing symptoms in some individuals and as benign experiences in others, we explored how schizotypy-facets moderated PLEs-variability under experimentally induced social stress.We performed a standardised social stress-paradigm in 107 healthy adults (77 female, 30 male; average age 22,5 years), measuring changes in psychometrically assessed PLEs and the moderation of changes under stress through positive, negative and disorganised schizotypy. Results suggest two discrete effects: On the one hand, individuals high in disorganised and negative schizotypy showed stress-dependent increases in PLEs; without added effects of positive schizotypy. On the other, individuals low in negative and disorganised schizotypy showed higher levels of PLEs solely as a function of positive schizotypy but not stress. We discuss these findings in light of the fully-dimensional model of schizotypy and hypothesize that PLEs in individuals high in schizotypy-facets suggested to convey risk-for-schizophrenia (negative and disorganised) may reflect qualitatively different entities than PLEs in individuals with low values in these facets, but high expressions of positive schizotypy ("happy schizotypes"). Additionally, we emphasize the importance of not overlooking the disorganised schizotypy-facet in related research.

Spirituality, dimensional autism, and schizotypal traits: The search for meaning

The relationships of spirituality with human social cognition, as exemplified in autism spectrum and schizophrenia spectrum cognitive variation, remain largely unstudied. We quantified non-clinical levels of autism spectrum and schizotypal spectrum traits (using the Autism Quotient and the Schizotypal Personality Questionnaire-Brief Revised) and dimensions of spirituality (using the Hardt Spirituality Questionnaire) in a large sample of undergraduate students. We tested in particular the hypothesis, based on the diametrical model of autism and psychosis, that autism should be negatively associated, and positive schizotypal traits should be positively associated, with spirituality. Our primary findings were threefold. First, in support of the diametric model, total Spirituality score was significantly negatively correlated with total Autism Quotient score, and significantly positively correlated with Positive Schizotypal traits (the Schizotypal Personality Cognitive-Perceptual subscale), as predicted. Second, these associations were driven mainly by opposite patterns regarding the Search for Meaning Spirituality subscale, which was the only subscale that was significantly negatively associated with autism, and significantly positively associated with Positive Schizotypal traits. Third, Belief in God was positively correlated with Positive Schizotypal traits, but was uncorrelated with autism traits. The opposite findings for Search for Meaning can be interpreted in the contexts of well-supported cognitive models for understanding autism in terms of weak central coherence, and understanding Positive Schizotypal traits in terms of enhanced salience.

Comorbid Personality Disorders in Individuals With an At-Risk Mental State for Psychosis: A Meta-Analytic Review

Increasing evidence shows that personality pathology is common among patients at clinical high risk (CHR) for psychosis. Despite the important impact that this comorbidity might have on presenting high-risk psychopathology, psychological functioning, and transition to full psychotic disorders, the relationship between personality syndromes and CHR state has received relatively little empirical attention. The present meta-analytic review aimed at 1) estimating the prevalence rates of personality disorders (PDs) in CHR individuals and 2) examining the potential role of PDs in predicting transition from CHR state to a full-blown psychotic disorder. The systematic search of the empirical literature identified 17 relevant studies, including a total of 1,868 CHR individuals. Three distinct meta-analyses were performed to provide prevalence estimates of PDs in the CHR population. The first and more comprehensive meta-analysis focused on any comorbid PD (at least one diagnosis), the second one focused on schizotypal personality disorder (SPD), and the last one focused on borderline personality disorder (BPD). Moreover, a narrative review was presented to define the predictive role of personality disorders in promoting more severe outcomes in CHR patients. The findings showed that the prevalence rate of personality disorders in CHR patients was 39.4% (95% CI [26.5%-52.3%]). More specifically, 13.4% (95% CI [8.2%-18.5%]) and 11.9% (95% CI [0.73%-16.6%]) of this clinical population presented with SPD and BPD, respectively. Finally, the studies examining the effects of baseline personality diagnoses on conversion to psychotic disorders showed contradictory and insufficient results concerning the potential significant impact of SPD. Conversely, no effect of BPD was found. This meta-analytic review indicated that the CHR population includes a large subgroup with serious personality pathology, that may present with attenuated psychotic symptoms conjointly with distinct and very heterogeneous personality features. These findings support the need for improved understanding of both core psychological characteristics of CHR patients and differentiating aspects of personality that could have relevant clinical implications in promoting individualized preventive interventions and enhancing treatment effectiveness.

