Morbid risk of schizophrenia in first-degree relatives of white and African-Caribbean patients with psychosis

Stress, Environment and Early Psychosis

Existing literature provides extended evidence of the close relationship between stress dysregulation, environmental insults, and psychosis onset. Early stress can sensitize genetically vulnerable individuals to future stress, modifying their risk for developing psychotic phenomena. Neurobiological substrate of the aberrant stress response to hypothalamic-pituitary-adrenal axis dysregulation, disrupted inflammation processes, oxidative stress increase, gut dysbiosis, and altered brain signaling, provides mechanistic links between environmental risk factors and the development of psychotic symptoms. Early-life and later-life exposures may act directly, accumulatively, and repeatedly during critical neurodevelopmental time windows. Environmental hazards, such as pre- and perinatal complications, traumatic experiences, psychosocial stressors, and cannabis use might negatively intervene with brain developmental trajectories and disturb the balance of important stress systems, which act together with recent life events to push the individual over the threshold for the manifestation of psychosis. The current review presents the dynamic and complex relationship between stress, environment, and psychosis onset, attempting to provide an insight into potentially modifiable factors, enhancing resilience and possibly influencing individual psychosis liability.

Effects of country of origin and wave of immigration on prevalence of schizophrenia among first and second-generation immigrants: A 30-year retrospective study

OBJECTIVES

To compare the rates of schizophrenia among 1st and 2nd generation immigrants from two distinct backgrounds and across sequential periods of immigration.

METHODS

A 30-years retrospective cohort study (187,184 individuals) of 1st and 2nd generation East-African immigrants (EAIs) and former Soviet-Union immigrants (FSUIs) who migrated to Israel between 1980 and 2012. EAIs were further divided according to waves of immigration. Period prevalence was calculated between the years 2002-2012. Multivariate logistic regression models were used to examine the association between immigration-related factors and prevalence of schizophrenia (Native-Born Israelis serving as reference group).

RESULTS

The prevalence of schizophrenia in 1st generation EAIs and FSUIs was 1.8% and 1.2%, respectively, compared to 1.0% among NBIs (p<0.001). The prevalence of schizophrenia among 2nd generation EAIs and FSUIs was 1.3% and 0.8%, respectively, compared to 0.6% among NBIs (p<0.001). Adjusted odds ratios for developing schizophrenia compared to NBIs were 1.6 (95%CI:1.4-1.8) and 2.1 (95%CI:1.6-2.7), among 1st and 2nd generation EAIs and 1.1 (95%CI:0.9-1.2) and 1.3 (95%CI:1.0-1.8) among 1st and 2nd generation FSUIs respectively. Among EAIs, we observed the highest rate of schizophrenia in the pioneer wave of immigrants with gradual decline across subsequent waves: 2.4%, 1.9% and 1.0% for the 1st, 2nd and 3rd waves of immigration, respectively (p<0.001).

CONCLUSIONS

The increased risk for developing schizophrenia among 2nd generation immigrants and among pioneer groups of immigrants emphasizes the importance of persistent investment in acculturation. Further studies elucidating the impact of country of origin and ethnic density on the risk for developing schizophrenia are warranted.

Change in incidence rates for psychosis in different ethnic groups in south London: findings from the Clinical Record Interactive Search-First Episode Psychosis (CRIS-FEP) study

BACKGROUND

A higher incidence of psychotic disorders has been consistently reported among black and other minority ethnic groups, particularly in northern Europe. It is unclear whether these rates have changed over time.

METHODS

We identified all individuals with a first episode psychosis who presented to adult mental health services between 1 May 2010 and 30 April 2012 and who were resident in London boroughs of Lambeth and Southwark. We estimated age-and-gender standardised incidence rates overall and by ethnic group, then compared our findings to those reported in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses (ÆSOP) study that we carried out in the same catchment area around 10 years earlier.

RESULTS

From 9109 clinical records we identified 558 patients with first episode psychosis. Compared with ÆSOP, the overall incidence rates of psychotic disorder in southeast London have increased from 49.4 (95% confidence interval (CI) 43.6-55.3) to 63.1 (95% CI 57.3-69.0) per 100 000 person-years at risk. However, the overall incidence rate ratios (IRR) were reduced in some ethnic groups: for example, IRR (95% CI) for the black Caribbean group reduced from 6.7 (5.4-8.3) to 2.8 (2.1-3.6) and the 'mixed' group from 2.7 (1.8-4.2) to 1.4 (0.9-2.1). In the black African group, there was a negligible difference from 4.1 (3.2-5.3) to 3.5 (2.8-4.5).

CONCLUSIONS

We found that incidence rates of psychosis have increased over time, and the IRR varied by the ethnic group. Future studies are needed to investigate more changes over time and determinants of change.

Impact of Season of Birth on Psychiatric Disorder Susceptibility and Drug Abuse Incidence in a Population from the Köppen Tropical Savanna Region of Brazil

BACKGROUND

Despite much evidence that season of birth (SOB) my influence the vulnerability to psychiatric disorders, divergence has been reported, in particular between populations born in the northern and southern hemispheres. We analyzed the potential modified risk by SOB to psychiatric disorder or drug addiction comorbidity in a population born in the Triângulo Mineiro region, a southern hemisphere Köppen tropical savanna region in Brazil.

METHOD

We accessed the records of 98,457 of patients and healthy controls of the National Datacenter of Medical Promptuary to evaluate the influence of SOB as a modifying factor on the occurrence of mental disorders and drug abuse conditions among individuals born from the year 2000 to 2016.

RESULTS

The data revealed significant modification of the relative incidence of major depressive disorder (MDD) (F11, 72 = 2.898; p = 0.003; eta-squared, ES = 0.313; ⍺ = 0.97), anxiety-related disorder (ARD) (F11, 81 =2.389; p = 0.013; ES = 0.241; ⍺ = 0.932), and schizophrenia (SZ) (F11, 83 = 2.764; p = 0.005; ES = 0.303; α = 0.963), while there was no increase in the number of healthy controls born in any month of the year (F11, 71 = 1.469; p = 0.163). Post hoc analyses indicated a significant higher vulnerability to MDD or ARD if the patient was born in August, or October to December, respectively. A relative increase in the incidence of SZ was also observed in patients born from August to October, compared to patients born from November to January.

