Ethnicity, class and schizotypy

Factor structure and measurement invariance of Schizotypal Personality Questionnaire-Brief Revised (Updated) in India

AIM

Schizotypal Personality Questionnaire-Brief Revised-Updated (SPQ-BRU) is an easy-to-conduct, theoretically consistent, and psychometrically better measure of schizotypal personality. However, its study is limited to developed countries. Thus, in the present study, we tested the factor structure and measurement invariance of SPQ-BRU in India.

METHODS

A sample of 734 college students was selected from two sites (n = 614 from Muzaffarnagar in western Uttar Pradesh and n = 120 from Guhana in Haryana). Confirmatory factor analysis was used to test the good fitness of the different models of SPQ-BRU and the measurement invariance across sex and region.

RESULTS

The first-order nine-factor model was a better-fit model (among a set of first-order and second-order models), whereas the second-order three-factor model was a more parsimonious good-fit model of SPQ-BRU. The nine-factor model was strongly invariant across sex and region. Women had higher social anxiety, ideas of reference, and lower constricted affect than men. Moreover, the Gohana sample was higher on several schizotypal personality facades than the Muzaffarnagar sample.

CONCLUSIONS

The present study supported the cross-cultural validity of schizotypal personality and partially established a reliable and valid SPQ-BRU-Hindi language version.

Examining delusional ideation: Relationships with race and socioeconomic status

Race and socioeconomic status (SES) are commonly cited as risk factors for psychosis and psychotic-like experiences (PLEs). However, few studies have investigated the relationships between race and SES with specific domains of PLEs. Specifically, little work has examined the relationships between race and SES with delusional ideation, severity (preoccupation, conviction, distress), and delusional themes. Using cross-sectional, general population data (N = 727) from the Nathan Kline Institute-Rockland (NKI-Rockland) database, we investigated racial differences in delusional ideation and severity between Black and White participants, including differences in delusional themes. Then, we investigated SES's relationship with delusional thinking and the interaction between race and SES on delusional thinking. Black American participants endorsed higher delusional ideation with stronger severity than White Americans. A significant interaction between race and delusional theme revealed that Black Americans endorse significantly more delusional ideation in themes of grandiosity, religiosity, and referential-guilt. Black Americans endorse greater delusional severity in grandiose and religious ideations. Black Americans endorse stronger preoccupation and conviction - but not distress-in their referential-guilt ideation. SES was not significantly associated with delusional thinking, nor did SES moderate the significant relationships between race and delusional ideation. These results illuminate the clear racial disparity that exist in delusional ideation within a general population, which did not extend to SES in this dataset. Future work should investigate deeper into the contributory factors to these racial disparities, particularly whether they are based in psychological and/or cultural differences or are the result of assessment/measurement bias.

Research on mental disorders and their care in immigrant populations: a review of publications from Germany, Italy and the UK

Objective

The review aims to identify the extent and nature of research on mental disorders and their care in immigrant populations in three major European countries with high levels of immigration, i.e. Germany, Italy, United Kingdom (UK).

Methods

Peer-reviewed publications on the subject from the three countries between 1996 and 2004 were analyzed. The research questions addressed, the methods used, and the results obtained were assessed.

Results

Thirteen papers reporting empirical studies were found from Germany, four from Italy and 95 from the UK. Studies addressed a range of research questions and most frequently assessed rates of service utilization in different immigrant groups. The most consistent finding is a higher rate of hospital admissions for Afro-Caribbean patients in the UK. Many studies had serious methodological shortcomings with low sample sizes and unspecified inclusion criteria.

Discussion

Despite large scale immigration in each of the three studied countries, the numbers of relevant research publications vary greatly with a relatively high level of empirical research in the UK. Possible reasons for this are a generally stronger culture of mental health service research and a higher number of researchers who are themselves from immigrant backgrounds in the UK.

Conclusion

Overall the evidence base to guide the development of mental health services for immigrant populations appears limited. Future research requires appropriate funding, should be of sufficient methodological quality and may benefit from collaboration across Europe.

