Psychosis Rates Higher In Immigrant Groups In London


A higher risk of psychosis is found in first and second generation immigrants to the United Kingdom, in comparison to white British people, according to a report released on November 3, 2008 in Archives of General Psychiatry, one of the JAMA/Archives journals.

Psychosis is a serious manifestation of mental illness that is associated with disorders such as schizophrenia which are characterized by an interruption with reality. Generally, schizophrenia is considered to have uniform prevalence among world populations, with some potential genetic influence. However, higher rates of psychoses were been observed in migrant groups as early as 1932 when a Norwegians moving to the United States showed higher incidence rates, according to the article. “Immigration is an important life event and difficulties in assimilation may remain chronic as conceptualized within the stress-vulnerability model of risk for psychosis, although individual risk is still considered to be mediated through genetic susceptibility,” write the authors.

To investigate the potential association between immigration and psychotic disorders, Jeremy W. Coid, M.D., of St. Bartholomew’s Hospital, London, and colleagues examined 484 patients in innder-city East London who had first psychotic episodes between 1996 and 2000. Information was collected about the patients regarding ethnicity, place of birth, and parents’ place of birth. The ethnic subgroups included white British, white “other” (such as Irish and European), black Caribbean, black African, Asian (such as Indian, Pakistani and Bangladeshi group) and all other groups (including Chinese, other Asian and those of mixed ethnicity.) The subjects ranged in age from 18 to 64 years.

The researchers found that all types of psychoses were increased for certain subgroups. Raised incidence of both non-affective [not related to emotion or mood] and affective psychoses were found for all of the black and minority ethnic subgroups compared with white British individuals,” they write. “The risk of non-affective psychoses for first and second generations varied by ethnicity.” The latter can be seen in the example of black Caribbean second-generation immigrants, who were at higher risk for psychoses than first-generation counterparts of the same ethnicity. In contrast, Asian women had an increased risk in comparison to white British individuals, while Asian men had no increased risk.

The authors note a powerful influence on the rate of psychoses in these groups: age. The black Caribbean group provides an illustration of this: first- and second-generation immigrants were both at significantly greater risk for non-affective psychoses than the white British group, but the magnitude of this risk was significantly greater in the second generation; this is principally because first-generation black Caribbean immigrants have now largely passed through the main period of risk of psychoses,” they write.

Additionally, the authors point out many important factors that are associated with immigration that could also lead to psychotic symptoms, even after correcting for age. These might include discrimination, isolation, or alienation. “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 authors write. “We suggest that socioenvironmental factors operate differentially by ethnicity but not generation status, even if the exact specification of these stressors differs across generations. Research should focus on differential rates of psychoses by ethnicity rather than between generations.”

Raised Incidence Rates of All Psychoses Among Migrant Groups: Findings From the East London First Episode Psychosis Study
Jeremy W. Coid, MD; James B. Kirkbride, PhD; Dave Barker, MRCPsych; Fiona Cowden, MRCPsych; Rebekah Stamps, MRCPsych; Min Yang, MD, MPH; Peter B. Jones, PhD
Arch Gen Psychiatry. 2008;65(11):1250-1258.
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Written by Anna Sophia McKenney