CONCLUSIONS

SOB may influence the risk for psychiatric disorders in the TMR population. Regional particularities associated with the climatic regime may account for the apparent divergence between studies.

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.

Age at migration and the risk of psychotic disorders: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of the existing evidence on the association between age at migration and the risk of psychotic disorders.

METHODS

Observational studies were eligible for inclusion if they presented data on the association between age at migration and the risk of psychotic disorders among first-generation migrant groups. We used two random effects meta-analyses to pool effect estimates for each stratum of age at migration relative to (i) a native-born reference category and (ii) the youngest age stratum (0 to 2 years).

RESULTS

Ten studies met inclusion criteria, and five were included in the meta-analysis. The risk of psychotic disorder among people who migrate prior to age 18 is nearly twice as high as the native-born population, with no evidence of effect modification by age strata. People who migrate during early adulthood (19 to 29 years) have a similar risk of psychotic disorder as the native-born population (IRR = 0.93, 95% CI = 0.60, 1.44) and a lower risk relative to those who migrate during infancy (0 to 2 years) (IRR = 0.58, 95% CI = 0.33, 1.04).

CONCLUSIONS

Migrant status is one of few well-established risk factors for psychotic disorder, yet we have limited understanding of the underlying etiology. The findings of this review advance our understanding of this association and identify high-risk groups to target for intervention.

Risk of schizophrenia in relatives of individuals affected by schizophrenia: A meta-analysis

A meta-analysis was conducted to estimate schizophrenia incidence in first-degree relatives (FDRs) of probands diagnosed with schizophrenia. The aim was to inform future schizophrenia research and improve accuracy of risk communication to patients. Schizophrenia risk in FDRs with 1 or 2 probands with schizophrenia was investigated by conducting a systematic review of cohort and case-control studies with the following criteria: published between 1977 and 2018; reported odds ratios (OR), relative risk (RR) or sufficient raw data to calculate OR or RR; used appropriate diagnostic criteria; and reported systematic proband recruitment and ascertainment of relatives. Studies were obtained via EMBASE and MEDLINE electronic database searches. From an initial 5755 articles, 19 met the inclusion criteria. Mean effect sizes across studies were estimated using random effects methods. Estimates for schizophrenia risk were OR = 7.69 (95% CI 5.11-11.56) for FDRs of one proband with schizophrenia compared to healthy control probands, increasing to OR = 11.11 (95% CI = 1.45-85.02) for FDRs with two probands with schizophrenia. These findings support the existing literature suggesting significant genetic liability for schizophrenia. The results can be used to educate individuals with a family history of schizophrenia about their risk.

Psychology across cultures: Challenges and opportunities

Large variations of inequalities in rates of mental health disorders and access to mental health care exist within and between countries. Globally, disparities range from countries where there is little provision to those where, despite the availability of evidence-based mental health care, service access and outcomes are mediated by social factors such as socio-economic status, race/ethnicity, and culture. This is salient because increasingly diverse populations are inevitably created with globalization. We posit that in multicultural contexts, effective therapeutic engagement requires therapists who are competent and confident to work with diversity and difference, utilizing insights into their own as well as their clients' internal and external worlds. Although there are many reasons why psychotherapies can be insensitive and harmful, for example, the inherent power imbalance in therapeutic relationships, a lack of awareness of cultural and ethnic variation and needs are among them. Acquisition of 'cultural competence' and increasing availability of culturally-adapted interventions should, in theory, enable practitioners to work with a range of individuals with whom they might have little in common. However, whilst cultural adaptation appears promising, there are concerns regarding its viability as a strategy for tackling disparities in access to psychological care. Evidence for cultural competency is patchy at best. We show how and why delivering effective psychotherapy in the twenty-first century requires a paradigm shift from current approaches to truly integrated models, developed in collaboration with recipients of care. Coproducing interventions, training, and means of evaluating them with clients necessitates taking into consideration social contexts, alternative conceptualizations of mental health and disorders and difficulties, and what constitutes appropriate helpful interventions for psychological distress. PRACTITIONER POINTS: Upskilling therapists to work with diversity and difference is essential for effective delivery of psychological treatments. Increasing the availability of culturally-adapted interventions together with therapists who are sufficiently competent and confident to deliver them should enable practitioners to work with a range of individuals with whom they might have little in common. Coproducing culturally appropriate means of responding to mental health difficulties, staff training and development, and service evaluation methods with clients necessitates taking into consideration social contexts, alternative explanatory models of mental health and 'illness', and what constitutes helpful interventions for psychological distress.

Social Environment and Epigenetics

Our social environment, from the microscopic to the macro-social, affects us for the entirety of our lives. One integral line of research to examine how interpersonal and societal environments can get "under the skin" is through the lens of epigenetics. Epigenetic mechanisms are adaptations made to our genome in response to our environment which include tags placed on and removed from the DNA itself to how our DNA is packaged, affecting how our genes are read, transcribed, and interact. These tags are affected by social environments and can persist over time; this may aid us in responding to experiences and exposures, both the enriched and the disadvantageous. From memory formation to immune function, the experience-dependent plasticity of epigenetic modifications to micro- and macro-social environments may contribute to the process of learning from comfort, pain, and stress to better survive in whatever circumstances life has in store.

Amygdala reactivity in ethnic minorities and its relationship to the social environment: an fMRI study

BACKGROUND

Ethnic minority individuals have an increased risk of developing a psychotic disorder, particularly if they live in areas of ethnic segregation, or low own group ethnic density. The neurobiological mechanisms underlying this ethnic minority associated risk are unknown. We used functional MRI to investigate neural responses to faces of different ethnicity, in individuals of black ethnicity, and a control group of white British ethnicity individuals.

METHODS

In total 20 individuals of black ethnicity, and 22 individuals of white British ethnicity underwent a 3T MRI scan while viewing faces of black and white ethnicity. Own group ethnic density was calculated from the 2011 census. Neighbourhood segregation was quantified using the Index of Dissimilarity method.