Subclinical psychosis in adult migrants and ethnic minorities: systematic review and meta-analysis

BACKGROUND

It is well established that migration and ethnic minority status are risk factors for psychotic disorders. Recent studies have aimed to determine if they are also associated with subclinical psychosis (psychotic-like experiences and schizotypal traits).

AIMS

We aimed to determine to what extent migrant and ethnic minority groups are associated with higher risk of subclinical psychosis.

METHOD

We conducted a systematic review, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and examined findings by ethnicity, migrant status, outcomes of subclinical psychosis and host country. A meta-analysis was carried out with robust variance estimation where possible, to handle statistically dependent effect size estimates.

RESULTS

We included 28 studies (19 studies on psychotic-like experiences and 9 studies on schizotypal traits) and found that ethnicity, but not migrant status, was associated with current and lifetime psychotic-like experiences. In the narrative analysis, we observed the effect of psychosocial risk factors on this association: Black ethnicity groups showed consistent increased prevalence of current and lifetime psychotic-like experiences compared with the reference population across countries.

CONCLUSIONS

More generalisable and standardised cohort studies of psychotic-like experiences and schizotypal traits in relation to migration/ethnicity are necessary to examine the effects of exposures and outcomes in different contexts, and to understand the underlying mechanisms of the association between subclinical psychosis and migrant and ethnic minority status.

DECLARATION OF INTEREST

None.

Differential Item Functioning of the Full and Brief Wisconsin Schizotypy Scales in Asian, White, Hispanic, and Multiethnic Samples and Between Sexes

The Wisconsin Schizotypy Scales, including their brief versions, are among the most commonly used self-report measures of schizotypy. Although they have been used extensively in many ethnic groups, few studies have examined their differential item functioning (DIF) across groups. The current study included 1,056 Asian, 408 White, 476 Multiethnic, and 372 Hispanic undergraduates. Unidimensional models of the brief Magical Ideation Scale and Perceptual Aberration Scales fit the data well. For both scales, global tests of measurement invariance provided mixed evidence, but few of the items displayed DIF across ethnicities or between sexes within a multiple indicator multiple causes model. For the full versions of the scales and the brief Revised Social Anhedonia Scale, multiple indicator multiple causes models within an exploratory structural equation modeling framework found that few of the items had DIF. These findings suggest that some of the items may have different psychometric properties across groups, but most items do not.

Neuropsychological correlates of schizotypy: a systematic review and meta-analysis of cross-sectional studies

INTRODUCTION

Cognitive deficits can precede the onset of psychotic episodes and predict the onset of the illness in individuals with schizotypy traits. In some studies, high levels of schizotypy were associated with impairments in memory, attention, executive functions, and verbal fluency. This review provides a more comprehensive understanding of cognitive impairments related to schizoytpy.

METHODS

 A systematic review of "schizotypy and neuropsychological measures" was conducted, and it retrieved 67 studies. All papers with case-control design showing means and standard deviations from neuropsychological measures were included in a meta-analysis (n = 40). A comparison between our finding and another metaanalysis with patients with schizophrenia-spectrum disorders [Fatouros-Bergman, H., Cervenka, S., Flyckt, L., Edman, G., & Farde, L. (2014). Meta-analysis of cognitive performance in drugnaive patients with schizophrenia. Schizophrenia Research. doi: 10.1016/j.schres.2014.06.034 ] was performed to study the similarities on the MATRICS domains between the two disorders.

RESULTS

We found evidence of worse functioning of verbal and visual-spatial working memory, and of language in people with schizotypy or with schizotypal traits. Working memory deficit is present in both schizotypy and schizophrenia with larger effect sizes compared to other domains.

CONCLUSIONS

 Working memory deficit might be a cognitive marker of the risk of psychosis. Interventions targeting cognitive deficits early may be crucial to the prevention of psychosis.

