Migration, ethnicity and psychoses: evidence, models and future directions

Language proficiency and mental disorders among migrants: A systematic review

BACKGROUND

In this review, we aimed to evaluate the association between language proficiency (LP) and the prevalence and severity of mental disorders in migrants. Secondarily, we aimed to consider whether sociodemographic and migration-related factors may affect the correlation between LP and mental disorders.

METHODS

MEDLINE, PsycArticles, EMBASE, and PsycInfo were systematically searched in April 2020 to identify original studies reporting prevalence of psychiatric symptoms or disorders among migrants and taking into account linguistic factors.

RESULTS

The search of electronic databases initially yielded 1,944 citations. Of the 197 full texts assessed for eligibility, 41 studies were selected for inclusion in the systematic review. Thirty-five of the papers included reported a significant negative association between low LP and prevalence and/or severity of psychiatric symptoms or disorders, whereas only two records found the opposite relationship and four papers reported no association between them. Inadequate LP was consistently associated with several mental disorders in migrants, including psychotic, mood, anxiety, and post-traumatic stress disorders. Notably, all the four longitudinal studies that met inclusion criteria for this review reported a positive effect of LP acquisition over time on prevalence or symptom severity of mental disorders.

CONCLUSIONS

Even though larger prospective studies are needed to better evaluate the relationship between LP and psychiatric disorders among migrants, we believe that the present findings could be inspiring for authorities to provide support and courses to improve migrants' language proficiency upon arrival.

From Womb to Neighborhood: A Racial Analysis of Social Determinants of Psychosis in the United States

The authors examine U.S.-based evidence that connects characteristics of the social environment with outcomes across the psychosis continuum, from psychotic experiences to schizophrenia. The notion that inequitable social and economic systems of society significantly influence psychosis risk through proxies, such as racial minority and immigrant statuses, has been studied more extensively in European countries. While there are existing international reviews of social determinants of psychosis, none to the authors' knowledge focus on factors in the U.S. context specifically-an omission that leaves domestic treatment development and prevention efforts incomplete and underinformed. In this review, the authors first describe how a legacy of structural racism in the United States has shaped the social gradient, highlighting consequential racial inequities in environmental conditions. The authors offer a hypothesized model linking structural racism with psychosis risk through interwoven intermediary factors based on existing theoretical models and a review of the literature. Neighborhood factors, cumulative trauma and stress, and prenatal and perinatal complications were three key areas selected for review because they reflect social and environmental conditions that may affect psychosis risk through a common pathway shaped by structural racism. The authors describe evidence showing that Black and Latino people in the United States suffer disproportionately from risk factors within these three key areas, in large part as a result of racial discrimination and social disadvantage. This broad focus on individual and community factors is intended to provide a consolidated space to review this growing body of research and to guide continued inquiries into social determinants of psychosis in U.S. contexts.

Characteristics associated with the risk of psychosis among immigrants and their descendants in France

OBJECTIVE

To explore the sociodemographic characteristics that might explain the increased incidence of psychosis among immigrants and their descendants in France.

METHODS

Data were collected for all subjects with first contact for psychosis aged between 18 and 64 years, in two catchment areas in the Paris region. Incidence rates (IR) and incidence rate ratios (IRR) were adjusted for gender and age.

RESULTS

During 805,396 persons-year at risk, we identified 321 cases of first-episode psychosis, of which 129 were immigrants and 78 descendants of immigrants. We found that the geographic origin was associated with the risk of psychosis although generation has little impact. Sub-Saharan African immigrants and their descendants showed the highest risk (IRR = 3.1 and IRR = 2.9, respectively). We observed that living in deprived areas increased the incidence of psychosis (IRR = 1.3, 95CI%: 1.0-1.6), particularly among immigrants (IRR = 1.6; 95% CI: 1.1-2.5). Finally, our study showed that subjects having unstable housing (a proxy for "hard to count population") could inflate the incidence rates among immigrants.

CONCLUSION

The current study shows that the increased risk of psychosis in groups with an immigration background in France is associated with their origin and highlights the importance of socioeconomic factors in modulating this risk.

