Parental mental disorders and offspring schizotypy in middle childhood: an intergenerational record linkage study.

PURPOSE: To investigate relationships between distinct schizotypy risk profiles in childhood and the full spectrum of parental mental disorders. METHODS: Participants were 22,137 children drawn from the New South Wales Child Development Study, for whom profiles of risk for schizophrenia-spectrum disorders in middle childhood (age ~ 11 years) were derived in a previous study. A series of multinomial logistic regression analyses examined the likelihood of child membership in one of three schizotypy profiles (true schizotypy, introverted schizotypy, and affective schizotypy) relative to the children showing no risk, according to maternal and paternal diagnoses of seven types of mental disorders. RESULTS: All types of parental mental disorders were associated with membership in all childhood schizotypy profiles. Children in the true schizotypy group were more than twice as likely as children in the no risk group to have a parent with any type of mental disorder (unadjusted odds ratio [OR] = 2.27, 95% confidence intervals [CI] = 2.01-2.56); those in the affective (OR = 1.54, 95% CI = 1.42-1.67) and introverted schizotypy profiles (OR = 1.39, 95% CI = 1.29-1.51) were also more likely to have been exposed to any parental mental disorder, relative to children showing no risk. CONCLUSION: Childhood schizotypy risk profiles appear not to be related specifically to familial liability for schizophrenia-spectrum disorders; this is consistent with a model where liability for psychopathology is largely general rather than specific to particular diagnostic categories.

Developmental profiles of schizotypy in the general population: A record linkage study of Australian children aged 11-12 years.

OBJECTIVES: The detection of young people at high risk for psychotic disorders has been somewhat narrowly focused on overt symptom-based markers that reflect mild reality distortion (e.g., psychotic-like experiences), or prodromal syndromes that are proximal to psychosis onset. The concept of schizotypy represents a broader framework for investigating risk for schizophrenia (and other disorders) in childhood, before the onset of prodromal or overt symptoms. We sought to detect profiles of risk for psychosis (schizotypy) in a general population sample of 22,137 Australian children aged 11-12 years, and to determine early life risk factors associated with these profiles from data available in linked records (registers). METHODS: Fifty-nine self-reported items were used as indicators of schizotypy across six broad domains; z-scores for each domain were subjected to latent profile analyses (LPA). A series of multinomial logistic regressions was used to examine the association between resulting profile (class) membership and several childhood and parental risk factors, and the proportion of children with mental disorders among each schizotypy profile was examined. RESULTS: The LPA revealed three person-centred profiles referred to as True Schizotypy (n = 1,323; 6.0%), Introverted Schizotypy (n = 4,473; 20.2%), and Affective Schizotypy (n = 4,261; 19.2%), as well as a group of children showing no risk (n = 12,080; 54.6%). Prior exposure to perinatal and familial adversities including childhood maltreatment, as well as poor early childhood development and academic functioning, was variously associated with all risk groups. There was a higher proportion of childhood mental disorder diagnoses among children in the True Schizotypy group, relative to other profiles. CONCLUSION: Subtle differences in the pattern of exposures and antecedents among schizophrenia liability profiles in childhood may reflect distinct pathogenic pathways to psychotic or other mental illness. PRACTITIONER POINTS: Children aged 11-12 years report characteristics of schizotypy which can be classified into three distinct profiles that may represent different pathological processes towards later mental ill-health. Early life exposure to perinatal and familial adversities including childhood maltreatment, early childhood developmental vulnerability, and poor academic functioning predict membership in all three childhood schizotypy profiles. Latent liability for schizophrenia (and potentially other mental disorders) may be represented by different profiles of functioning observable in childhood.

Aberrant salience and reward processing: a comparison of measures in schizophrenia and anxiety.