Measurement Invariance of the Prodromal Questionnaire-Brief Among White, Asian, Hispanic, and Multiracial Populations

The Prodromal Questionnaire-Brief is a scale that is used to screen individuals for risk for the development of psychosis. It has promising psychometric properties in clinical and nonclinical populations, including undergraduates. However, the measurement invariance of the scale has not been examined in Asian, White, Hispanic, and Multiracial samples. A total of 2,767 undergraduates at two large public U.S. universities completed the Prodromal Questionnaire-Brief. The Total scores had configural and scalar invariance, while the Distress scores displayed configural, metric, and partial scalar invariance. Follow-up analyses revealed that three items were responsible for the lack of complete scalar invariance for the Distress scores. This suggests that the Total and Distress scores are measuring the same construct across groups and mean scores represent the same level of latent prodromal traits across groups. Mean comparisons for the Distress Scale across ethnicity should be interpreted with caution because it lacks complete scalar invariance. White and Hispanic participants had lower Total scores that Multiracial and Asian participants, and this pattern emerged for 13 items. For the distress items that were scalar invariant, the Asian group reported more distress than the White and Hispanic groups, while the Multiracial group reported more distress than the White group.

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.

Perceived discrimination and psychotic experiences across multiple ethnic groups in the United States

OBJECTIVE

The objective of this study was to examine the relationship between perceived discrimination and psychotic experiences (PE) using validated measures of discrimination and a racially/ethnically diverse population-level sample.

METHODS

Data were drawn from two population-level surveys (The National Latino and Asian American Survey and The National Survey of American Life), which were analyzed together using survey weights and stratification variables. The analytic sample (N=8990) consisted of Latino, Asian, African-American, and Afro-Caribbean adults living in the United States. Separate unadjusted and adjusted multivariable logistic regression models were used, first to examine the crude bivariate relationship between perceived discrimination and PE, and second to examine the relationship adjusting for demographic variables. Adjusted logistic regression models were also used to examine the relationships between perceived discrimination and specific sub-types of PE (auditory and visual hallucinatory experiences, and delusional ideation).

RESULTS

When compared to individuals who did not report any discrimination, those who reported the highest levels of discrimination were significantly more likely to report both 12-month PE (Adjusted OR=4.590, p<0.001) and lifetime PE (adjusted OR=4.270, p<0.001). This held true for visual hallucinatory experiences (adjusted OR=3.745, p<0.001), auditory hallucinatory experiences (adjusted OR=5.649, p<0.001), and delusional ideation (adjusted OR=7.208, p<0.001).

CONCLUSION

Perceived discrimination is associated with the increased probability of reporting psychotic experiences in a linear Fashion in the US general population.

Ethnicity, violent offending, and vulnerability to schizophrenia: a pilot study

Previous research has highlighted increased risk for schizophrenia in Afro-Caribbeans as well as over-representation in the prison population. This small-scale study examined the relationship between criminality, ethnicity, and psychosis-proneness in a male prison sample. Twenty British Caucasian and 20 Afro-Caribbean prisoners were divided into equal sub-groups of violent and non-violent offenders. Participants completed measures of schizotypy, delusional ideation, and hostility. Afro-Caribbean offenders scored more highly on negative schizotypy and delusional ideation than their Caucasian counterparts. Violent offenders scored more highly on the positive symptoms of schizotypy than non-violent prisoners. Both ethnicity and violent offending may be relevant factors when considering vulnerability to psychosis in the offending population.

The Community Assessment Psychic Experience (CAPE): evaluation study of the Italian version

Negli ultimi anni il modello categoriale della psicosi e della schizofrenia in particolare, è stato riconsiderato a favore di una visione dimensionale. Questa assume che I sintomi psicotici differiscono in modo quantitativo dalle normali esperienze psichiche distribuendosi lungo un continuum che va dalla popolazione clinica affetta da schizofrenia ad individui con disturbo di personalità, fino alla popolazione generale che può mostrare esperienze simil psicotiche (Hanssen et al., 2003; Johns & Phil, 2005). Tale continuità fenomenologica è suggerita da studi che mostrano che le dimensioni del fenotipo della psicosi subclinica sono molto simili a quelle identificate nei disturbi clinici (Van Os et al. 2000; Van Os & Tamminga, 2007; Rossler et al., 2007). Sono state infatti riportate dimensioni positive e negative sia in ambito clinico che subclinico, mentre più incerta appare la presenza della dimensione disorganizzazione (Vollema & Hoijtink, 2000; van Os et al., 2002). Vari studi hanno riportato che i fenotipi clinico e non clinico condividono fattori di rischio, meccanismi psicologici ed i pattern epidemiologici (Sharpley & Peters,1999; Johns & van Os, 2001; van Os et al., 2001), fornendo un'ulteriore prova che l'espressione clinica e subclinica delle psicosi fanno parte dello stesso continuum.

