Point prevalence of schizophrenia in immigrant groups in Rotterdam: data from outpatient facilities.

OBJECTIVE: Reports of an increased incidence of schizophrenia in some immigrant groups to The Netherlands are based exclusively on hospital data. The aims of our study were: 1) to determine the treated point prevalence of schizophrenia at outpatient mental health services in Rotterdam and to compare the results for immigrants to those for natives; and 2) to compare groups born in The Netherlands and immigrant groups in terms of the proportions of patients with a previous hospital admission. METHOD: We included all patients aged between 20 and 64 who were treated for a non-affective psychosis at any of the outpatient mental health services in Rotterdam on October 1, 1994. The mental health professionals responsible reported on the socio-demographic and clinical characteristics of each patient. RESULTS: Seven hundred and thirteen patients with a diagnosis of schizophrenia (DSM-III-R) were identified (rate: 2.1 per 1000). The (treated) prevalence of schizophrenia in male immigrants from Surinam and Morocco and in female immigrants from Surinam, the Netherlands Antilles and Cape Verde was significantly higher than that in their native-born counterparts (odds ratios between 2 and 3). The (treated) prevalence was not significantly higher in immigrants from Turkey, female immigrants from Morocco or male immigrants from the Antilles. Proportions of patients with a previous hospital admission were similar in each ethnic group (81-93%). CONCLUSION: These findings are generally in line with earlier studies, based on the Dutch psychiatric registry, which has reported an increase in the (treated) incidence of schizophrenia in immigrants from Surinam and the Netherlands Antilles and in male immigrants from Morocco, and no increase in the (treated) incidence in immigrants from Turkey or female immigrants from Morocco.     

First admissions for mood disorders in immigrants to the Netherlands

BACKGROUND: The risk of developing schizophrenia is increased for immigrants to the Netherlands from Surinam, the Netherlands Antilles and Morocco, but not for immigrants from Turkey. We examined, in these groups, the risks of a first admission for manic-depressive psychosis. METHODS: The Dutch Psychiatric Registry provided two datasets. The first referred to first admissions for manic-depressive psychosis (MDP), manic or circular type, in the period 1990-1996, the second to first admissions for MDP, depressed type. MDP, depressed type, corresponds (broadly) to the DSM-IV category of major depressive disorder and MDP, manic or circular type, to the DSM-IV category of bipolar I disorder. The Dutch Central Bureau for Statistics provided yearly population figures. RESULTS: There were only small increases in the risks of a first admission for MDP, manic or circular type, for immigrants from Surinam (age- and sex-adjusted RR = 1.14; 95% CI: 0.97-1.33) and the Netherlands Antilles (RR = 1.41; 1.10-1.80). This risk was not clearly increased for immigrants from Morocco. The risks for MDP, depressed type, were increased for males from Morocco (age-adjusted RR = 2.17; 1.72-2.72) and Turkey (RR = 1.83; 1.46-2.30), and significantly decreased for females in all of the immigrant groups. CONCLUSION: We found no evidence for a large increase in the incidence of MDP, manic or circular type, in the immigrant groups, whereas an increase in MDP, depressed type, was observed only in selected groups. Female immigrants suffering from MDP, depressed type, may be underserved.     

Treatment seeking for alcohol and drug use disorders by immigrants to the Netherlands

Background We compared risks of first contact with services for an alcohol use disorder (AUD) or drug use disorder (DUD) between the largest immigrant groups to the Netherlands and Dutch nationals. We tested the hypothesis that the ethnic pattern for DUD is similar to the previously demonstrated pattern for schizophrenia. Methods Retrospective, population-based cohort study of First Admissions to Dutch psychiatric hospitals during the period 1990–1996 (national data) and First Contacts with inpatient or outpatient centres in Rotterdam for treatment of AUD or DUD during the period 1992–2001 (Rotterdam data). Results In both datasets the risk of service contact for AUD was significantly lower in immigrants from Surinam, Turkey and Morocco than in Dutch nationals. The risk was lower or moderately higher in immigrants from western countries. Analysis of the national data showed that, compared with Dutch males, the risk of first hospital admission for DUD was higher for male immigrants from the Dutch Antilles (RR = 4.6; 95% CI: 4.0–5.3), Surinam (RR = 4.3; 3.9–4.7) and Morocco (RR = 2.3; 2.0–2.6), but not for male immigrants from Turkey (RR = 0.9; 0.7–1.1). A similar pattern was found with the Rotterdam data. Female immigrants from Surinam and the Dutch Antilles had a higher risk for DUD according to the national data, but a lower risk according to the Rotterdam data. Female immigrants from Turkey and Morocco had a lower risk (both datasets). Immigrants from western countries had a higher risk for DUD, but many had developed the disorder before emigrating. Conclusion Those immigrant groups in the Netherlands that are at increased risk of schizophrenia appear also at increased risk of developing DUD, but not AUD.     