RESULTS

At the within-group level, both groups showed greater right amygdala activation to outgroup faces. Between groups, the black ethnicity group showed greater right amygdala activation to white faces, compared to the white ethnicity group. Within the black ethnicity group, individuals living in areas of lower own group ethnic density showed greater right amygdala reactivity to white faces (r = -0.61, p = 0.01).

CONCLUSIONS

This is the first time an increased amygdala response to white faces has been demonstrated in individuals of black ethnicity. In the black ethnicity group, correlations were observed between amygdala response and neighbourhood variables associated with increased psychosis risk. These results may have relevance for our understanding of the increased rates of paranoia and psychotic disorders in ethnic minority individuals.

African–Caribbeans and schizophrenia: contributing factors

The epidemiology and management of schizophrenia have been well studied over the past few decades. In the UK, key findings that have emerged time and again are the excess prevalence and incidence rates of schizophrenia among people of African–Caribbean origin. The reasons for this excess and the implications of this finding are many. The findings may reflect a true excess or a methodological artefact related to errors in the estimation of numerator and denominator data. The findings have been increasingly accepted as better designed studies have emerged, but these still do not fully address concerns about the nature of schizophrenia in other cultural groups and in societies in which industrialisation and economic productivity of the individual are not considered to be as crucial for an individual's sense of belonging in a community.

The Role of Genes, Stress, and Dopamine in the Development of Schizophrenia

The dopamine hypothesis is the longest standing pathoetiologic theory of schizophrenia. Because it was initially based on indirect evidence and findings in patients with established schizophrenia, it was unclear what role dopamine played in the onset of the disorder. However, recent studies in people at risk of schizophrenia have found elevated striatal dopamine synthesis capacity and increased dopamine release to stress. Furthermore, striatal dopamine changes have been linked to altered cortical function during cognitive tasks, in line with preclinical evidence that a circuit involving cortical projections to the striatum and midbrain may underlie the striatal dopamine changes. Other studies have shown that a number of environmental risk factors for schizophrenia, such as social isolation and childhood trauma, also affect presynaptic dopaminergic function. Advances in preclinical work and genetics have begun to unravel the molecular architecture linking dopamine, psychosis, and psychosocial stress. Included among the many genes associated with risk of schizophrenia are the gene encoding the dopamine D2 receptor and those involved in the upstream regulation of dopaminergic synthesis, through glutamatergic and gamma-aminobutyric acidergic pathways. A number of these pathways are also linked to the stress response. We review these new lines of evidence and present a model of how genes and environmental factors may sensitize the dopamine system so that it is vulnerable to acute stress, leading to progressive dysregulation and the onset of psychosis. Finally, we consider the implications for rational drug development, in particular regionally selective dopaminergic modulation, and the potential of genetic factors to stratify patients.

Early-life experiences and the development of adult diseases with a focus on mental illness: The Human Birth Theory

In mammals, early adverse experiences, including mother-pup interactions, shape the response of an individual to chronic stress or to stress-related diseases during adult life. This has led to the elaboration of the theory of the developmental origins of health and disease, in particular adult diseases such as cardiovascular and metabolic disorders. In addition, in humans, as stated by Massimo Fagioli's Human Birth Theory, birth is healthy and equal for all individuals, so that mental illness develop exclusively in the postnatal period because of the quality of the relationship in the first year of life. Thus, this review focuses on the importance of programming during the early developmental period on the manifestation of adult diseases in both animal models and humans. Considering the obvious differences between animals and humans we cannot systematically move from animal models to humans. Consequently, in the first part of this review, we will discuss how animal models can be used to dissect the influence of adverse events occurring during the prenatal and postnatal periods on the developmental trajectories of the offspring, and in the second part, we will discuss the role of postnatal critical periods on the development of mental diseases in humans. Epigenetic mechanisms that cause reversible modifications in gene expression, driving the development of a pathological phenotype in response to a negative early postnatal environment, may lie at the core of this programming, thereby providing potential new therapeutic targets. The concept of the Human Birth Theory leads to a comprehension of the mental illness as a pathology of the human relationship immediately after birth and during the first year of life.

Schizophrenia

Schizophrenia is a chronic psychiatric disorder with a heterogeneous genetic and neurobiological background that influences early brain development, and is expressed as a combination of psychotic symptoms - such as hallucinations, delusions and disorganization - and motivational and cognitive dysfunctions. The mean lifetime prevalence of the disorder is just below 1%, but large regional differences in prevalence rates are evident owing to disparities in urbanicity and patterns of immigration. Although gross brain pathology is not a characteristic of schizophrenia, the disorder involves subtle pathological changes in specific neural cell populations and in cell-cell communication. Schizophrenia, as a cognitive and behavioural disorder, is ultimately about how the brain processes information. Indeed, neuroimaging studies have shown that information processing is functionally abnormal in patients with first-episode and chronic schizophrenia. Although pharmacological treatments for schizophrenia can relieve psychotic symptoms, such drugs generally do not lead to substantial improvements in social, cognitive and occupational functioning. Psychosocial interventions such as cognitive-behavioural therapy, cognitive remediation and supported education and employment have added treatment value, but are inconsistently applied. Given that schizophrenia starts many years before a diagnosis is typically made, the identification of individuals at risk and those in the early phases of the disorder, and the exploration of preventive approaches are crucial.

Current research on transcultural psychiatry in the Anglophone Caribbean: epistemological, public policy, and epidemiological challenges

In this article, we review recent research on mental health in the Caribbean. Three major themes emerge: (a) the effects of colonialism on the Caribbean psyche; (b) decolonization of psychiatric public policy, including innovative treatment approaches, deinstitutionalization, and community and policy responses to mental health issues; and (c) the nature and epidemiology of psychiatric pathology among contemporary Caribbean people, with particular focus on migration, genetic versus social causation of psychosis and personality disorders, and mechanisms of resilience and social capital. Caribbean transcultural psychiatry illustrates the principles of equipoise unique to developing countries that protect the wellness and continued survival of postcolonial Caribbean people.