Risk of psychotic disorders in migrants to Australia

BACKGROUND

Certain migrant groups are at an increased risk of psychotic disorders compared to the native-born population; however, research to date has mainly been conducted in Europe. Less is known about whether migrants to other countries, with different histories and patterns of migration, such as Australia, are at an increased risk for developing a psychotic disorder. We tested this for first-generation migrants in Melbourne, Victoria.

METHODS

This study included all young people aged 15-24 years, residing in a geographically-defined catchment area of north western Melbourne who presented with a first episode of psychosis (FEP) to the Early Psychosis Prevention and Intervention Centre (EPPIC) between 1 January 2011 and 31 December 2016. Data pertaining to the at-risk population were obtained from the Australian 2011 Census and incidence rate ratios were calculated and adjusted for age, sex and social deprivation.

RESULTS

In total, 1220 young people presented with an FEP during the 6-year study period, of whom 24.5% were first-generation migrants. We found an increased risk for developing psychotic disorder in migrants from the following regions: Central and West Africa (adjusted incidence rate ratio [aIRR] = 3.53, 95% CI 1.58-7.92), Southern and Eastern Africa (aIRR = 3.06, 95% CI 1.99-4.70) and North Africa (aIRR = 5.03, 95% CI 3.26-7.76). Migrants from maritime South East Asia (aIRR = 0.39, 95% CI 0.23-0.65), China (aIRR = 0.25, 95% CI 0.13-0.48) and Southern Asia (aIRR = 0.44, 95% CI 0.26-0.76) had a decreased risk for developing a psychotic disorder.

CONCLUSION

This clear health inequality needs to be addressed by sufficient funding and accessible mental health services for more vulnerable groups. Further research is needed to determine why migrants have an increased risk for developing psychotic disorders.

First-episode Psychosis and Migration in Italy: Results from a Study in the Italian Mental Health Services (Pep-Ita Study)

Background: Migrants present high rates of psychosis. A better understanding of this phenomenon is needed. Methods: We conducted a multicentre First-Episode Psychosis (FEP) prospective study over two years (January 2012–December 2013) to evaluate first-generation migrants presenting with FEP at the participating Community Mental Health Centers (CMHCs). Results: 109 FEP migrants were identified. Almost half of them were highly educated, employed and in a stable affective relationship. The average age was 32.8 (± 9.8) years, and the average length of stay in Italy was 8.6 (± 8.8) years. About 2/3 of patients were referred to CMHCs following Emergency Department access or psychiatric admission. Conclusions: Our finding of a “high functioning portrait” of FEP migrants allow us to hypothesize that a high burden of negative psychosocial factors is likely to be needed for the FEP onset. Furtherly, mental health services should implement more appropriate resources and organizational methods to respond to migrants’ health needs.

Perceived major experiences of discrimination, ethnic group, and risk of psychosis in a six-country case-control study

BACKGROUND

Perceived discrimination is associated with worse mental health. Few studies have assessed whether perceived discrimination (i) is associated with the risk of psychotic disorders and (ii) contributes to an increased risk among minority ethnic groups relative to the ethnic majority.

METHODS

We used data from the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions Work Package 2, a population-based case-control study of incident psychotic disorders in 17 catchment sites across six countries. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) for the associations between perceived discrimination and psychosis using mixed-effects logistic regression models. We used stratified and mediation analyses to explore differences for minority ethnic groups.

RESULTS

Reporting any perceived experience of major discrimination (e.g. unfair treatment by police, not getting hired) was higher in cases than controls (41.8% v. 34.2%). Pervasive experiences of discrimination (≥3 types) were also higher in cases than controls (11.3% v. 5.5%). In fully adjusted models, the odds of psychosis were 1.20 (95% CI 0.91-1.59) for any discrimination and 1.79 (95% CI 1.19-1.59) for pervasive discrimination compared with no discrimination. In stratified analyses, the magnitude of association for pervasive experiences of discrimination appeared stronger for minority ethnic groups (OR = 1.73, 95% CI 1.12-2.68) than the ethnic majority (OR = 1.42, 95% CI 0.65-3.10). In exploratory mediation analysis, pervasive discrimination minimally explained excess risk among minority ethnic groups (5.1%).

CONCLUSIONS

Pervasive experiences of discrimination are associated with slightly increased odds of psychotic disorders and may minimally help explain excess risk for minority ethnic groups.