BACKGROUND: Aberrant salience may contribute to the development of schizophrenia symptoms via alterations in reward processing and motivation. However, tests of this hypothesis have yielded inconsistent results. These inconsistencies may reflect problems with the validity and specificity of measures of aberrant salience in schizophrenia. Therefore, we investigated relationships among measures of aberrant salience, reward, and motivation in schizophrenia and anxiety. METHOD: Individuals with schizophrenia (n = 30), anxiety (n = 33) or unaffected by mental disorder (n = 30) completed measures of aberrant salience [Aberrant Salience Inventory (ASI), Salience Attribution Test (SAT)], motivation (Effort Expenditure for Reward Task), and reinforcer sensitivity (Stimulus Chase Task). RESULTS: Schizophrenia participants scored higher than anxiety (d = 0.71) and unaffected (d = 1.54) groups on the ASI and exhibited greater aberrant salience (d = 0.60) and lower adaptive salience (d = 0.98) than anxious participants on the SAT. There was no evidence of a correlation between measures of aberrant salience. Schizophrenia was associated with related deficits in motivated behaviour and maladaptive reward processing. However, these differences in reward processing did not correlate with aberrant salience measures. CONCLUSIONS: The results suggest that key measures of aberrant salience have limited specificity and validity. These problems may account for inconsistent findings reported in the literature.

Narrative self and high risk for schizophrenia: remembering the past and imagining the future.

We examined the narrative self of those at high psychometric risk for schizophrenia (HR). Eighty undergraduate students wrote personal narratives about a turning-point event in their life, and about a possible future. The turning-point narratives were coded for topic, specificity, event valence, valence of causal coherence link, overall level of causal coherence, and agency. The future narratives were coded for the number and valence of goals, topic of goals, and specificity of goals. Word count was applied to all narratives. The HR group expressed lower levels of agency and a trend of lower levels of causal coherence when narrating turning-point events. When imagining their futures, HR participants produced shorter narratives and showed a trend of having fewer goals. Including the dimensions of both the turning point and the future narratives revealed that the HR group membership was best predicted by lower levels of agency and of causal coherence in the turning-point narrative, and fewer words in the future narrative. Narratives differed specifically in those few elements that are critical for the achievement of narrative continuity. Consistent with the theory, people at high risk for schizophrenia already present, to some extent, an impoverishment in their narrative sense of self.

Measurement invariance of brief forms of the Schizotypal Personality Questionnaire across convenience versus random samples.

Schizotypy, a multifaceted personality construct that represents liability for schizophrenia, is generally measured with self-report questionnaires that have been developed and validated in samples of undergraduate students. Given that understanding schizotypy in non-clinical samples is essential for furthering our understanding of schizophrenia-spectrum psychopathologies, it is critical to test whether non-clinically identified undergraduate and other convenience samples respond to schizotypy scales in the same way as random samples of the general population. Here, 651 undergraduates, 350 MTurk workers, and two randomly selected high school samples (n = 177, n = 551) completed brief versions of the Schizotypal Personality Questionnaire (SPQ-BR or SPQ-BRU). Multigroup confirmatory factor analysis was used to test whether measurement invariance was present across samples. Tests were made for all samples together and for each pair of samples. Results showed that a first-order nine-factor model fit the data well, and this factor structure displayed configural and metric invariance across the four samples. This suggests that schizotypy has the same factor structure, and the SPQ-BR/BRU is measuring the same construct across the different groups. However, when all groups were compared, results indicated a lack of scalar invariance across these samples, suggesting mean comparisons may be inappropriate across different sample types. However, when randomly selected high school students were compared with undergraduate students, scalar invariance was present. This suggests that factors such as culture and form type may be driving invariance, rather than sampling method (convenience vs general population).

Basic self-disturbance in schizotypy.

AIM: Phenomenological researchers argue that schizophrenia spectrum disorders are primarily disorders of the basic self. To test this argument, we compared self-report and lexical measures of basic self-disturbance between schizophrenia spectrum (high-schizotypy) and non-spectrum groups (low-schizotypy). METHODS: From an initial sample (n = 310) screened with the (SPQ), n = 39 were classified as high schizotypy (z > 1.28 on at least one SPQ factor scale) and were compared to a randomly selected low-schizotypy group (z < 1 on all three SPQ factor scales; n = 41). Participants wrote four narratives about personal and fictional experiences and completed the Ego Strength Questionnaire and a self-report version of the Schizophrenia Proneness Instrument. The written narratives were subjected to linguistic inquiry to examine pronoun usage (lexical measures). RESULTS: The high-schizotypy group reported higher levels of basic symptoms, lower ego strength, and used third-person and personal pronouns more frequently than the low-schizotypy group. Self-report measures correlated significantly with lexical measures. Self-report and lexical measures were useful tools in predicting high schizotypy, correctly classifying 68% and 69% of schizotypy and non-schizotypy, respectively. CONCLUSION: In line with phenomenologists' arguments, high schizotypy was associated, to some extent, with basic self-disturbance.