Cultural aspects of schizophrenia

Over the past 50 years, schizophrenia as a disorder has been widely studied across cultures throughout the world. There are differences not only in the symptoms and presentation but also in outcome and prognosis. Various authors have tried to explore and explain such variation but the reasons for this are not always clear. In this paper, we review some of the cultural aspects of schizophrenia.

A plausible model of schizophrenia must incorporate psychological and social, as well as neuro developmental, risk factors

Subtle alterations in brain development caused by genes or early environmental hazards, such as obstetric complications, play a role in projecting some individuals on a trajectory toward schizophrenia. High-risk and cohort studies demonstrate that children destined to develop schizophrenia tend to have delayed milestones and subtle neuromotor and cognitive impairments (particularly in coordination and language). These neurocognitive problems lead to difficulties in interpersonal relations, and their progressive alienation makes these at-risk children more likely to harbor odd or paranoid ideas. This cascade of increasingly deviant development may then be compounded by brain maturational changes during adolescence with a resultant lability of the dopaminergic response to stress. As a result, the individual is more susceptible to the effects of the abuse of dopamine-releasing drugs, and to other risk factors such as migration or stressful life events; social isolation may be a common pathway underlying several of the social risk factors.

Schizophrenia, social class and immigrant status: the epidemiological evidence

Background — By the mid-1960s, the importance of socio-economic status for schizophrenia had been demonstrated in terms of differences between social-class groups in prevalence and incidence rates, illness course and outcome, and treatment experience. In the causation – selection debate, however, opinion had swung in favour of the selection hypothesis. Aims — To reassess evidence on the social-class distribution of schizophrenia in Britain, and to compare this body of research with population-based studies of schizophrenia risk in socially disadvantaged ethnic minorities. Method — Systematic review of medical and psychological data-bases. Results — Epidemiological research, while confirming the importance of premorbid social decline, has also provided support for the environmental ‘breeder’ hypothesis. High psychosis rates have been confirmed in ethnic minori-ties; in particular among Afro-Caribbean and other Black immigrants whose low social status cannot be accounted for by selective downward social drift or segregation. Conclusions — There are striking parallels, both in the epidemiology of schizophrenia and in social characteristics, between the lower-class indigenous groups highlighted by earlier psychiatric surveys and African-Caribbean populations in Britain's inner cities today. These similarities underline the need for a broader perspective in the search for environmental risk factors.

Declaration of Interest: none.

Canada: psychosis in the immigrant Caribbean population

BACKGROUND

Many reports from European countries suggest that acute episodes of psychosis are more frequent among immigrants from the Caribbean than among their non-immigrant peers.

AIM

The aim of this selective review is to examine how the social correlates of migration to Canada interact with biological mechanisms to contribute to psychosis in the Caribbean population.

METHOD

PubMed and JSTOR social science databases (between 1966 and 2010) were searched using the following search terms: psychiatric genetics; dopamine pathways; Caribbean family structure and child rearing; cannabis and psychosis; obstetric complications and schizophrenia; social defeat; social capital; racial discrimination; urbanicity; immigration; assimilation; and immigration. This was followed by the cross-checking of references pertinent to Canada.

RESULTS

There was no information about the prevalence of psychosis in Afro-Caribbean immigrant groups to Canada. There was a suggestion that the form the acute episode takes may differ, depending perhaps on the island of origin.

CONCLUSION

Ethnicity and migration influence susceptibility and response to psychotic illness in a number of distinct and interacting ways depending both on the host country and the country of origin. Understanding the pathways can help to protect the health of immigrants.

WPA guidance on mental health and mental health care in migrants

The purpose of this guidance is to review currently available evidence on mental health problems in migrants and to present advice to clinicians and policy makers on how to provide migrants with appropriate and accessible mental health services. The three phases of the process of migration and the relevant implications for mental health are outlined, as well as the specific problems of groups such as women, children and adolescents, the elderly, refugees and asylum seekers, and lesbian, gay, bisexual and transgender individuals. The concepts of cultural bereavement, cultural identity and cultural congruity are discussed. The epidemiology of mental disorders in migrants is described. A series of recommendations to policy makers, service providers and clinicians aimed to improve mental health care in migrants are provided, covering the special needs of migrants concerning pharmacotherapies and psychotherapies.

The environment and schizophrenia

Psychotic syndromes can be understood as disorders of adaptation to social context. Although heritability is often emphasized, onset is associated with environmental factors such as early life adversity, growing up in an urban environment, minority group position and cannabis use, suggesting that exposure may have an impact on the developing 'social' brain during sensitive periods. Therefore heritability, as an index of genetic influence, may be of limited explanatory power unless viewed in the context of interaction with social effects. Longitudinal research is needed to uncover gene-environment interplay that determines how expression of vulnerability in the general population may give rise to more severe psychopathology.

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.

The culture and identity schedule a measure of cultural affiliation: acculturation, marginalization and schizophrenia

BACKGROUND

Previous epidemiological studies have shown a high incidence of schizophrenia in African-Caribbeans in the UK, but not in Asians.

AIMS

We investigated the hypothesis that cultural adherence might protect the Asians against the stress of living in a majority white culture.

METHODS

The Culture and Identity Schedule (CANDID) was given to patients with a diagnosis of schizophrenia making their first contact with psychiatric services, and to a matched group of controls randomly selected from the general population.

RESULTS

While the Asian patients displayed no drift away from the traditional values as espoused by their controls, the African-Caribbean patients were less traditional than their controls.

CONCLUSIONS

The fact that a movement away from their traditional culture distinguishes African-Caribbean patients with a severe psychiatric illness, schizophrenia, from their mentally healthy controls strongly favours marginalization over biculturalism as an interpretation of this shift.

Ethnic diversity and pathways to care for a first episode of psychosis in Ontario

OBJECTIVE

To examine ethnic variations in the pathways to care for persons accessing early intervention (EI) services in Ontario.

METHOD

The pathways to care and the duration of untreated psychosis were assessed for first-episode psychosis patients who entered specialized EI services in Ontario. The sample was assigned to the following ethnic classifications: the White (Caucasian), Black (African descent), and Asian (ancestry from the continent) groups, plus all the "other ethnicities" group.