The epidemiology of schizophrenia: replacing dogma with knowledge

Major advances have been made in our understanding of the epidemiology of schizophrenia. We now know that the disorder is more common and severe in young men, and that the incidence varies geographically and temporally. Risk factors have been elucidated; biological risks include a family history of the disorder, advanced paternal age, obstetric complications, and abuse of drugs such as stimulants and cannabis. In addition, recent research has also identified social risk factors such as being born and brought up in a city, migration, and certain types of childhood adversity such as physical abuse and bullying, as well as social isolation and adverse events in adult life. Current research is focussing on the significance of minor psychotic symptoms in the general population, gene-environmental interaction, and how risk factors impact on pathogenesis; perhaps all risk factors ultimately impact on striatal dopamine as the final common pathway.

Migration, ethnicity, and psychosis: toward a sociodevelopmental model

There is consistent and strong evidence that the incidence of all psychoses is higher in many migrant and minority ethnic populations in a number of countries. The reasons for this are, however, unclear and a wide range of explanations have been proposed, from genetic to neurodevelopmental to psychosocial. In this article, we describe and evaluate the available evidence for and against each of these. What this shows is that: (1) there are few studies that have directly investigated specific risk factors in migrant and minority ethnic populations, with often only 1 or 2 studies of any relevance to specific explanations and (2) what limited research there has been tends to implicate a diverse range of social factors (including childhood separation from parents, discrimination and, at an area level, ethnic density) as being of potential importance. In an attempt to synthesize these disparate findings and provide a basis for future research, we go on to propose an integrated model--of a sociodevelopmental pathway to psychosis--to account for the reported high rates in migrant and minority ethnic populations. Aspects of this model will be directly tested in a new Europe-wide incidence and case-control study that we will conduct over the next 3 years, as part of the European Network of National Schizophrenia Networks studying Gene-Environment Interactions programme.

Evidence that self-reported psychotic experiences represent the transitory developmental expression of genetic liability to psychosis in the general population

It has been suggested that self-reported, common, non-clinical psychotic experiences may represent the transitory developmental expression of distributed genetic risk for psychosis. In a sample of female MZ (176 pairs) and DZ twins (113 pairs), cross-twin, cross-trait analyses were conducted to investigate the association between repeated continuous measures of self-reported psychotic experiences (PE-three measures over 18 months), assessed with the CAPE, in one twin and clinical interview categorical measures of psychotic symptoms (PS), assessed with SCID-I, in the other twin. The results showed that in MZ but not DZ pairs (interaction: chi(2) = 7.9, df = 1, P = 0.005), the cross-twin association between PE and PS was large and significant (standardized effect size: 0.26, 95% CI: 0.10-0.42) and of similar magnitude as the within-twin PE-PS association (standardized effect size: 0.28, 95% CI: 0.10-0.45), demonstrating both PE validity and genetic effects. In addition, the cross-twin association between PE and PS was significantly larger (interaction: chi(2) = 20.3, df = 1, P < 0.0001) for younger MZ twins (standardized effect size: 0.67, 95% CI: 0.44-0.90) than older MZ twins (standardized effect size: -0.05, 95% CI: -0.26 to 0.16), demonstrating developmental effects. This study indicates that self-reported psychotic experiences in the general population may represent the developmental expression of population genetic risk for psychosis.

Psychotic symptoms and general health in a socially disadvantaged migrant community in Bologna

BACKGROUND AND AIMS

Social exclusion and reduced access to community health services can lead to urgent health problems among immigrants; this may explain their increasing rate of admittance to psychiatric inpatient units. This cross-sectional study aims to evaluate the prevalence of psychotic symptoms among Romanian immigrants living in very poor conditions at an abandoned hotel in Bologna and to highlight the possible correlation with general health status, distress and socio-demographic characteristics.