Longitudinal mediation by perceived burden of the pathway from thwarted belonging to suicidal ideation.

INTRODUCTION: Whereas the interpersonal theory of suicide entails the assumption that thwarted belongingness and perceived burdensomeness are equally important, mutually moderating, proximal causes of active ideation, evidence suggests these may not be co-moderating processes. We tested an alternative perspective, hypothesizing that burden mediates the longitudinal relationship of thwarted belonging with active ideation. METHODS: A 6-week, four-wave prospective online survey was completed by 298 undergraduates. We tested cross-sectional and cross-lagged panel models (CLPM, with and without random effects) with belonging, burden, and ideation at 2-week lags, and post hoc models with burden as a concurrent mediator of ideation. RESULTS: Approximately 28% of undergraduates reported active ideation at baseline. Cross-sectionally, thwarted belonging had no direct influence on ideation but indirectly affected ideation via burden. This result was not confirmed in the 2-week CLPM analyses. In post hoc analyses, we found belonging operated indirectly via later burden to influence contemporaneous ideation. CONCLUSIONS: Findings suggest thwarted belonging influences active ideation indirectly via perceived burden. The effect of burden as a mediator appears to depend on its temporal proximity to ideation. Future research should delimit the period during which perceived burden is an active mediator, accommodate dual-process approaches, and explore other mediation alternatives to co-moderation.

Psychotic Experiences and Schizotypy in Early Adolescence Predict Subsequent Suicidal Ideation Trajectories and Suicide Attempt Outcomes From Age 18 to 38 Years.

Subclinical risk markers for schizophrenia predict suicidality, but little is known about the nature of the relationship. Suicidal ideation is often considered homogenous, but distinguishing passive from active ideation (ie, thoughts of death vs thoughts of killing oneself) and different temporal patterns may further the understanding of risk factors. We tested whether schizotypy and psychotic experiences (PEs) in early adolescence predict subsequent growth trajectories of suicidal ideation and suicide attempt outcomes. Participants were 1037 members of the population-representative Dunedin Study cohort. PE was measured at 11 years and schizotypy at 13 and 15 years. Outcomes were passive and active suicidal ideation, and suicide attempt, measured at 18, 21, 26, 32, and 38 years. Passive ideation was best represented by 2 trajectories, including persistent and transient ideation classes. Schizotypy predicted membership in the smaller persistent class (odds ratio [OR] = 1.21, P = .041), whereas PE was not associated with class membership. The probability of suicide attempts was 13.8% in the persistent ideation class, compared with 1.8% in the transient class. Active ideation was best represented by a 1-class model, the intercept of which was predicted by schizotypy (OR = 1.23, P = .015). Suicide attempts were predicted by schizotypy (OR = 1.53, P = .040) and PE (OR = 3.42, P = .046), and this was partially mediated by indirect effects via the active ideation trajectory. Findings indicate that adolescent schizotypy and PE are related to subsequent suicidal ideation and attempts. Suicidal ideation is heterogeneous, and schizotypy is specifically related to a persistent passive ideation subgroup.

Systematic reviews of categorical versus continuum models in psychosis: evidence for discontinuous subpopulations underlying a psychometric continuum. Implications for DSM-V, DSM-VI, and DSM-VII.

Diagnostic systems, phenotype models, and theories of etiology incorporate propositions on the underlying nature of psychosis and schizophrenia phenotypes. These propositions, whether implicit or explicit, are that the distributions of the phenotypes, or the phenotype experiences themselves, are dimensional or categorical. On one hand, evidence on the epidemiology of schizophrenia phenotypes suggests symptom phenotypes may not be bound by conventional diagnostic thresholds but instead may blend imperceptibly with subclinical, statistically frequent experience, supporting continuum viewpoints. On the other hand, evidence on the population structure suggests a latent categorical structure; the population may be composed of two types of people. However, both sets of evidence are beset by methodological limitations that point unequivocally to the need to move beyond current diagnostic conceptualizations, observation, and anamnesis of psychosis, and toward responsive and scientifically refutable formulations of schizophrenia.

A comparison of delusions and overvalued ideas.