RESULTS

There were 200 participants: 78% were male; 61% from the White, 15% Black, 13% Asian, and 11% were from the other ethnicities group. At the first point of contact, more participants used nonmedical contacts (12%), such as clergy and naturopathic healers, than psychologists (8%) or psychiatrists (7%). There were no ethnic differences for duration of untreated psychosis (median 22 weeks) or for initiation of help seeking by family/friends (53%), police (15%), or self (33%). After adjusting for relevant clinical and demographic factors, the Asian and other ethnicities groups were 4 and 3 times (respectively) more likely than the White or Black groups (P = .017) to use emergency room services as the first point of contact in the pathways to care. Participants from the Asian group experienced less involuntary hospitalizations (P = .023) than all the other groups. Yet overall, there were many more similarities than significant differences in the pathways to care.

CONCLUSION

EI services should monitor the pathways to care for young people of diverse ethnic backgrounds to address any disparities in accessing care.

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.

Relation of schizophrenia prevalence to latitude, climate, fish consumption, infant mortality, and skin color: a role for prenatal vitamin d deficiency and infections?

Previous surveys found a large (>10-fold) variation in schizophrenia prevalence at different geographic sites and a tendency for prevalence to increase with latitude. We conducted meta-analyses of prevalence studies to investigate whether these findings pointed to underlying etiologic factors in schizophrenia or were the result of methodological artifacts or the confounding of sites' latitude with level of healthcare at those sites. We found that these patterns were still present after controlling for an index of healthcare--infant mortality--and focusing on 49 studies that used similar diagnostic and ascertainment methods. The tendencies for schizophrenia prevalence to increase with both latitude and colder climate were still large and significant and present on several continents. The increase in prevalence with latitude was greater for groups with low fish consumption, darker skin, and higher infant mortality--consistent with a role of prenatal vitamin D deficiency in schizophrenia. Previous research indicates that poor prenatal healthcare and nutrition increase risk for schizophrenia within the same region. These adverse conditions are more prevalent in developing countries concentrated near the equator, but schizophrenia prevalence is lowest at sites near the equator. This suggests that schizophrenia-producing environmental factors associated with higher latitude may be so powerful they overwhelm protective effects of better healthcare in industrialized countries. The observed patterns of correlations of risk factors with prevalence are consistent with an etiologic role for prenatal vitamin D deficiency and exposure to certain infectious diseases. Research to elucidate environmental factors that underlie variations in schizophrenia prevalence deserves high priority.

The other side of the healthy immigrant paradox: Chinese sojourners in Ireland and Britain who return to China due to personal and familial health crises

Based on participant observation and interviews conducted between 2003 and 2006, this paper examines the experiences of three young adult Chinese sojourners in Ireland and the United Kingdom who return to the People's Republic of China for permanent residence because of personal or familial health crises. Their experiences illustrate the plight of failed sojourners who are part of the little-studied other side of the "healthy immigrant paradox." The experiences of the sojourners in this case study illustrate factors that tend to prevent less healthy or resourceful sojourner families from even entering the immigrant category, which has been shown to be paradoxically healthier than nonimmigrant native categories in epidemiological studies. This paper's approach demonstrates how ethnography can contribute to the study of public health by shedding light on the experiences of marginal individuals who fall between the cracks of epidemiological studies.

Gene-environment interactions in schizophrenia: review of epidemiological findings and future directions

Concern is building about high rates of schizophrenia in large cities, and among immigrants, cannabis users, and traumatized individuals, some of which likely reflects the causal influence of environmental exposures. This, in combination with very slow progress in the area of molecular genetics, has generated interest in more complicated models of schizophrenia etiology that explicitly posit gene-environment interactions (EU-GEI. European Network of Schizophrenia Networks for the Study of Gene Environment Interactions. Schizophrenia aetiology: do gene-environment interactions hold the key? [published online ahead of print April 25, 2008] Schizophr Res; S0920-9964(08) 00170-9). Although findings of epidemiological gene-environment interaction (G x E) studies are suggestive of widespread gene-environment interactions in the etiology of schizophrenia, numerous challenges remain. For example, attempts to identify gene-environment interactions cannot be equated with molecular genetic studies with a few putative environmental variables "thrown in": G x E is a multidisciplinary exercise involving epidemiology, psychology, psychiatry, neuroscience, neuroimaging, pharmacology, biostatistics, and genetics. Epidemiological G x E studies using indirect measures of genetic risk in genetically sensitive designs have the advantage that they are able to model the net, albeit nonspecific, genetic load. In studies using direct molecular measures of genetic variation, a hypothesis-driven approach postulating synergistic effects between genes and environment impacting on a final common pathway, such as "sensitization" of mesolimbic dopamine neurotransmission, while simplistic, may provide initial focus and protection against the numerous false-positive and false-negative results that these investigations engender. Experimental ecogenetic approaches with randomized assignment may help to overcome some of the limitations of observational studies and allow for the additional elucidation of underlying mechanisms using a combination of functional enviromics and functional genomics.

Psychosis risk for parents and siblings of Dutch and Moroccan-Dutch patients with non-affective psychotic disorder

BACKGROUND

Studies in the UK compared psychosis risks for first-degree relatives of White and African-Caribbean patients and found "normal" risks for the parents of Caribbean patients, but very high risks for siblings of second-generation Caribbean patients.

AIM

To compare the risk of non-affective psychotic disorder (NAPD) for the parents and siblings of Moroccan-Dutch patients to that for the parents and siblings of Dutch patients. The "Moroccan-Dutch" are Dutch residents of Moroccan origin (first or second generation).

METHOD

Informants related to 29 Moroccan-Dutch and 63 Dutch patients were interviewed about the presence of psychiatric disorders in first-degree relatives (N=508), by means of the Family Interview for Genetic Studies.

RESULTS

The risks for NAPD in both parent groups were similar (age and sex-adjusted odds ratio 1.0; 95% CI: 0.3-3.8). However, among the siblings, the risk for NAPD was significantly higher for the Moroccan-Dutch than for the Dutch (sex-adjusted hazard ratio 4.5; 95% Confidence Interval: 1.5-14.0). This was due to a large number of cases among the brothers of the Moroccan-Dutch patients (N=14), not among their sisters (N=1). Owing to small numbers separate hazard ratios for the first and the second generation were not calculated.