Ødegaard's selection hypothesis revisited: schizophrenia in Surinamese immigrants to The Netherlands

OBJECTIVE: The incidence of schizophrenia among Surinamese immigrants to the Netherlands is high. The authors tested ?degaard's hypothesis that this phenomenon is explained by selective migration. METHOD: The authors imagined that migration from Surinam to the Netherlands subsumed the entire population of Surinam and not solely individuals at risk for schizophrenia. They compared the risk of a first admission to a Dutch mental hospital for schizophrenia from 1983 to 1992 for Surinamese-born immigrants to the risk for Dutch-born individuals, using the Surinamese-born population in the Netherlands and the population of Surinam combined as the denominator for the immigrants. RESULTS: The age- and sex-adjusted relative risk of schizophrenia for the Surinamese-born immigrants was 1.46. CONCLUSIONS: Selective migration cannot solely explain the higher incidence of schizophrenia in Surinamese immigrants to the Netherlands.     

Symptoms at first contact for psychotic disorder: comparison between native Dutch and ethnic minorities

The incidence of schizophrenia and other psychotic disorders is very high among several ethnic minority groups in the Netherlands, and is most increased for Moroccans. This study compared symptoms at first treatment contact for a psychotic disorder between 117 native Dutch and 165 ethnic minority patients from Morocco, Surinam, Turkey, other non-Western countries and Western countries, using data from an incidence study for psychotic disorders over 4 years in The Hague, the Netherlands (1997-1999 and 2000-2002). Patients were examined using the Comprehensive Assessment of Symptoms and History (CASH), which includes the Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), and a section on DSM-IV mood disorders. Differences between native Dutch and ethnic minorities in SAPS, SANS, total psychopathology (SAPS plus SANS), proportions of patients meeting the criteria for a current manic or depressive episode, and differences in individual symptoms were investigated using regression analyses. Moroccans had higher total psychopathology and total SANS scores than native Dutch, and particularly presented more often with persecutory delusions. Moroccans and Turks more often met the criteria for a depressive episode. The other ethnic groups did not differ from native Dutch in levels of psychopathology. These results suggest that Moroccans not only have the highest risk of schizophrenia of all ethnic groups in The Hague, but that they are also more severely ill at first treatment contact. Experiences of social adversity, which have been associated with persecutory delusions, and cultural factors may contribute to the observed differences in severity and content of psychopathology between Moroccans and native Dutch.     

Differences in age of first hospitalization for schizophrenia among immigrants and nonimmigrants in a national case registry

While previous studies have found an increased incidence of schizophrenia in some immigrant groups, differences in age of onset in these groups has not been examined. The purpose of this study was to compare age of first hospitalization of (1) native-born people versus immigrants, (2) immigrants from different countries of origin, and (3) first generation immigrants versus second generation immigrants; and to reexamine gender differences in age of first hospitalization. Data were extracted on all first hospital admissions nationally for the years 1978-1992 (n = 10,902) from the National Psychiatric Hospitalization Case Registry of the State of Israel Ministry of Health. Immigrants were older at time of first hospitalization than nonimmigrants, with considerable variations between different countries of origin. Second generation immigrants (i.e., born in Israel to immigrant parents) had ages of first hospitalization similar to people with native-born parents. Males had earlier ages at first hospitalization than females. The results suggest that immigration may have a delaying effect on age of first admission and support previous findings regarding gender difference in age of onset.     

Incidence of schizophrenia in Surinam

More than one-third of the population of Surinam has migrated to The Netherlands in the 1970s and 1980s. If selective migration explains the increased incidence in these migrants, one expects to find a very low incidence of the disorder in Surinam. We examined the medical records of the sole psychiatric hospital in Surinam and found that the mean annual rate of first admissions for schizophrenia or schizophreniform disorder (DSM-III-R criteria) in 1992 and 1993 was 1.61 per 10,000 (95% Confidence interval: 1.24-1.98 per 10,000), a normal figure. These findings constitute a challenge to the hypothesis that selection explains the increased incidence in the migrants. The possibility of an increased incidence of the disorder in Surinam (which might also explain the increased incidence among migrants) has not been ruled out by the results of this study.     