The relationship between delusions and overvalued ideas is uncertain, and has clinical as well as conceptual implications. This study aims to compare delusions and overvalued ideas on several characteristics that might further describe and distinguish them. A total of 24 individuals with delusions and 27 with overvalued ideas were recruited from a psychiatric service and assessed using a semistructured interview. Deluded individuals were less likely to identify what might modify their belief, less preoccupied, and less concerned about others' reactions than those with overvalued ideas. Delusions were less plausible and their onset less likely to appear reasonable. Delusions were more likely to have abrupt onset and overvalued ideas a gradual onset. Conviction and insight were similar in the 2 groups. Belief conviction and insight may be an inadequate basis for separating delusions from overvalued ideas. Abrupt onset, implausible content, and relative indifference to the opinions of others may be better distinguishing features.

Association of subclinical psychosis with suicidal ideation: A twin study.

Subclinical psychosis, including schizotypal indicators and psychotic experiences, predicts future suicidal ideation. This relationship may reflect unmeasured confounding from environmental factors, genetic factors, or both. We used a genetically-informative twin design to understand if the association between subclinical psychosis and suicidal ideation is independent of shared genetic and environmental factors. We analysed cross-sectional associations of age-22 self-reported subclinical psychosis (positive, negative, and disorganised features) with suicidal ideation in twins participating in the FinnTwin12 study (maximum n = 1213). Then, we analysed the reverse association of age-14 suicidal ideation with age-22 subclinical psychosis. Associations were studied first among individuals and then within monozygotic (MZ) and dizygotic (DZ) pairs. Individual-level analyses showed that all subclinical psychosis factors were associated with suicidal ideation. In within-pair analyses, estimates of associations were lower for MZ pairs than DZ pairs, except for the negative schizotypy-suicidal ideation association where estimates were consistent across individual-level and within-pair analyses. Findings provide evidence that the association between negative features and suicide ideation is not explained by familial factors and may be causal, though the possibility of confounding by individual-specific environmental factors and reverse causation cannot be ruled out. The relationships of positive and disorganised subclinical psychosis features with suicidal ideation cannot be explained by confounding due to environmental factors shared between siblings, but their associations may be due to shared genetic factors.

The burden of awareness of psychometric risk for schizophrenia.

Participants in studies of psychometric risk for schizophrenia are rarely informed of their risk status. Nondisclosure may be justifiable if the harmful effects of disclosure outweigh its benefits. We examined whether disclosure may adversely affect well-being and, if so, factors that predict the degree of adverse effect. Undergraduates (n=114) rated the anticipated impact--on felt distress, coping, optimism, helplessness, future lifestyle choices, and survival--of discovering they were at risk for schizophrenia and six other diseases. They also completed measures of potential predictors of this impact, including knowledge about schizophrenia, vicarious experience of schizophrenia, their potential to suffer stigmatization because of schizophrenia, and schizotypy. Participants judged schizophrenia risk more negatively than risk for heart disease, arthritis, depression, and diabetes, and less negatively than risk for cancer and Alzheimer's disease. Higher disorder-nonspecific impact, greater stigma, and lower psychometric risk for schizophrenia together provided the best linear prediction of schizophrenia-specific impact. Awareness of schizophrenia risk creates a significant adverse impact, the level of which may be greatest among those with lowest risk.

Components of schizophrenia liability affect the growth of psychological stress sensitivity following major life events.

BACKGROUND: Some argue that physiological and psychological stress sensitivities contribute causally to schizophrenia. Indeed, evidence shows that those with or at risk for schizophrenia have highly sensitive stress responses. However, it is unclear how psychological stress sensitivity develops. Our aim was to test whether psychological stress sensitization develops longitudinally in association with major life events and components of schizophrenia liability. We expected schizophrenia liability to predict higher psychological stress sensitivity; life events to predict subsequent increases in psychological stress sensitivity; and schizophrenia liability to moderate this relationship. METHODS: In a prospective study, undergraduates (n = 184) completed a measure of schizophrenia liability at baseline. Then at 2-month intervals over 6 months, they reported on the occurrence of major life events and completed measures of psychological stress sensitivity. RESULTS: Latent variable growth modelling showed that stress sensitivity increased following incident life events when controlling for baseline life events. Higher cognitive-perceptual and interpersonal scores predicted higher baseline sensitivity. Higher cognitive-perceptual features predicted larger increases in psychological stress sensitivity following life events whereas greater disorganization reduced growth. CONCLUSIONS: This evidence is consistent with the idea that psychological sensitization is involved in the development of schizophrenia and suggests an important link between positive features of schizophrenia liability and the magnification of psychological stress sensitivity.