Models of Schizotypy: The Importance of Conceptual Clarity

The observation of psychosis-like traits that resemble symptoms of schizophrenia and bipolar disorder, both among healthy relatives of psychotic patients and among the general population, can be traced to the early 20th century.1,2 These traits have since been described within various models of illness and health (ie, normal/abnormal personality, abnormal psychotic continua), each giving rise to concepts such as "schizotypy," "psychoticism," and "psychosis-proneness" that are not necessarily interchangeable, although their subtle distinctions are often overlooked. Historically, there have been 3 major models of schizophrenia-/psychosis-proneness, one of which is referred to as "taxonic" or "quasi-dimensional,"3,4 and 2 models that can be regarded as "fully dimensional,"5,6 as distinguished by the relationship that is proposed to exist between psychosis-proneness and the risk of clinical schizophrenia or other psychotic disorder. In this review, we outline the key assumptions of each model and its implications for research of psychosis in relation to mental illness and health and for the alternative models. We integrate historical concept development with current findings from various fields of research (eg, personality, neurobiology, and behavioral genetics) and highlight the remaining questions each model poses in relation to understanding the development of psychotic illness and the distribution of psychotic-like traits in the general population.

Enhancing Psychosis-Spectrum Nosology Through an International Data Sharing Initiative

The latent structure of schizotypy and psychosis-spectrum symptoms remains poorly understood. Furthermore, molecular genetic substrates are poorly defined, largely due to the substantial resources required to collect rich phenotypic data across diverse populations. Sample sizes of phenotypic studies are often insufficient for advanced structural equation modeling approaches. In the last 50 years, efforts in both psychiatry and psychological science have moved toward (1) a dimensional model of psychopathology (eg, the current Hierarchical Taxonomy of Psychopathology [HiTOP] initiative), (2) an integration of methods and measures across traits and units of analysis (eg, the RDoC initiative), and (3) powerful, impactful study designs maximizing sample size to detect subtle genomic variation relating to complex traits (the Psychiatric Genomics Consortium [PGC]). These movements are important to the future study of the psychosis spectrum, and to resolving heterogeneity with respect to instrument and population. The International Consortium of Schizotypy Research is composed of over 40 laboratories in 12 countries, and to date, members have compiled a body of schizotypy- and psychosis-related phenotype data from more than 30000 individuals. It has become apparent that compiling data into a protected, relational database and crowdsourcing analytic and data science expertise will result in significant enhancement of current research on the structure and biological substrates of the psychosis spectrum. The authors present a data-sharing infrastructure similar to that of the PGC, and a resource-sharing infrastructure similar to that of HiTOP. This report details the rationale and benefits of the phenotypic data collective and presents an open invitation for participation.

High Schizotypal Individuals Are More Creative? The Mediation Roles of Overinclusive Thinking and Cognitive Inhibition

Although a theoretical link between positive schizotypy and heightened creativity has been established in the literature, little empirical research has been conducted to examine the underlying cognitive processes that contribute to this association. In addition, previous studies found a negative relationship between positive schizotypy and cognitive inhibition; however, they often used the paradigm of latent inhibition. This study used the paradigm of prepotent response inhibition indicated by Stroop interference effect and examined the mediation effects of overinclusive thinking (OT) and cognitive inhibition on the creativity of schizotypal individuals. Two groups of low and high schizotypal individuals (N = 78) participated in the study. Each participant completed one OT task, one color-word Stroop task, three other executive functioning (EF) control tasks, and two creativity tasks. The results indicated that the high schizotypal group outperformed the low schizotypal group in the creativity tasks. They also exhibited higher OT as indicated by faster reaction time and higher cognitive inhibition as indicated by lower Stroop interference effect. Further, participant's levels of OT and cognitive inhibition partially mediated the relationship between schizotypy and creativity. The results were discussed under the context of schizotypy and creativity research and implications for rehabitation were further provided.