CONCLUSION

These preliminary results suggest that environmental factors in the Netherlands have a great impact on the psychosis risk for male immigrants from Morocco.

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.

Biological, life course, and cross-cultural studies all point toward the value of dimensional and developmental ratings in the classification of psychosis

The diagnostic criteria for schizophrenia in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) are based on the premise that it is a discrete illness entity, in particular, distinct from the affective psychoses. This assumption has persisted for more than a century, even though patients with a diagnosis of schizophrenia show a wide diversity of symptoms and outcomes, and no biological or psychological feature has been found to be pathognomonic of the disorder. However, there has been sustained, and indeed growing, criticism of the concept. For example, writing about the diagnosis of schizophrenia more than a decade ago,2 one of Britain's most sophisticated nosological experts, Ian Brockington, enjoined "It is important to loosen the grip which the concept of 'schizophrenia' has on the minds of psychiatrists. Schizophrenia is an idea whose very essence is equivocal, a nosological category without natural boundaries, a barren hypothesis. Such a blurred concept is 'not a valid object of scientific enquiry'."3 Should Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition(DSM-V), persist with the neo-Kraepelinian concept of schizophrenia with all its defects, or should it deconstruct psychosis into its component dimensions? In this article, we will address the question by considering 2 main themes, firstly, the role of culture and ethnicity in the diagnosis of psychosis, and secondly, a life course approach to understanding psychosis. We will then discuss whether more progress would be achieved in DSM-V by abandoning the familiar categorical system and instead moving to a dimensional system which rates both developmental impairment and symptom factor scores. However, we will begin by briefly reviewing the recent history of the classification of the psychoses.

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.

The social causes of psychosis in North American psychiatry: a review of a disappearing literature

OBJECTIVE

To review the North American literature with respect to the role of social factors in the etiology of psychosis, including schizophrenia.

METHOD

Relevant publications were identified through a search of MEDLINE from 1966 to 2006. Identified studies and articles had to originate in Canada or the United States to be included in the review. Articles written prior to 1966 were identified by cross-referencing bibliographies and reference lists. Articles were considered relevant if they discussed ethnoracial or other social factors as being causal or contributing to the development of psychosis or schizophrenia.

RESULTS

The relation between the etiology of psychosis and such social factors as poverty, migration, and racial discrimination has been neglected in the North American psychiatric literature for the last 40 years. In Canada and the United States, there is a dearth of research on these issues: the study of social causes of psychosis has been replaced by a focus on the clinical encounter, in which clinician bias is presumed to be responsible for widespread misdiagnosis of psychosis in minority (mainly African-American) populations. The reasons for neglecting social causes of psychosis in the North American psychiatric literature are obscure but may have to do with the rise of genetic-biological paradigms in recent decades.

CONCLUSIONS

The neglect of social causes of psychosis in the North American psychiatric literature has been coincident with an increase in scholarly concern among European clinicians and researchers. Careful reading of the European literature may reveal helpful avenues for future investigation in the North American context. In addition, drawing on social science literature and methods may help to clarify mechanisms underlying poverty, migration, and racial discrimination that contribute to psychosis in vulnerable individuals and groups.

Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both?

European researchers have observed that schizophrenia is 3 times more frequent in immigrants than in native-born subjects. This increased risk is even higher in dark-skinned immigrants, and the second generation is more affected than the first one. Immigrant status is an important environmental risk factor not only for schizophrenia but also for other psychoses. The explanations proposed to date have been mainly related to epidemiological biases and psychological reasons, such as racism or social defeat, but no biological hypotheses have been tested so far. This article proposes two biological hypotheses related to changes in sun exposure, changes in diet, and stress associated with immigration, which would explain the increased risk for psychosis associated with immigrant status. (1) Vitamin D insufficiency has been proposed as a risk factor for schizophrenia. The main source of vitamin D is through photosynthesis by sun exposure, and dark skins need more sun exposure to maintain adequate blood levels. Vitamin D insufficiency in adulthood could explain why dark-skinned immigrants develop psychosis when moving to high latitude countries, and its insufficiency during pregnancy could explain why the observed risk is higher in the second generation. (2) The second hypothesis is that of epigenetics, with psychosis resulting from modifications in gene expression caused by changes in diet and/or stress related to immigration. The role of homocysteine and the vitamin B-complex, especially folic acid, in these changes in DNA transcription would vary according to the polymorphism of the methylenetetrahydrofolate reductase gene. The vitamin D insufficiency and epigenetics hypotheses are consistent with yet unexplained findings well known in the epidemiology of schizophrenia, such as the increased risk in the urban environment, the excess of winter births, the excess of schizophrenia births after maternal famine, and the shorter interbirth period before a schizophrenia birth. In order to test these hypotheses, epidemiological studies of psychosis and immigration should include objective measures of skin color, which is predicted to be a more important risk factor than ethnicity. They should measure vitamin D, homocysteine and vitamin B-complex status and assess the polymorphisms of the vitamin D receptors and the methylenetetrahydrofolate reductase gene. If confirmed, these hypotheses would lead to effective and inexpensive preventive measures which would markedly decrease the rates of psychosis and schizophrenia, as well as the burden and stigma of these diseases, and greatly improve the mental health of immigrants.

Migration and mental health: Japanese Brazilians in Japan and in Brazil

OBJECTIVE: Brazil is the country with the largest community of Japanese descendants in the world, from a migration movement that started in 1908. However, more recently (1988), a movement in the opposite direction began. Many of these descendants went to Japan for work purposes and suffered mental distress. Some of them sought treatment in Japan, while others returned to Brazil to seek treatment. The aim of the present study was to compare the sociodemographic profile and diagnoses of Japanese Brazilian psychiatric outpatients in Japan (remaining group) and in Brazil (returning group). METHOD: All consecutive Japanese Brazilian outpatients who received care from the psychiatric units in Japan and Brazil from April 1997 to April 2000 were compared. The diagnoses were based on ICD-10 and were made by psychiatrists. Sociodemographic data and diagnoses in Brazil and Japan were compared by means of the Chi-Squared Test. RESULTS: The individuals who returned to Brazil were mostly male and unmarried, had lived alone in Japan, had stayed there for short periods and were classified in the schizophrenia group. The individuals who remained in Japan were mostly female and married, were living with family or friends, had stayed there for long periods and were classified in the anxiety group. Logistic regression showed that the most significant factors associated with the returning group were that they had lived alone and stayed for short periods (OR = 0.93 and 40.21, respectively). CONCLUSION: We conclude that living with a family and having a network of friends is very important for mental health in the context evaluated.