Relationships between intra-individual variability and subclinical psychosis.

Extensive research indicates that elevated intra-individual variability (IIV) of reaction time is associated with subclinical psychosis, as well as clinically diagnosed psychotic disorder. However, findings regarding the details of this relationship are equivocal. In particular, it is unknown whether associations between elevated IIV and subclinical psychosis are specific to certain psychotic symptoms or to complex reaction time tasks. Data from 492 undergraduates from the University of Otago were used to address this issue. Schizotypy and psychotic-like experiences (PLE) were assessed via interview and questionnaire, and participants completed both a simple reaction time (SRT) task and a continuous performance task-identical pairs version (CPT-IP). The individual standard deviation and coefficient of variation (ICV) were used as measures of IIV. Participants reporting PLE were more likely to have elevated ICV on the CPT-IP. These associations were specific to paranoid psychotic experiences, and to the suspiciousness subscale of the Schizotypal Personality Questionnaire. There were also weak associations between SRT ICV and PLE. The inclusion of a battery of reaction time tasks assessing different aspects of cognitive control is suggested for future research, and the findings are discussed in relation to theoretical approaches to paranoia and delusions.

Intra-individual variability and psychotic-like experiences in adolescents: Findings from the ALSPAC cohort.

Clinical and epidemiological studies have demonstrated associations between elevated intra-individual variability (IIV) of reaction time and psychotic disorders. However, little attention has been paid to the relationship between performance stability and psychotic-like experiences (PLE) in adolescence, before psychotic disorder onset. Data from 6702 children from the Avon Longitudinal Study of Parents and Children (ALSPAC) were used to address this issue. Children took part in a semi-structured clinical interview regarding psychotic symptoms at age 12 and 18, and reaction time variability was assessed at age 13 and 15. Children who had elevated IIV at age 15 were more likely to report suspected or definite PLE at age 18, with larger associations being found for more frequent or bizarre symptoms. Elevated IIV at age 15 was also associated with persistent PLE between age 12 and 18. These findings tentatively suggest that elevated IIV in early adolescence may be predictive of later PLE, and offer some support for the notion of a psychosis continuum.

The Latent Taxonicity of Schizotypy in Biological Siblings of Probands With Schizophrenia.

If schizotypy is a taxonic liability for schizophrenia with a general population prevalence of ~10%, it should also be taxonic among biological siblings of probands with schizophrenia. Moreover, assuming this is so, siblings' schizotypy class membership should be predicted by probands' familial load for psychotic disorder and clinical severity, consistent with a multifactorial polygenic threshold model of schizophrenia. We tested these hypotheses in the Genetic Risk and Outcome of Psychosis (GROUP) Study where siblings of probands (n = 792) and unaffected controls (n = 559) provided self-report ratings on the Community Assessment of Psychic Experiences (CAPE). Maximum covariance analyses of control group ratings led to the identification of CAPE items sensitive to nonredundant positive and negative schizotypy classes in the control group (prevalence = 7.9% and 11.1%, respectively). When the same taxonic solution was applied to siblings' CAPE rating, taxometric analyses yielded evidence for larger positive and negative schizotypy classes among siblings (prevalence = 14.1% and 21.8%, respectively). Whereas probands' familial loads for bipolar disorder or drug use disorders did not predict siblings' membership in the schizotypy classes, probands' familial load for psychotic disorder did. Siblings were more likely to be members of the positive schizotypy class where their probands were more severely affected. The pattern of findings is consistent with Meehl's argument that schizotypy reflects liability for schizophrenia.

The relationships among aberrant salience, reward motivation, and reward sensitivity.

OBJECTIVES: Change in reward processing and motivation may mediate the relationship between dopaminergic dysregulation and positive symptoms of schizophrenia. We sought to investigate the measurement of aberrant salience and its relationship with behavioural measures of reward and motivation. METHODS: Participants (n = 82) completed measures of aberrant salience (Aberrant Salience Inventory and Salience Attribution Task), motivation (Effort Expenditure for Rewards Task), and reinforcer sensitivity (Stimulus Chase Task). Hypotheses were tested using correlation and generalised linear modelling. RESULTS: Results indicated no relationship between aberrant salience measures. The Aberrant Salience Inventory was positively related to effort expenditure for lower less likely rewards and predicted the use of probability alone in decision-making. The only significant relationship between reward and motivation was a positive relationship between gain sensitivity and motivated behaviour for higher more likely rewards. CONCLUSIONS: Although some support for a relationship between measures of reward motivation and aberrant salience were found, there was no evidence that the aberrant salience measures had concurrent validity. Our results suggest caution is warranted when interpreting measures of aberrant salience.