A positive-psychological intervention reduces acute psychosis-proneness

BACKGROUND

While individuals at ultra-risk for schizophrenia are characterized by high negative/disorganised but low positive schizotypy, schizophrenia patients are usually high in all three schizotypy facets. Thus, avoiding increases in positive schizotypy in ultra-high risk individuals may constitute of form of schizophrenia-prevention. A possible method of reducing positive schizotypy could be Positive-Psychological intervention (PI).

METHODS

We present results from 2 independent studies, including a 12-month follow-up from study 1, using an easy-to-perform intervention based on Positive Psychology to reduce positive schizotypy.

RESULTS

A PI can significantly and sustainably reduce positive schizotypy compared to a placebo-condition. Furthermore, our results show very high response-rates to said intervention, with responsiveness to the intervention increasing significantly with disorganised schizotypic traits.

CONCLUSIONS

As especially disorganised schizotypy is of relevance for the risk of transition from high benign schizotypy to schizophrenia and is found most closely associated to familial schizophrenia-risk and highly elevated in at-risk mental states, our results are encouraging. We suggest, thus, that positive psychology can not only reduce positive schizotypy, but may be increasingly useful with rising schizophrenia-risk and, thus, be worthy of further investigation regarding it potential in schizophrenia-prevention.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Enhanced mental imagery and intact perceptual organization in schizotypal personality disorder

According to a widely held view, psychotic disorders such as schizophrenia are characterized by a vague boundary between the perception of the external world and the inner imagery of persons, objects, and events. In this study, we addressed the perception-imagery debate in schizotypal personality disorder (SPD). Thirty individuals with SPD and 30 matched healthy subjects completed a lateral masking task. Participants were asked to detect a low-contrast Gabor patch flanked by two collinear Gabor masks. In the perceptual task, the masks were physically present, whereas in the imagery task, participants only imagined the masks. By applying a binocular rivalry paradigm, we also measured the imagery priming effect. Results revealed that, in the perceptual task, collinear masks similarly decreased contrast threshold in SPD and controls. In the imagery task, contrast threshold reduction (facilitation by the imagined masks) was more pronounced in SPD relative to the controls. In the binocular rivalry paradigm, individuals with SPD showed higher imagery priming effects as compared to healthy controls. Enhanced imagery was not related to schizotypal traits. These results indicate intact early visual perception and heightened imagery in SPD, which may be a trait marker of unusual experiences without psychotic disorganization.

Electrophysiological correlates of visual backward masking in high schizotypic personality traits participants

Visual backward masking is strongly deteriorated in patients with schizophrenia. Masking deficits are associated with strongly reduced amplitudes of the global field power in the EEG. Healthy participants who scored high in cognitive disorganization (a schizotypic trait) were impaired in backward masking compared to participants who scored low. Here, we show that the global field power is also reduced in healthy participants scoring high (n=25) as compared to low (n=20) in cognitive disorganization, though quantitatively less pronounced than in patients (n=10). These results point to similar mechanisms underlying visual backward masking deficits along the schizophrenia spectrum.

Spatiotemporal processing of somatosensory stimuli in schizotypy

Unusual interaction behaviors and perceptual aberrations, like those occurring in schizotypy and schizophrenia, may in part originate from impaired remapping of environmental stimuli in the body space. Such remapping is contributed by the integration of tactile and proprioceptive information about current body posture with other exteroceptive spatial information. Surprisingly, no study has investigated whether alterations in such remapping occur in psychosis-prone individuals. Four hundred eleven students were screened with respect to schizotypal traits using the Schizotypal Personality Questionnaire. A subgroup of them, classified as low, moderate, and high schizotypes were to perform a temporal order judgment task of tactile stimuli delivered on their hands, with both uncrossed and crossed arms. Results revealed marked differences in touch remapping in the high schizotypes as compared to low and moderate schizotypes. For the first time here we reveal that the remapping of environmental stimuli in the body space, an essential function to demarcate the boundaries between self and external world, is altered in schizotypy. Results are discussed in relation to recent models of 'self-disorders' as due to perceptual incoherence.