The incidence of schizophrenia in European immigrants to Canada

OBJECTIVE

The risk for schizophrenia in immigrants to Europe is approximately three times that of native-born populations. Discrimination and marginalization may influence the risk for schizophrenia within migrant populations. The primary objective of the present study was to determine whether the risk associated with migration was also evident 100 years ago. A second objective was to determine whether changing social stresses are associated with changes to the incidence of schizophrenia.

METHOD

During the first two decades of the twentieth century, the Provincial Mental Hospital was the sole provider of psychiatric services in British Columbia, Canada. Detailed clinical records have been preserved for 99.5% of 2477 patients who had a psychiatric admission between 1902 and 1913. Diagnoses were made after a detailed file review and 807 patients met DSM-IV criteria for first-episode schizophrenia, schizophreniform disorder, schizoaffective disorder, or psychosis not otherwise specified. Diagnoses had high inter-rater reliability. The incidence of schizophrenia in migrants from Britain or Continental Europe was compared with that in the Canadian-born population using indirect standardization and Poisson models.

RESULTS

Migration from Britain or Continental Europe to Canada in the early twentieth century was associated with an increased rate of schizophrenia; IRR=1.54, (95% CI=1.33-1.78). Incidence increased over time in immigrants but not in the native-born population and this increase occurred during a period of economic recession.

CONCLUSIONS

Migration was a risk factor for schizophrenia a century ago as it is today. This risk occurred in white migrants from Europe and increased during a period of increased social stress.

Environmental factors in schizophrenia: the role of migrant studies

There is now compelling evidence that migrant groups in several countries have an elevated risk of developing schizophrenia and other psychotic disorders. Though the findings of earlier studies were greeted with skepticism, and ascribed by some to have methodological shortcomings and diagnostic biases, the more rigorous recent studies, from a variety of countries, have still found markedly increased incidence rates. While this phenomenon is an important health issue in its own right, understanding the reasons for the increased rates may provide valuable insights into the causes of schizophrenia and other psychotic disorders in general. The challenge for the next phase of studies is to identify the relevant risk factors and how they might interact to increase the risk of psychosis, both in migrant groups and in the general population.

Gender and ethnic differences in urban and rural first-contact schizophrenia outpatients in Trinidad

This study investigated gender and ethnic differences in the rate of first contact outpatients with schizophrenia in the setting of a more-urban region (MUR) and a less-urban region (LUR) in Trinidad. In a prospective study, 134 first-contact patients with a diagnosis of schizophrenia were selected from two ecologically different regions.

RESULTS

Of this population, 56.7% were of African origin and 32.1% were of Indian descent. Gender differences were significant, with males accounting for 66.4% (n=89) of patients with schizophrenia (chi2 = 14.45, d.f. = 1, p = 0.0001). Further analysis by age categories revealed a significant male predominance at ages 20-24 (p = 0.0001) and 25-29 (p = 0.002). Young African males (15-19 y, p = 0.049) predominated in MUR compared with LUR. The results showed a marked presence of Afro-Trinidadian males in both outpatient clinics (p < 0.05). We conclude that gender and ethnicity are important variables in the presentation of schizophrenia in Trinidad, whereas neither rural nor urban environments appeared to influence the expression of schizophrenia.

Genome scan of schizophrenia families in a large Veterans Affairs Cooperative Study sample: evidence for linkage to 18p11.32 and for racial heterogeneity on chromosomes 6 and 14

Genome-wide linkage analyses of schizophrenia have identified several regions that may harbor schizophrenia susceptibility genes but, given the complex etiology of the disorder, it is unlikely that all susceptibility regions have been detected. We report results from a genome scan of 166 schizophrenia families collected through the Department of Veterans Affairs Cooperative Studies Program. Our definition of affection status included schizophrenia and schizoaffective disorder, depressed type and we defined families as European American (EA) and African American (AA) based on the probands' and parents' races based on data collected by interviewing the probands. We also assessed evidence for racial heterogeneity in the regions most suggestive of linkage. The maximum LOD score across the genome was 2.96 for chromosome 18, at 0.5 cM in the combined race sample. Both racial groups showed LOD scores greater than 1.0 for chromosome 18. The empirical P-value associated with that LOD score is 0.04 assuming a single genome scan for the combined sample with race narrowly defined, and 0.06 for the combined sample allowing for broad and narrow definitions of race. The empirical P-value of observing a LOD score as large as 2.96 in the combined sample, and of at least 1.0 in each racial group, allowing for narrow and broad racial definitions, is 0.04. Evidence for the second and third largest linkage signals come solely from the AA sample on chromosomes 6 (LOD = 2.11 at 33.2 cM) and 14 (LOD = 2.13 at 51.0). The linkage evidence differed between the AA and EA samples (chromosome 6 P-value = 0.007 and chromosome 14 P-value = 0.004).

Size of burden of schizophrenia and psychotic disorders

Schizophrenia is a severe mental disorder characterised by fundamental disturbances in thinking, perception and emotions. More than 100 years of research have not been able to fully resolve the puzzle that schizophrenia represents. Even if schizophrenia is not a very frequent disease, it is among the most burdensome and costly illnesses worldwide. It usually starts in young adulthood. Life expectancy is reduced by approximately 10 years, mostly as a consequence of suicide. Even if the course of the illness today is considered more favourable than it was originally described, it is still only a minority of those affected, who fully recover. The cumulative lifetime risk for men and women is similar, although it is higher for men in the age group younger than 40 years. According to the Global Burden of Disease Study, schizophrenia causes a high degree of disability, which accounts for 1.1% of the total DALYs (disability-adjusted life years) and 2.8% of YLDs (years lived with disability). In the World Health Report [The WHO World Health Report: new understanding, new hope, 2001. Geneva], schizophrenia is listed as the 8th leading cause of DALYs worldwide in the age group 15-44 years. In addition to the direct burden, there is considerable burden on the relatives who care for the sufferers. The treatment goals for the moment are to identify the illness as early as possible, treat the symptoms, provide skills to patients and their families, maintain the improvement over a period of time, prevent relapses and reintegrate the ill persons into the community so that they can lead as normal a life as possible.