The clinical characterization of the patient with primary psychosis aimed at personalization of management

The current management of patients with primary psychosis worldwide is often remarkably stereotyped. In almost all cases an antipsychotic medica-tion is prescribed, with second-generation antipsychotics usually preferred to first-generation ones. Cognitive behavioral therapy is rarely used in the vast majority of countries, although there is evidence to support its efficacy. Psychosocial interventions are often provided, especially in chronic cases, but those applied are frequently not validated by research. Evidence-based family interventions and supported employment programs are seldom implemented in ordinary practice. Although the notion that patients with primary psychosis are at increased risk for cardiovascular diseases and diabetes mellitus is widely shared, it is not frequent that appropriate measures be implemented to address this problem. The view that the management of the patient with primary psychosis should be personalized is endorsed by the vast majority of clinicians, but this personalization is lacking or inadequate in most clinical contexts. Although many mental health services would declare themselves "recovery-oriented", it is not common that a focus on empowerment, identity, meaning and resilience is ensured in ordinary practice. The present paper aims to address this situation. It describes systematically the salient domains that should be considered in the characterization of the individual patient with primary psychosis aimed at personalization of management. These include positive and negative symptom dimensions, other psychopathological components, onset and course, neurocognition and social cognition, neurodevelopmental indicators; social functioning, quality of life and unmet needs; clinical staging, antecedent and concomitant psychiatric conditions, physical comorbidities, family history, history of obstetric complications, early and recent environmental exposures, protective factors and resilience, and internalized stigma. For each domain, simple assessment instruments are identified that could be considered for use in clinical practice and included in standardized decision tools. A management of primary psychosis is encouraged which takes into account all the available treatment modalities whose efficacy is supported by research evidence, selects and modulates them in the individual patient on the basis of the clinical characterization, addresses the patient's needs in terms of employment, housing, self-care, social relationships and education, and offers a focus on identity, meaning and resilience.

Third external replication of an individualised transdiagnostic prediction model for the automatic detection of individuals at risk of psychosis using electronic health records

BACKGROUND

Primary indicated prevention is a key target for reducing the incidence and burden of schizophrenia and related psychotic disorders. An individualised, clinically-based transdiagnostic model for the detection of individuals at risk of psychosis has been developed and validated in two large, urban healthcare providers. We tested its external validity in a geographically and demographically different non-urban population.

METHOD

Retrospective EHR cohort study. All individuals accessing secondary healthcare provided by Oxford Health NHS Foundation Trust between 1st January 2011 and 30th November 2019 and receiving a primary index diagnosis of a non-psychotic or non-organic mental disorder were considered eligible. The previously developed model was applied to this database and its external prognostic accuracy was measured with Harrell's C.

FINDINGS

The study included n = 33,710 eligible individuals, with an average age of 27.7 years (SD = 19.8), mostly white (92.0%) and female (57.3%). The mean follow-up was 1863.9 days (SD = 948.9), with 868 transitions to psychosis and a cumulative incidence of psychosis at 6 years of 2.9% (95%CI: 2.7-3.1). Compared to the urban development database, Oxford Health was characterised by a relevant case mix, lower incidence of psychosis, different distribution of baseline predictors, higher proportion of white females, and a lack of specialised clinical services for at risk individuals. Despite these differences the model retained an adequate prognostic performance (Harrell's C = 0.79, 95%CI: 0.78-0.81), with no major miscalibration.

INTERPRETATION

The transdiagnostic, individualised, clinically-based risk calculator is transportable outside urban healthcare providers. Further research should test transportability of this risk prediction model in an international setting.