Ethnic density of neighborhoods and incidence of psychotic disorders among immigrants

OBJECTIVE: A high incidence of psychotic disorders has been reported in immigrant ethnic groups in Western Europe. Some studies suggest that ethnic density may influence the incidence of schizophrenia. The authors investigated whether this increased incidence among immigrants depends on the ethnic density of the neighborhoods in which they live. METHOD: This was a prospective first-contact incidence study of psychotic disorders in The Hague, by ethnicity and neighborhood of residence. Over a 7-year period, individuals who made contact with a physician for a suspected psychotic disorder underwent diagnostic interviews and received DSM-IV diagnoses. A comprehensive municipal registration system provided the denominator for incidence rates. Data were sufficient to examine incidence rates in native Dutch and in first- and second-generation immigrants from Morocco, Suriname, and Turkey. The ethnic density of a neighborhood was computed for each immigrant group as the proportion of residents belonging to that group. Multilevel regression analyses predicted the incidence of psychotic disorders as a function of individual ethnicity and neighborhood ethnic density. Models were fitted for all immigrants together and for each immigrant group separately. RESULTS: A total of 226 native Dutch and 240 immigrants were diagnosed as having a psychotic disorder. Compared with native Dutch, the adjusted incidence rate ratio for immigrants was significantly increased in low-ethnic-density neighborhoods (2.36) but not in high-ethnic-density neighborhoods (1.25). There was a strong interaction between individual ethnicity and neighborhood ethnic density as predictors of incidence of illness. These findings were consistent across all immigrant groups. CONCLUSIONS: The incidence of psychotic disorders was elevated most significantly among immigrants living in neighborhoods where their own ethnic group comprised a small proportion of the population.     

Cognitive deficits and ethnicity: a cohort study of early psychosis patients in The Netherlands

Purpose

Incidence rates of psychotic disorders are higher in immigrant groups compared to native populations. This increased risk may partly be explained by misdiagnosis. Neurocognitive deficits are a core feature of psychotic disorders, but little is known about the relationship between migration and cognition in psychotic disorders. We examined whether immigrant patients have cognitive deficits similar to non-immigrant patients, in order to investigate the plausibility of misdiagnosis as explanation for increased incidence rates.

Methods

Patients who made first contact for non-affective psychotic disorder were assessed in the cognitive domains sustained attention, immediate recall and delayed recall. Immigrant patients were compared to Dutch patients on cognitive performance.

Results

407 Patients diagnosed with a non-affective psychotic disorder completed cognitive assessment (157 Dutch, 250 immigrants). Both Dutch and immigrant patients showed large cognitive deficits. Between-subgroup comparisons revealed large cognitive deficits for immigrants compared to Dutch, especially for immigrants from Morocco, Turkey and other non-Western countries.

Conclusions

These results indicate that immigrant status is associated with poorer cognitive functioning in early psychosis. The findings argue against diagnostic bias as an explanation for the increased incidence of psychotic disorders in immigrants.     

Ethnic disadvantage and schizophrenia

OBJECTIVE: To review and interpret epidemiologic research on ethnic disadvantage and schizophrenia. METHOD: A search of the research literature was conducted. RESULTS: Seventeen population-based studies were reported in the United Kingdom and the Netherlands from 1967 to 1997. The studies report high incidence rates for immigrants whose position in society is disadvantaged, than majority-group native-born, with a range of relative incidence from 1.7 to 13.2. It is proposed that the developmental task for formulating the life plan challenges the young adult's executive function abilities, which may be weaker in individuals vulnerable to schizophrenia. Formulating the life plan may be made more difficult by the position in society of disadvantaged ethnic minorities, raising the risk for schizophrenia. CONCLUSION: Further research on executive function, and the developmental challenge of formulating the life plan, might provide insights into the etiology of schizophrenia, as well as suggest avenues for prevention.     

Ethnic origin and increased risk for schizophrenia in immigrants to countries of recent and longstanding immigration

Dealberto M‐J. Ethnic origin and increased risk for schizophrenia in immigrants to countries of recent and longstanding immigration. Objectives: Compare the risk for schizophrenia in immigrants to countries of recent and longstanding immigration. Compare prevalence and incidence rates in black subjects under different conditions. Method: An electronic literature search was complemented by review articles and cross‐references. Studies reporting standard diagnosis and incidence or prevalence rates were included. Results: Immigrants had an increased risk for schizophrenia in countries of longstanding immigration, but with lower risk ratios than in those of recent immigration. The risk was higher in black immigrants and the black population living in the United States. But incidence and prevalence rates in Africa and the Caribbean were similar to those of international studies. Conclusion: Comparing the most recent generation of immigrants with descendants of previous ones may account for the lower risk ratios observed in countries of longstanding vs. recent immigration. Two neurobiological hypotheses are proposed to explain the epidemiological findings in black populations and in immigrants.     