Risk factors and the prevalence of neurosis and psychosis in ethnic groups in Great Britain

BACKGROUND

Our aim was to examine whether variations in the prevalence of neurosis and psychosis between ethnic minorities throughout Great Britain are explained by social disadvantage.

METHOD

A total of 10,108 adult householders throughout Great Britain were assessed in a two-stage survey with the Revised Clinical Interview Schedule (CIS-R) and Psychosis Screening Questionnaire (PSQ). Respondents with a positive PSQ or who received a diagnosis of, or treatment for, psychosis were examined by a psychiatrist using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). Data on respondents' preferred ethnic group were collapsed into four groups: Whites, African-Caribbean or Africans, south Asians and other.

RESULTS

Ethnic grouping was strongly associated with: unemployment; lone parent status; lower social class; low perceived social support; poverty (indicated by lack of car ownership) and having a primary social support group of less than three close others. All these associations applied to the group Africans and Afro-Caribbeans, but only some applied to the other groups. No ethnic group had significantly increased rates of neurosis. Only the African-Caribbean group were at significantly increased risk of a psychotic disorder (odds ratio 4.55; 95% CI: 1.13, 18.30). After adjustment for risk factors, the odds of psychosis were lower (odds ratio 2.97; 95% CI: 0.66, 13.36).

CONCLUSIONS

The excess of psychosis in Africans and Afro-Caribbeans in Great Britain appears to be partly explained by socio-economic disadvantage, but larger studies are needed to confirm this.

Migration and mental health

OBJECTIVE

Migration and its accompanying stressors affect migrating individuals and their families. The process of migration is not simple or straightforward. The aim of this review is to distil existing information on how migration influences individuals' mental state and how it determines help seeking as well as pathways to care.

METHOD

The review relies on published studies in both MEDLINE and non-MEDLINE journals as well as relevant monographs. The search was employed using migration, ethnic communities, stress and other relevant words for purposes of the review.

RESULTS

The review provides a background on the typology of migration, its impact on communities as well as individuals. Furthermore, the relationship of mental illness to migration is explored and described. Future research plans are advocated in relationship with these findings.

CONCLUSION

Migration is and can be a very stress-inducing phenomenon. Yet not all migrants go through the same process. The clinician needs to be aware of coping strategies as well as resilience among migrants.

Is there an association between the use of heeled footwear and schizophrenia?

Existing etiological and pathogenetical theories of schizophrenia have only been able to find support in some epidemiological, clinical, and pathophysiological facts. A selective literature review and synthesis is used to present a hypothesis that finds support in all facts and is contradicted by none. Heeled footwear began to be used more than a 1000 years ago, and led to the occurrence of the first cases of schizophrenia. Industrialization of shoe production increased schizophrenia prevalence. Mechanization of the production started in Massachusetts, spread from there to England and Germany, and then to the rest of Western Europe. A remarkable increase in schizophrenia prevalence followed the same pattern. In Baden in Germany the increasing stream of young patients more or less hastily progrediating to a severe state of cognitive impairment made it possible for Kraepelin to delineate dementia praecox as a nosological entity. The patients continued to use heeled shoes after they were admitted to the hospitals and the disease progrediated. High rates of schizophrenia are found among first-generation immigrants from regions with a warmer climate to regions with a colder climate, where the use of shoes is more common. Still higher rates among second-generation immigrants are caused by the use of shoes during the onset of walking at an age of about 11-12 months. Other findings point to the importance of this in the later development of schizophrenia. A child born in January-March begins to walk in December-March, when it's cold outside and the chances of going barefoot are smaller. They are also smaller in urban settings. During walking synchronised stimuli from mechanoreceptors in the lower extremities increase activity in cerebello-thalamo-cortico-cerebellar loops through their action on NMDA-receptors. Using heeled shoes leads to weaker stimulation of the loops. Reduced cortical activity changes dopaminergic function which involves the basal ganglia-thalamo-cortical-nigro-basal ganglia loops. Bicycle riding reduces depression in schizophrenia due to stronger stimulation by improved lengthening contractions of the triceps surae muscles. Electrode stimulation of cerebellar loops normally stimulated by mechanoreceptors in the lower extremities could improve functioning in schizophrenia. Cross-sectional prevalence studies of the association between the use of heeled footwear and schizophrenia should be made in immigrants from regions with a warmer climate or in groups of people who began to wear shoes at different ages.

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.

Incidence of schizophrenia in ethnic minorities in London: ecological study into interactions with environment

OBJECTIVE

To determine whether the incidence of schizophrenia among people from non-white ethnic minorities is greater in neighbourhoods where they constitute a smaller proportion of the total population.

DESIGN

Ecological design including retrospective study of case records to calculate the incidence of schizophrenia in the ethnic minority population across electoral wards and multi-level analysis to examine interaction between individuals and environment.

SETTING

15 electoral wards in Camberwell, South London.

PARTICIPANTS

All people aged 16 years and over who had contact with psychiatric services during 1988-97.

MAIN OUTCOME MEASURE

Incidence rates of schizophrenia according to Research Diagnostic Criteria.

RESULTS

The incidence of schizophrenia in non-white ethnic minorities increased significantly as the proportion of such minorities in the local population fell. The incidence rate ratio varied in a dose-response fashion from 2.38 (95% confidence interval 1.49 to 3.79) in the third of wards where non-white ethnic minorities formed the largest proportion (28-57%) of the local population to 4.4 (2.49 to 7.75) in the third of wards where they formed the smallest proportion (8-22%).

CONCLUSION

The incidence of schizophrenia in non-white ethnic minorities in London is greater when they comprise a smaller proportion of the local population.