Normative data of the Magical Ideation Scale from childhood to adulthood in an Italian cohort

The assessment of schizotypy allows to identify people at risk to develop psychosis. For this purpose, psychometric tools have been developed, such as the Magical Ideation Scale (MIS). This scale investigates attenuated forms of thought transmission experiences, thought withdrawal and aberrant beliefs, related to positive schizotypy. This study aims at providing an Italian version of the MIS and its normative data in the general population from childhood to adulthood, being the first study evaluating subjects under 17year-old. The Italian MIS version was translated by three independent operators and administered to 1378 non-clinical participants, stratified into four age groups (i.e., 8-13, 14-17, 18-24 and 25-34). The unidimensionality of the scale was supported, and its internal consistency was satisfactory (i.e., ordinal Cronbach's αs ranging from 0.86 to 0.90 in different age groups), as well as test-retest reliability (i.e., 1-month ICC of 0.82 in a retested sub-sample). Normative data for the age groups were provided. Specific gender and age-related differences in MIS score were found, i.e. females scored higher than males in the 25-34 age group, which in general, as a group, scored lower than all the other age groups. This study provided evidence of reliability for the Italian version of the MIS in childhood and adolescence, for the first time, as well as in adulthood, showing specific gender and age effects in the early adult cohort.

Both harmful and (some) helpful behaviours from others are associated with increased expression of schizotypal traits

Negative treatment from others is related to elevated levels of trait schizotypy, signifying increased risk for psychosis, but associations with helpful behaviour have been much less studied. Using the Stereotype Content Model we tested the hypothesis that passive and active forms of help would be associated with increased and decreased expression of schizotypy, respectively. Schizotypal traits were assessed in students (N=631) using positive (Perceptual Aberration) and negative (Social Anhedonia) subscales of the Wisconsin Schizotypy Scales-Brief. Experiences of active (intentional) and passive (less deliberative) harm and help were assessed with the Behaviour from Intergroup Affect and Stereotypes Treatment Scale. As predicted, the results showed that experiences of passive help from others were associated with a 2-3 fold increase in scores on schizotypy scales, whilst reports of active help tended to be associated with a decrease in scores on these scales. Results also showed that increased reports of active and passive harm were associated with elevated scores on negative and positive schizotypy subscales, consistent with prior research. These findings, bridging research on social stereotyping and schizotypal personality, challenge the assumption that helpful behaviour from others is always beneficial for individuals with schizotypal traits who are at increased risk for psychosis.

Schizotypal personality questionnaire--brief revised (updated): An update of norms, factor structure, and item content in a large non-clinical young adult sample

This study updates and provides evidence for the dimensionality, reliability, and validity of a standard instrument for detection and measurement of schizotypy in non-clinical young adults. Schizotypy represents a set of traits on which both nonclinical and schizophrenia-spectrum populations vary meaningfully. These traits are linked to biological, cognitive, and social dimensions of serious mental illness (SMI), to clinical and subclinical variation in personal and social functioning, and to risk for SMI. Reliable and valid identification of schizotypal traits has important implications for clinical practice and research. Four consecutive independent samples of undergraduates were administered the SPQ-BR (N=2552). Confirmatory factor analyses suggested a minor item wording change improved reliability, and this Updated questionnaire was implemented for three-quarters of the sample (SPQ-BRU). A, single-order, nine-factor structure had acceptable psychometric properties. The best fitting second-order structure included four higher-order factors that distinguished Social Anxiety and Interpersonal factors. This differentiation was supported by differential relationships with treatment history. The Disorganized factor had the greatest unique relationship with personal and family treatment history. With few exceptions, factor loadings showed stability across samples. Overall, the higher-order and lower-order factors of schizotypy demonstrated reliability and convergent and discriminant validity; detailed psychometric data are presented in a supplement.