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.     

Immigrants and refugees: the psychiatric perspective

Psychiatric studies of immigrants have yielded contradictory findings regarding rates of mental illness. Current evidence suggests that rates of schizophrenia (and probably other disorders) among immigrant groups are low compared with native-born populations when sending and receiving countries are socially and culturally similar. The rates for immigrants are higher when sending and receiving countries are dissimilar, probably because of multiple social problems faced by immigrants in the receiving country. Refugees who flee their own country because of fears of violence or starvation often have had extremely traumatic experiences, which may result in PTSD and sometimes chronic impairment. Asylum seekers who arrive illegally to seek refuge in a foreign country also may have multiple traumas and experience further distress from their uncertain residency and legal status. Although much is known about the effects of migration, competent culturally sensitive services for migrants remain inadequate to meet the need.     

Incidence of schizophrenia among ethnic minorities in the Netherlands: a four-year first-contact study

There is only one previous report on the first-contact incidence of schizophrenia among immigrants in the Netherlands, which was based on a small number of cases, particularly for second generation immigrants. We conducted another two-year first-contact incidence study in the same geographical area, combined the data of both studies and compared risks over all four years. The incidence of schizophrenia was increased for all first generation non-Western immigrants. The risk was particularly high for second generation immigrants: the age- and gender-adjusted incidence rate ratio was 5.8 (95% CI, 2.9-11.4) for Moroccans, 2.9 (1.6-5.0) for Surinamese, 2.3 (1.0-5.4) for Turks, and 3.5 (1.8-6.8) for immigrants from other non-Western countries.     

Increase in first admissions for schizophrenia and other major psychoses in Italy

Despite reports of falling first-admission rates for schizophrenia in some Western countries, methodological problems and bias preclude a definite conclusion about a genuine fall in the incidence of schizophrenia. This study set out to test the hypothesis that first admissions for schizophrenia in Italy have fallen in recent years. All admissions rated as 'first contact' in Italy from 1984 to 1994 for severe mental illnesses to general hospital psychiatric services, as reported in the Italian National Institute for Statistics Health-Care Yearbooks, were considered. Data were analyzed as rates per 100000 in the general population, and changes over time in incidence of schizophrenia, paranoia, affective psychoses and drug-induced psychoses (diagnosed according to ICD 9) were recorded. Changes in rates over time, with rates as the dependent variable and years as the independent variable, were the main outcome measure. First-admission rates for schizophrenia and paranoia increased progressively from 1984 to 1994, as did those for affective psychoses, mania and, to a lesser extent, major depression. In the same period, all admissions (both total and rated as 'first-contact') for mental disorders increased. Although linear regression tests for admission rates in most, but not all, cases indicate a significant ascending linear trend, quadratic model results show a significantly better fit than does the simple linear regression model for the majority of data. The change described by the quadratic model suggests an increase in admission rates more marked in the second half than in the first half of the period of the study. First-admission rates for schizophrenia and, to a lesser extent, paranoia seemed to increase concurrent to a decrease in first-admission rates for 'other' non-organic psychoses. Contrary to reports from other Western countries, hospital incidence in Italy for schizophrenia is on the increase, as is that for other severe psychoses. This increase is likely to be a reflection of changes in mental health-care organisation, in treatment and diagnostic patterns, and in cultural attitudes towards mental illness. Radical changes in the true incidence of psychoses, in particular of mood disorders, as described elsewhere, cannot be ruled out as contributing factors. Data bias and limitations preclude a generalisation of results, however.     

Mental illness in immigrants to England and Wales: An analysis of mental hospital admissions, 1971

Summary A study has been made of all admissions to mental hospitals in England and Wales in 1971 by place of birth. After age/sex standardization of rates and reallocating those patients for whom place of birth was not recorded to appropriate categories, several surprising findings emerged. Compared to the native born, those born in Ireland and Scotland had very high rates of mental hospital admission. Poles also had high rates but West Indians and those born in the U. S. A. had rates comparable to the native born. Rates of mental hospital admission for immigrants from India, Pakistan, Germany and Italy were much lower than native born rates. All immigrant groups studied had higher rates of admission for schizophrenia than natives but much of this discrepancy can be explained by the age structures of the populations being compared. The Irish and Scots had extremely high rates of alcohol and drug related disorders and personality and behaviour disorders but West Indians were underrepresented in these diagnostic categories. Various explanations for these and other results are considered and it is concluded that the most tenable hypothesis is one of differential selection for migration — where migration is relatively easy the less stable members of a population self select for migration but where migration is relatively difficult only the most stable individuals can achieve migration.     