METHODS

The Psychosis Screening Questionnaire (PSQ) and General Health Questionnaire-12 (GHQ-12) were administered to all immigrants residing at the hotel during two index days with the help of a cultural mediator. Socio-demographic, migration and health characteristics were also collected.

RESULTS

Sixty eight subjects were evaluated. More than 80% had left Romania for economic reasons. Of immigrants, 57% exceeded the four-point GHQ-12 threshold of potential mental disorder and 19% scored positively at the PSQ. Immigrants with positive PSQ showed higher mean GHQ-12 scores (5.9 +/- 3.5 vs. 3.8 +/- 2.75; p = 0.02). The development of post-migration health problems significantly predicts positive PSQ cases even after adjusting for age, sex and GHQ-12 dichotomized score (OR = 21.2, CI = 1.1-169.4).

CONCLUSION

This community of immigrants living in deprived conditions showed a high prevalence of distress and psychotic symptoms, related to health problems. Preventing excess of psychosis among immigrants and ethnic minorities in critical socio-economic conditions should mean, first and foremost, facilitating social integration and access to primary care.

Latent class analysis of delusion-proneness: exploring the latent structure of the Peters et al. delusions inventory

Latent class analysis (LCA) has emerged as the best suitable statistical tool to identify separate dimensions (latent classes) when analyzing dichotomous data; its objective is to categorize people into classes using the observed items and to identify those items that best distinguish between classes. LCA was applied to the Peters et al. delusions inventory, an inventory in a dichotomous format (Yes/No) aimed at investigating proneness to delusion in the general population. The study involved 82 patients diagnosed with a psychotic disorder and 210 well-matched healthy controls from the community. Four classes were identified in the sample: a normative one, and 3 classes traceable to the 3 major dimensions of psychosis, i.e., paranoia, grandiosity/hypomania, and the schizophrenia-like profile. The coherent multidimensional structure of the model emerging from LCA of Peters et al. delusions inventory suggests that single clusters of symptoms may be indicative of specific diagnostic categories within the spectrum of psychoses, allowing a more subtle determination of their boundaries and correlates.

Schizophrenia in black Caribbeans living in the UK: an exploration of underlying causes of the high incidence rate

The incidence of schizophrenia in black Caribbeans living in the UK is substantially higher than in the white British population. When first reported, these findings were assumed to be a first-generation migrant effect or merely the result of methodological artefacts associated with inconsistencies in the diagnosis of schizophrenia in black Caribbeans and doubts about population denominators. More recently, it has become clear that the incidence of schizophrenia, based on standardised diagnosis and sophisticated census methods, is higher still in second-generation black Caribbeans. The largest study to date has demonstrated a ninefold higher risk of schizophrenia in UK-resident black Caribbeans: findings that are of concern to black Caribbean communities, to their GPs, and to health service managers responsible for resource allocation. A literature search was carried in order to explore possible reasons for the reported excess incidence of schizophrenia in UK-resident black Caribbeans. Competing hypotheses are reviewed and the paper concludes with a summary of specific social and psychological risk factors of significance within the black Caribbean community. Awareness of the factors associated with the onset and presentation of schizophrenia in black Caribbeans may help early diagnosis and rapid access to appropriate treatment which, in turn, appear to be related to improved long-term outcomes.

Measuring psychosis proneness in a nonclinical Korean population: is the Peters et al Delusions Inventory useful for assessing high-risk individuals?

OBJECTIVES

We examined the psychometric properties of the Korean version of the Peters et al Delusions Inventory (PDI) 40 and investigated the distribution of delusional ideation in a nonclinical population. We also used the item response theory to evaluate the usefulness of the PDI in measuring the risk for psychosis.

METHODS

A total of 310 nonclinical individuals completed the Korean PDI-40, the Magical Ideation Scale (MIS), and the Schizotypal Personality Scale (STA). In addition, 60 psychotic inpatients with delusions completed the PDI-40. Among 310 individuals, 124 participated in a follow-up study 6 months after completing their original questionnaire.