Components of schizophrenia liability are not uniformly associated with stress sensitivity, resilience, and coping.

Stress sensitization is a candidate final common pathway for the development of schizophrenia. In other psychopathologies, resilience attenuates the stressor-outcome relationships. Therefore, we sought to determine whether resilience moderates the association between stress sensitivity and schizophrenia liability. Undergraduates (n = 230) self-reported cognitive-perceptual, interpersonal, and disorganisation attributes of schizophrenia liability as well as ratings of sensitivity to stress, resilience, and dispositional coping behaviour. Bivariate analyses showed components of schizophrenia liability were significantly predicted by greater stress sensitivity, poor resilience and adaptive coping, and greater maladaptive coping behaviour. However, regression modelling suggested that cognitive-perceptual attributes were uniquely predicted by stress sensitivity in models that include resilience. In contrast, interpersonal attributes had a weaker relationship with stress sensitivity and were strongly predicted by poor resilience. In general, resilience did not moderate the relationship of stress sensitivity with schizophrenia liability. Unexpectedly, some specific attributes of resilience (personal strength, structured style) potentiated the relationship of stress sensitivity with schizophrenia liability. We conclude that the relationships of stress sensitivity, resilience, and coping with attributes of schizophrenia liability are not uniform and speculate that the pattern of associations may reflect the different influences of chronic stress exposures and neurocognitive functioning.

Comparisons of schizotypal traits across 12 countries: Results from the International Consortium for Schizotypy Research.

BACKGROUND: Schizotypal traits are expressions of underlying vulnerability to psychotic disorders which have a potential impact on mental health status, neurocognition, quality of life, and daily functioning. To date, little research has examined epidemiologic landscape of schizotypal traits at the cross-national level. Our aim was to study the expression of schizotypal traits by sex, age, and country in a combined sample gathered from 12 countries. METHODS: A total of 27,001 participants completed the Schizotypal Personality Questionnaire (SPQ). The mean age of participants was 22.12 (SD=6.28); 37.5% (n=10,126) were males. RESULTS: Schizotypal traits varied according to sex, age, and country. Females scored higher than males in the positive dimension, whereas males scored higher in the disorganization dimension. By age, a significant decrease in the positive schizotypal traits was observed. Epidemiological expression of schizotypal traits varied by country. Moreover, several interactions by sex, age, and country were found. CONCLUSIONS: This pattern is similar to those found in patients with psychosis and psychotic-like experiences. These findings provide new insights and the opportunity to explore the phenotypic expression of schizotypal traits at cross-national level.

Brief assessment of schizotypal traits: A multinational study.

The Schizotypal Personality Questionnaire-Brief (SPQ-B) was developed with the aim of examining variations in healthy trait schizotypy, as well as latent vulnerability to psychotic-spectrum disorders. No previous study has studied the cross-cultural validity of the SPQ-B in a large cross-national sample. The main goal of the present study was to analyze the reliability and the internal structure of SPQ-B scores in a multinational sample of 28,426 participants recruited from 14 countries. The mean age was 22.63years (SD=7.08; range 16-68years), 37.7% (n=10,711) were men. The omega coefficients were high, ranging from 0.86 to 0.92 for the total sample. Confirmatory factor analysis revealed that SPQ-B items were grouped either in a theoretical structure of three first-order factors (Cognitive-Perceptual, Interpersonal, and Disorganized) or in a bifactor model (three first-order factors plus a general factor of schizotypal personality). In addition, the results supported configural but not strong measurement invariance of SPQ-B scores across samples. These findings provide new information about the factor structure of schizotypal personality, and support the validity and utility of the SPQ-B, a brief and easy tool for assessing self-reported schizotypal traits, in cross-national research. Theoretical and clinical implications for diagnostic systems, psychosis models, and cross-national mental health strategies are derived from these results.