Social Defeat, Psychotic Symptoms, and Crime in Young Caribbean Immigrants to Rotterdam

Background: The negative experience of being excluded from the majority group (social defeat) may be associated with psychosis in immigrants. The social defeat hypothesis is supported by the high frequency of perceived discrimination and acculturation problems in psychotic immigrants. In addition, social defeat may lead to crime through social problems such as unemployment, school dropout, a broken family structure, or psychotic symptoms. Methods: We assessed the association between social defeat and acculturation on the one hand and broadly defined psychotic symptoms and crime on the other in Caribbean immigrants to Rotterdam who are aged 18-24 years. The municipality of Rotterdam provided data about Caribbean immigrants to Rotterdam. Acculturation, social defeat (perceived discrimination, sense of control, and evaluation of self and others), psychotic symptoms, and crime were assessed using online questionnaires. Results: Social defeat was associated with psychotic symptoms in women (β = 0.614, p < 0.001). This relation applied particularly to the negative self-perception domain of social defeat. Acculturation was associated with neither social defeat nor psychotic symptoms or crime and did not mediate the association between social defeat and psychosis. Conclusion: The social defeat hypothesis of psychosis may be gender-specific valid but does not extend to crime.

Understanding the excess psychosis risk in ethnic minorities: the impact of structure and identity

PURPOSE

Psychotic disorders, which are associated with substantially increased morbidity and mortality, are up to five times more common in some ethnic minority groups compared with the white majority in Western countries. This long-standing and well-replicated public mental health disparity has hitherto largely eluded adequate explanation. We argue that this might have arisen in part due to the lack of attention given to theoretical work characterising the complex and multidimensional social nature of ethnicity by those epidemiological investigations that have dominated the literature.

METHODS

To bridge this gap, we draw on theoretical and empirical literature from across the social sciences considering the ontological significance of ethnicity (as biology, migration, racialised structures and identity) and its relationships with psychotic disorders to illuminate probable drivers of excess psychosis risk.

RESULTS

The largest gains in our theoretical understanding of excess psychosis risk among ethnic minority groups are to be made by considering ethnicity in relation to disempowerment resulting from structural and identity-based exclusion. The former is readily studied through the social gradient in health: socioeconomic disadvantage clusters in some ethnic minorities and increases the risk of poor health outcomes, including psychosis. Furthermore, limitations on identity acquisition and expression imposed by the ethnic majority can further contribute to alienate ethnic minorities and increase psychosocial disempowerment (a lack of control over one's life).

CONCLUSION

We theorise that structural and identity-based exclusion act as the primary drivers shaping variation in rates of psychotic disorder by ethnic minority status.

Demographic and clinical characteristics of foreign nationals accessing psychiatric services in Japan: a multicentre study in a metropolitan area

BACKGROUND

International immigration to Japan, where homogeneous ethnicity is a population characteristic, has been growing. Although immigration is recognised as a risk factor for multiple mental-health related issues, there are few regional reports on foreign nationals accessing the psychiatric services in Japan. We aimed to reveal their current status and provide information to develop an optimal service system.

METHODS

A multicentre retrospective document review research was conducted. The subjects were foreign nationals who resided in Japan and presented at the psychiatry departments in three core regional hospitals in the Keihin region, which faces Tokyo Bay and is well known to include the largest traditional industrial zone in Japan, over a period of 3 years. We investigated the patients' demographic and clinical information including country/region of origin, spoken language, use of a medical interpreter, pathway to hospitals and outcome.

RESULTS

The percentage of foreign patients among all patients (1.4%) was quite low. Their age distribution (45.8 years on average) was dissociated from the age distribution of foreign nationals who resided in Japan. Regarding the country/region of origin, China (35.1%) was the most common country, followed by the Philippines, Korea and Brazil. Several subjects (22.9%) could not speak Japanese; therefore, interpretation was required by family members/friends (17.1%) or a professional interpreter (5.4%). Neurotic and stress-related disorders were the most common diagnosis (24.4%). The proportion of psychoactive substance use was higher than that for Japanese national data as immigrants are known to be at risk for it.

CONCLUSIONS

The results suggest that foreign nationals who reside in Japan are less likely to contact appropriate services for mental illness, especially young people at relatively high risk of mental illness do not access services. Furthermore, lack of medical interpreters may impede the mental health conditions of foreign nationals. The development of a community-based integrated care system accessible to foreign nationals seems to be indispensable.

Exploring indigenous ethnic inequities in first episode psychosis in New Zealand - A national cohort study

INTRODUCTION

First episode psychosis (FEP) disproportionately affects rangatahi (young) Māori, the Indigenous people of New Zealand, but little is known about factors contributing to this inequity. This study describes a cohort of rangatahi Māori and young non-Māori with FEP, and explores ethnic differences in incidence rates, and the contribution of deprivation, urbanicity and substance use.