RESULTS

The PDI-40 revealed a slightly skewed distribution, but the score range was similar to that of the British population. Scores were negatively correlated with age, but no sex differences were found. The Korean PDI-40 exhibited good internal consistency and test-retest reliability. The PDI was significantly correlated with the MIS and the STA. Ten components were extracted through a principal component analysis with varimax rotation. The test results using item response theory revealed 39 items as the items which individuals with very high level of psychosis proneness will answer as "yes." Moreover, all items yielded "above moderate" discrimination in terms of psychosis proneness.

CONCLUSIONS

We confirmed the reliability and validity of the Korean PDI-40. The usefulness of the PDI-40 in a nonclinical population was replicated in the Korean sample. The PDI-40 can be used as an informative device when investigating "psychosis proneness" in a group at high risk for psychosis.

Perceptions of disadvantage, ethnicity and psychosis

BACKGROUND

People from Black ethnic groups (African-Caribbean and Black African) are more prone to develop psychosis in Western countries. This excess might be explained by perceptions of disadvantage.

AIMS

To investigate whether the higher incidence of psychosis in Black people is mediated by perceptions of disadvantage.

METHOD

A population-based incidence and case-control study of first-episode psychosis (Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP)). A total of 482 participants answered questions about perceived disadvantage.

RESULTS

Black ethnic groups had a higher incidence of psychosis (OR= 4.7, 95% CI 3.1-7.2). After controlling for religious affiliation, social class and unemployment, the association of ethnicity with psychosis was attenuated (OR=3.0, 95% CI 1.6-5.4) by perceptions of disadvantage. Participants in the Black non-psychosis group often attributed their disadvantage to racism, whereas Black people in the psychosis group attributed it to their own situation.

CONCLUSIONS

Perceived disadvantage is partly associated with the excess of psychosis among Black people living in the UK. This may have implications for primary prevention.

Ethnicity as a variable in mental health research: a systematic review of articles published 1990-2004

The objective of the study was to investigate how the ethnic variable has been used in mental health research, in theory, in measurement and classification criteria. Journal articles published 1990-2004 that address original research on psychopathology, treatment and mental health services and with "ethnic" or "ethnicity" in their title or abstract were selected. The papers were examined for their theoretical definition of ethnicity, how the ethnic data were collected and the criteria used to identify ethnic groups. The use of comparison groups and country of the studies were recorded. A total of 421 papers were identified. An explicit theoretical definition was found in 33 (7.8%) papers. Data collection procedure was mentioned in 248 (58.9%) and 104 (24.7%) papers described how data was converted into ethnic groups. The operationalizations of ethnicity have remained almost unchanged during the 15-year review period. Generally, the ethnic variable was incompletely reported. Confusion regarding which individual or social characteristics ethnicity refers to makes the research findings of limited value in clinical settings, and may continue to create misunderstanding about the effect of ethnicity in clinical contexts.

The contribution of social factors to the development of schizophrenia: a review of recent findings

OBJECTIVE

To investigate recent evidence suggesting that social factors are causally related to the development of schizophrenia.

METHOD

I conducted a sytematic review of MEDLINE to identify possibly relevant studies. The search was limited to peer-reviewed studies and review articles appearing in English-language journals since 1996. Studies were included if they used standardized diagnostic criteria for schizophrenia or standardized assessment instruments for psychotic symptoms.

RESULTS

Studies of migrants to western Europe provide compelling support for the notion that social factors contribute to the development of schizophrenia. Findings such as excessively high risk for schizophrenia in second-generation immigrants are difficult to explain solely in terms of biological or genetic factors. A growing number of studies implicate childhood exposure to social adversity as a risk factor for schizophrenia, although few studies have used prospective designs. The increased incidence of schizophrenia risk associated with urban birth and (or) urban upbringing suggests possible social causation, but these findings are more ambiguous. Thus far, no studies have explored actual mechanisms by which exposure to social factors might generate psychotic symptoms, although animal experiments suggest that social defeat or social exclusion may cause dopamine dysregulation or sensitization.