The impact of immigration on psychiatric hospitalization in Illinois from 1993 to 2003

OBJECTIVE: Illinois public hospitalizations over a ten-year period were studied to determine the impact of recent immigration. The study also explored clinical and demographic differences between immigrant groups and native-born Americans. METHODS: Information was collected from the state hospital Clinical Information System for 1993, 1998, and 2003. Variables included age, sex, race, marital status, education, diagnosis, length of stay, birthplace, citizenship, primary language, English proficiency, and availability of a Social Security number. Logistic multiple regression was used to analyze trends in the proportion of psychiatric admissions of foreign-born patients, with foreign born as the dependent variable and year as the independent variable. Chi square analysis was used for trends across time. RESULTS: In the hospitalized population, the proportion of immigrants was 7.3% in 1993, 10.9% in 1998, and 13.1% in 2003. With covariates adjusted for, the average increase of 8.0% per year in the odds of being foreign born was statistically significant (odds ratio=1.08, 95% confidence interval=1.06-1.10). Nevertheless, the proportion of foreign-born hospital admissions, including Asian and Mexican immigrants, was below their population ratio in Illinois. Mexican-origin immigrants constituted the largest group of admissions and were younger, less educated, had poorer English skills, and were more likely to be undocumented than other immigrants. CONCLUSIONS: The percentage of foreign-born patients admitted was lower than their percentage in the overall population. In previous immigration waves, immigrants were hospitalized at disproportionately higher rates than nonimmigrants. The gap is slowly narrowing as new admissions are increasingly likely to be foreign born, suggesting that public psychiatric hospitals should prepare for these changing populations.     

Cross-cultural adaptation and mental disorders]

Recently, it has not been rare for psychiatrists to treatment disorders and provide consultation on mental health problems for people from different cultures. The following is a brief outline of mental disorders and mental health problems of the people who immigrated in culturally different societies. In reviewing the literature, most of the reports demonstrate that the admission rate for schizophrenia is higher among immigrants than among people remaining in their original countries or among native-born people of the host countries. Furthermore the prevalence of mood disorders in community surveys is reported to be higher among immigrants than among native-born people of the host countries. In regard to gender difference of vulnerability to cross-cultural immigration, the prevalence rate for mental disorders is reported to be higher in female immigrants than male immigrants. Psychological adaptation of Japanese war orphans returned from Mainland China four decades after WWII revealed that psychological problems became exacerbated three months after resettlement in Japan and took three years to recover. Three major psychological symptoms that manifested in resettlement were obsession, somatization and depression. It is hypothesized that the acculturation process can be divided into four layers: the behavioral level, intellectual level, representative level and emotional level. The study of the acculturation process of Japanese war orphans demonstrated that it gradually proceeded from a surface level to deeper levels, namely from the behavioral level-->intellectual level-->representative level-->emotional level. The relationship of psychological adaptation and acculturation process is reported to be complicated. The acculturation process does not necessarily accompany psychological adaptation and vice versa. Impact of immigration on psychological manifestation revealed the following vicissitude: the asymptomatic phase for two months after resettlement-->hypochondriacal phase-->depressive phase-->paranoid phase. The vicissitude of psychological manifestations of the impact of immigration may be a reflection of the four layers of adaptive mechanisms (G. Vaillant).     

Multiple sclerosis: genetic versus environmental aetiology: epidemiology in Israel updated

The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups.     

Time trends in first admissions for schizophrenia and paranoid psychosis in Stockholm County, Sweden

Several studies have reported decreasing time trends in first diagnosed schizophrenia patients. The aim of this study was to analyze time trends for first admissions with a diagnosis of schizophrenia or a diagnosis of either schizophrenia or paranoid psychosis during 1978-1994 in Stockholm County, Sweden, with a population of around 1.8million. Information about first psychiatric admission with the diagnosis schizophrenia or paranoid psychosis for residents of Stockholm County was obtained from the Swedish population-based psychiatric inpatient register. Age-adjusted average yearly changes in first hospitalization rates were estimated in a Poisson regression model. Time trends in first admission rates were calculated from 1978 to 1994, while admissions during 1971 to 1977 were observed only to eliminate later re-admissions. First admissions for schizophrenia declined by 1.9% annually for females and by 1.3% for males, while first admissions for schizophrenia and paranoid psychosis together were unchanged over the study period for both genders. Our results indicate that the incidence of schizophrenia and paranoid psychosis taken together was essentially the same over the studied time period in Stockholm County, and that the apparent decline in first admission rates for schizophrenia may be an effect of changes in clinical diagnosis over time.