METHODS

Māori and young non-Māori, aged 13-25 at the time of the first recorded psychosis-related diagnoses, were identified from within Statistics NZ's Integrated Data Infrastructure (IDI), between 2009 and 2012. To estimate age-standardised FEP incidence rates, the population-at-risk was estimated using IDI-based usual resident population estimates for 2009-2012, stratified by ethnicity and single year of age. Poisson regression models were used to estimate ethnic differences in FEP incidence adjusted for age, gender, deprivation, and urban-rural area classification.

RESULTS

A total of 2412 young people with FEP (40% Māori, 60% non-Māori) were identified. Māori were younger, and more likely to live in deprived and rural communities and be diagnosed with schizophrenia. Substance induced psychosis was uncommon. The unadjusted age-standardised FEP incidence rate ratio was 2.48 (95% CI: 2.29-2.69) for rangatahi Māori compared with young non-Māori. While adjusting for age, sex, deprivation and urban rural area classification reduced ethnic differences in incidence, rangatahi Māori were still more than twice as likely to have been diagnosed with FEP compared to young non-Māori.

CONCLUSIONS

This study confirms previous findings of elevated rates of psychosis among rangatahi Māori. The difference in rates between Māori and non-Māori were attenuated but remained after adjustment for deprivation and urbanicity.

Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): I. Psychosis superspectrum

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a scientific effort to address shortcomings of traditional mental disorder diagnoses, which suffer from arbitrary boundaries between psychopathology and normality, frequent disorder co-occurrence, heterogeneity within disorders, and diagnostic instability. This paper synthesizes evidence on the validity and utility of the thought disorder and detachment spectra of HiTOP. These spectra are composed of symptoms and maladaptive traits currently subsumed within schizophrenia, other psychotic disorders, and schizotypal, paranoid and schizoid personality disorders. Thought disorder ranges from normal reality testing, to maladaptive trait psychoticism, to hallucinations and delusions. Detachment ranges from introversion, to maladaptive detachment, to blunted affect and avolition. Extensive evidence supports the validity of thought disorder and detachment spectra, as each spectrum reflects common genetics, environmental risk factors, childhood antecedents, cognitive abnormalities, neural alterations, biomarkers, and treatment response. Some of these characteristics are specific to one spectrum and others are shared, suggesting the existence of an overarching psychosis superspectrum. Further research is needed to extend this model, such as clarifying whether mania and dissociation belong to thought disorder, and explicating processes that drive development of the spectra and their subdimensions. Compared to traditional diagnoses, the thought disorder and detachment spectra demonstrated substantially improved utility: greater reliability, larger explanatory and predictive power, and higher acceptability to clinicians. Validated measures are available to implement the system in practice. The more informative, reliable and valid characterization of psychosis-related psychopathology offered by HiTOP can make diagnosis more useful for research and clinical care.

Perceived ethnic discrimination as a risk factor for psychotic symptoms: a systematic review and meta-analysis

BACKGROUND

Previous studies have shown an elevated risk of psychotic symptoms (PS) and experiences (PEs) among ethnic minority groups, with significant variation between groups. This pattern may be partially attributable to the unfavorable socio-environmental conditions that surround ethnic minority groups. Perceived ethnic discrimination (PED) in particular has been a salient putative risk factor to explain the increased risk.

METHODS

We conducted a systematic literature review and meta-analysis to assess the impact of PED on reporting PS/PEs in ethnic minorities. This review abides by the guidelines set forth by Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The included studies were obtained from the databases: Medline, PsycINFO, and Web Of Science. Sub-group analyses were performed assessing the effect of PED in different subtypes of PS, the influence of ethnicity and moderating/mediating factors.

RESULTS

Seventeen studies met the inclusion criteria, and nine were used to conduct the meta-analysis. We found a positive association between PED and the occurrence of PS/PEs among ethnic minorities. The combined odds ratio were 1.77 (95% CI 1.26-2.49) for PS and 1.94 (95% CI 1.42-2.67) for PEs. We found that the association was similar across ethnic groups and did not depend on the ethnic origin of individuals. Weak evidence supported the buffering effects of ethnic identity, collective self-esteem and social support; and no evidence supported the moderating effect of ethnic density. Sensitivity to race-based rejection significantly but only slightly mediated the association.