CONCLUSIONS

The accumulating evidence suggesting a role for social factors in the development of schizophrenia arises primarily from studies of migrants conducted in Europe. The mechanisms by which social factors exert their influence remain unknown. Future investigations of social causation should clarify the temporal relation between exposure to social defeat and (or) social adversity and the development of psychotic symptoms.

Validity and reliability of the CAPE: a self-report instrument for the measurement of psychotic experiences in the general population

OBJECTIVE

General population longitudinal cohort studies have demonstrated the prognostic validity of self-reported psychotic experiences, but data on reliability and cross-validation with interview-based measures of these experiences are sparse. This study tested the reliability and validity of the Community Assessment of Psychic Experiences (CAPE42).

METHOD

At baseline, the CAPE42 was used to measure the subclinical psychosis phenotype in a general population sample (n = 765). At follow-up (mean interval: 7.7 months), the Structured Interview for Schizotypy, Revised (SIS-R), the Brief Psychiatric Rating Scale (BPRS), and the CAPE42 were administered (n = 510).

RESULTS

Baseline self-reported dimensions of psychosis were specifically and independently associated with their equivalent interview-based dimension at follow-up (standardized effect sizes of 0.4-0.5) and with their equivalent self-reported measure (standardized effect sizes of 0.6-0.8).

CONCLUSION

The results indicate that self-reported dimensions of psychotic experiences in general population samples appear to be stable, reliable and valid.

Over-representation of Maori New Zealanders among adolescents in a schizotypy taxon

BACKGROUND

Minority ethnic and migrant groups are often over-represented among those with schizophrenia.

OBJECTIVES

The aim of this study was to determine whether Maori, the aboriginal minority of New Zealand, are over-represented in a schizotypy taxon derived from a general population sample of adolescents.

METHOD

Secondary school students (n = 387) aged 13 to 17 years completed self-report measures of four schizotypy attributes, magical thinking, hallucinatory tendency, self-referential ideation, and perceptual aberration, and indicated ethnic descent and self-identified ethnic belonging.

RESULTS

Taxometric analyses (maximum covariance, maximum eigenvalue, latent modes) yielded consistent evidence of taxonicity of schizotypy. Participants who were of Maori descent were over-represented in the schizotypy group.

CONCLUSIONS

Ethnicity, or the stress and resilience factors for which ethnicity is a proxy measure, has a measurable impact on psychometric risk for schizophrenia.

Trajectories of psychosis: towards a new social biology of schizophrenia

Over the last 2 decades, discourse on the causes of schizophrenia was conducted almost entirely in terms of biological risk factors. This was probably the result of social trends in the research community, and in popular culture, as a wave of techno-optimism promised answers to big human questions in terms of small pixels and even smaller molecules. The human genome project inflated expectations further, and the pharmaceutical industry conspired with the desire of psychiatrists for scientific respectability. 'Social factors', whether at macro-societal or locality/family level, came to be seen as 'fall-out' from biological mechanisms, a kind of padding to our understanding of human disease. But changes are in the wind. New understandings of the influence of social factors on the long-term outcome trajectories of psychosis, their potential role in risks associated with migration, and recent findings from genetic high risk studies, are raising fresh questions about social factors and causation. This paper does not argue that the evidence (yet) is strong. But after 2 decades of often crudely articulated dualism, it is time once again for social experience to be integrated with more sophisticated theory development and hypothesis testing in the search for the causes of schizophrenia.

Early maternal stress and health behaviours and offspring expression of psychosis in adolescence

OBJECTIVE

It has been suggested that influences operating early in life may affect the risk of postpubertal psychosis outcomes. This hypothesis was tested using a broad outcome of psychotic symptoms expressed in adolescence (prevalence: 15.6%).

METHOD

Findings are based on a longitudinal, population-based cohort study of 963 adolescents aged 15-20 years and their parents in the area of Munich, Germany. Trained psychologists assessed adolescents with the Munich-Composite International Diagnostic Interview. Independently, direct diagnostic interviews were conducted with the parents.

