Archief Roodbont

Marlene Busko

Medscape Medical News 2008. © 2008 Medscape

November 11, 2008 — Risk for psychosis is higher in first- and second-generation immigrants to Britain than in white British-born individuals, but risk varies by ethnicity, new research suggests.

"All [other] ethnic groups, whether they are immigrants or not, are at greater risk of psychosis than British-born whites," lead author Jeremy W. Coid, MD, from St. Bartholomew's Hospital, in London, told Medscape Psychiatry.

"This work identifies populations with higher rates of psychoses who have a need for more mental health resources," he added.

These findings, from the East London First Episode Psychosis Study, are published in the November issue of the Archives of General Psychiatry.

Schizophrenia Higher Among Blacks in the United Kingdom

In addition to stress caused by the life-altering event of immigration itself, immigrants and their children are likely to face discrimination and social exclusion, said Dr. Coid.

These socioeconomic factors may combine with genetic factors to push an individual over the threshold for a psychotic illness. On the other hand, individuals in certain ethnic groups may be protected from some of these stresses by having strong religious, cultural, and family support networks.

"For instance, among second-generation United Kingdom–born individuals, the risk of psychosis is elevated for men and women of African and Caribbean origin, but not for South Asian men, perhaps because of the buffering effects of family and cultural lifestyles in this subgroup," said Dr. Coid

Previous studies reported that blacks of Caribbean origin living in the United Kingdom and their United Kingdom–born children had higher rates of schizophrenia compared with blacks living in the Caribbean. On the other hand, this increased prevalence of psychosis has not been consistently found in Asian immigrants from the Indian subcontinent, the largest immigrant group to the United Kingdom.

To investigate the incidence and types of psychoses across different immigrant groups and generations, the researchers examined individuals living in East London, an area with the highest numbers of socioeconomically deprived individuals in the United Kingdom.

Deprived Inner-City Dwellers

The eligible study population included over 800,000 individuals aged 18 to 64 years living in 3 neighboring inner-city London boroughs over a 24-month period during the late 1990s.

The researchers identified 484 individuals who presented to psychiatric services for a first episode of psychosis.

More than 55% of the individuals had schizophrenia, one-quarter had affective psychoses (with prominent mood symptoms), and close to 20% had a nonaffective psychosis other than schizophrenia.

Participants were categorized according to 1 of 6 ethnic groups: white British, white other (primarily Irish or European), black Caribbean, black African, Asian (Indian, Pakistani, and Bangladeshi groups), or other (Chinese, other Asian, or other groups).

More than 95% of the white British individuals were born in the United Kingdom.

First-generation black Caribbean immigrants were older than other first-generation immigrants, since most had emigrated from the Caribbean in the 1950s and 1960s, whereas other ethnic groups were more recent immigrants.

Research Agenda Shift

Both first- and second-generation immigrants were at increased risk for both nonaffective and affective psychoses.

Blacks from the Caribbean, followed by blacks from Africa and to a lesser extent non-British whites and Asians, but not "other" minorities, all had a significantly higher risk for psychoses than native white British individuals.

Children of blacks who emigrated from the Caribbean had a significantly higher risk for nonaffective psychosis than their parents, whereas there was no significant generational difference in incidence of nonaffective psychosis among other minority groups. This was mainly because first-generation blacks from the Caribbean, unlike the other newer immigrant groups, have now largely passed beyond the age range with greatest risk for first psychosis, said Dr. Coid.

Both first- and second-generation Asian women had higher incidence rates of nonaffective psychosis compared with their white British counterparts, but Asian men did not, possibly due to protective factors in social or family structures.

"Our results suggest that given the same age structure, the risk of psychoses in first and second generations of the same ethnicity will be roughly equal," the researchers write.

"We suggest that socioenvironmental factors operate differentially by ethnicity but not by generation status, even if the exact specification of these stressors differs across generations," they add.

"These findings shift the research agenda in a different direction," said Dr. Coid. Rather than look at generational differences, research into the incidence of psychosis among immigrants should focus on ethnicity and different protective factors among different minority groups.

The study was funded by grants from St. Bartholomew’s Hospital and the Royal London Hospital Special Trustees and East London and the City Mental Health NHS Trust R&D. The study authors report no relevant disclosures.

Arch Gen Psychiatry. 2008;65:1250-1258. Abstract