CONCLUSION

These findings suggest that PED is involved in the increased risk of PS/PEs in ethnic minority populations.

Association of neighbourhood migrant density and risk of non-affective psychosis: a national, longitudinal cohort study

BACKGROUND

Elevated risk of psychotic disorders in migrant groups is a public mental health priority. We investigated whether living in areas of high own-region migrant density was associated with reduced risk of psychotic disorders among migrants and their children, and whether generation status, probable visible minority status, or region-of-origin affected this relationship.

METHODS

We used the Swedish registers to identify migrants and their children born between Jan 1, 1982, and Dec 31, 1996, and living in Sweden on or after their 15th birthday. We tracked all included participants from age 15 years or date of migration until emigration, death, or study end (Dec 31, 2016). The outcome was an ICD-10 diagnosis of non-affective psychosis (F20-29). We calculated own-region and generation-specific own-region density within the 9208 small areas for market statistics neighbourhoods in Sweden, and estimated the relationship between density and diagnosis of non-affective psychotic disorders using multilevel Cox proportional hazards models, adjusting for individual confounders (generation status, age, sex, calendar year, lone dwelling, and time since migration [migrants only]), family confounders (family income, family unemployment, and social welfare), and neighbourhood confounders (deprivation index, population density, and proportion of lone dwellings), and using the Akaike information criterion (AIC) to compare model fit.

FINDINGS

Of 468 223 individuals included in the final cohort, 4582 (1·0%) had non-affective psychotic disorder. Lower own-region migrant density was associated with increased risk of psychotic disorders among migrants (hazard ratio [HR] 1·05, 95% CI 1·02-1·07 per 5% decrease) and children of migrants (1·03, 1·01-1·06), after adjustment. These effects were stronger for probable visible minority migrants (1·07, 1·04-1·11), including migrants from Asia (1·42, 1·15-1·76) and sub-Saharan Africa (1·28, 1·15-1·44), but not migrants from probable non-visible minority backgrounds (0·99, 0·94-1·04). Among migrants, adding generation status to the measure of own-region density provided a better fit to the data than overall own-region migrant density (AIC 36 103 vs 36 106, respectively), with a 5% decrease in generation-specific migrant density corresponding to a HR of 1·07 (1·04-1·11).

INTERPRETATION

Migrant density was associated with non-affective psychosis risk in migrants and their children. Stronger protective effects of migrant density were found for probable visible minority migrants and migrants from Asia and sub-Saharan Africa. For migrants, this risk intersected with generation status. Together, these results suggest that this health inequality is socially constructed.

FUNDING

Wellcome Trust, Royal Society, Mental Health Research UK, University College London, National Institute for Health Research, Swedish Research Council, and FORTE.

Dopamine and glutamate in schizophrenia: biology, symptoms and treatment

Glutamate and dopamine systems play distinct roles in terms of neuronal signalling, yet both have been proposed to contribute significantly to the pathophysiology of schizophrenia. In this paper we assess research that has implicated both systems in the aetiology of this disorder. We examine evidence from post-mortem, preclinical, pharmacological and in vivo neuroimaging studies. Pharmacological and preclinical studies implicate both systems, and in vivo imaging of the dopamine system has consistently identified elevated striatal dopamine synthesis and release capacity in schizophrenia. Imaging of the glutamate system and other aspects of research on the dopamine system have produced less consistent findings, potentially due to methodological limitations and the heterogeneity of the disorder. Converging evidence indicates that genetic and environmental risk factors for schizophrenia underlie disruption of glutamatergic and dopaminergic function. However, while genetic influences may directly underlie glutamatergic dysfunction, few genetic risk variants directly implicate the dopamine system, indicating that aberrant dopamine signalling is likely to be predominantly due to other factors. We discuss the neural circuits through which the two systems interact, and how their disruption may cause psychotic symptoms. We also discuss mechanisms through which existing treatments operate, and how recent research has highlighted opportunities for the development of novel pharmacological therapies. Finally, we consider outstanding questions for the field, including what remains unknown regarding the nature of glutamate and dopamine function in schizophrenia, and what needs to be achieved to make progress in developing new treatments.