RESULTS

A range of medical complications of pregnancy and delivery, including lower birth weight, were not associated with the psychosis outcome. However, a number of maternal health behaviours and experiences did show associations, independent of confounders.

CONCLUSION

Not maternally reported medical complications of pregnancy and delivery, but maternal prenatal health behaviours predicted expression of psychosis along a continuum in adolescence. This effect may either be direct or constitute a proxy for later postnatal maternal behaviours associated with psychosis risk in the offspring.

Psychiatric admissions for psychosis in Malmö during the NATO bombing of Kosovo

Little is known about the possible mechanisms contributing to increased risk for psychosis found among immigrants. We used the NATO bombing campaign of Kosovo as a naturalistic experiment to explore the role of potentially stressful aspects of minority group status. We examined all patient admissions to the psychiatric clinic in Malmö during the months of the NATO campaign in Kosovo in 1999 and during control months in 1997. Admission rates showed significantly differing trends over time, with an increasing proportion of immigrant patients with psychosis admitted during the NATO campaign months and a decreasing proportion of such patients admitted during control months. A significantly greater proportion of the immigrant patients admitted for psychosis during the NATO campaign months versus control months had been exposed to extreme duress before migration. Cumulative adversity, either solely or in combination with current stress, may possibly contribute to increased risk for psychosis among immigrants.

Ethnicity and four personality disorders

The current study examined the relationship between ethnicity and DSM-IV personality disorders. The distribution of four personality disorders--borderline (BPD), schizotypal (STPD), avoidant (AVPD), and obsessive-compulsive (OCPD)--along with their criteria sets, were compared across three ethnic groups (Caucasians, African Americans, and Hispanics) using both a clinician-administered diagnostic interview and a self-report instrument. Participants were 554 patients drawn from the Collaborative Longitudinal Personality Disorders Study (CLPS) who comprised these three ethnic groups and met personality disorder criteria based on reliably administered semistructured interviews. Chi-square analyses revealed disproportionately higher rates of BPD in Hispanic than in Caucasian and African American participants and higher rates of STPD among African Americans when compared to Caucasians. Self-report data reflected similar patterns. The findings suggest that in treatment-seeking samples, Caucasians, Hispanics, and African Americans may present with different patterns of personality pathology. The factors contributing to these differences warrant further investigation.

Discrimination and delusional ideation

BACKGROUND

In the UK and The Netherlands, people with high rates of psychosis are chronically exposed to discrimination.

AIMS

To test whether perceived discrimination is associated longitudinally with onset of psychosis.

METHOD

A 3-year prospective study of cohorts with no history of psychosis and differential rates of reported discrimination on the basis of age, gender, disability, appearance, skin colour or ethnicity and sexual orientation was conducted in the Dutch general population (n=4076). The main outcome was onset of psychotic symptoms (delusions and hallucinations).

RESULTS

The rate of delusional ideation was 0.5% (n=19) in those who did not report discrimination, 0.9% (n=4) in those who reported discrimination in one domain, and 2.7% (n=3) in those who reported discrimination in more than one domain (exact P=0.027). This association remained after adjustment for possible confounders. No association was found between baseline discrimination and onset of hallucinatory experiences.

CONCLUSIONS

Perceived discrimination may induce delusional ideation and thus contribute to the high observed rates of psychotic disorder in exposed minority populations.

Understanding the excess of psychosis among the African-Caribbean population in England. Review of current hypotheses

BACKGROUND

Increased rates of schizophrenia continue to be reported among the African-Caribbean population in England.

AIMS

To evaluate the competing biological, psychological and social explanations that have been proposed.

METHOD

Literature review.

RESULTS

The African-Caribbean population in England is at increased risk of both schizophrenia and mania; the higher rates remain when operational diagnostic criteria are used. The excess of the two psychotic disorders are probably linked: African-Caribbean patients with schizophrenia show more affective symptoms, and a more relapsing course with greater social disruption but fewer chronic negative symptoms, than White patients. No simple hypothesis explains these findings.

CONCLUSIONS

More complex hypotheses are needed. One such links cultural variation in symptom reporting, the use of phenomenological constructs by psychiatrists and social disadvantage.