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A meta-analysis of the risk for psychotic disorders among first- and second-generation immigrants

Published online by Cambridge University Press:  21 July 2010

F. Bourque ,
E. van der Ven  and
A. Malla
F. Bourque*
Affiliation:
Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Canada
E. van der Ven
Affiliation:
Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Canada
A. Malla
Affiliation:
Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Canada
*
*Address for correspondence: F. Bourque, M.D., M.Sc., F.R.C.P.C., Prevention and Early Intervention Program for Psychoses, Douglas Mental Health University Institute, 6875, LaSalle Boulevard, Montreal QC, Canada H4H 1R3. (Email: francois.bourque@mail.mcgill.ca)
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Abstract

Background

There is increasing acceptance of migration as a risk factor for schizophrenia and related disorders; however, the magnitude of the risk among second-generation immigrants (SGIs) remains unclear. Generational differences in the incidence of psychotic disorders among migrants might improve our understanding of the relationship between migration, ethnicity and psychotic disorders. This meta-analysis aimed at determining the risk of psychotic disorders among SGIs in comparison with non-migrants and first-generation immigrants (FGIs).

Method

Medline, EMBASE and PsycINFO databases were searched systematically for population-based studies on migration and psychotic disorders published between 1977 and 2008. We also contacted experts, tracked citations and screened bibliographies. All potential publications were screened by two independent reviewers in a threefold process. Studies were included in the meta-analysis if they reported incidence data, differentiated FGIs from SGIs and provided age-adjusted data. Data extraction and quality assessment were conducted for each study.

Results

Twenty-one studies met all inclusion criteria. A meta-analysis of 61 effect sizes for FGIs and 28 for SGIs yielded mean-weighted incidence rate ratios (IRRs) of 2.3 [95% confidence interval (CI) 2.0–2.7] for FGIs and 2.1 (95% CI 1.8–2.5) for SGIs. There was no significant risk difference between generations, but there were significant differences according to ethno-racial status and host country.

Conclusions

The increased risk of schizophrenia and related disorders among immigrants clearly persists into the second generation, suggesting that post-migration factors play a more important role than pre-migration factors or migration per se. The observed variability suggests that the risk is mediated by the social context.

Keywords

Ethnicitymeta-analysismigrationpsychosisschizophrenia
Type
Review Article
Information
Psychological Medicine , Volume 41 , Issue 5 , May 2011 , pp. 897 - 910
Copyright
Copyright © Cambridge University Press 2010

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References

Alarcón, RD, Bell, CC, Kirmayer, LJ, Lin, KM, Üstün, B, Wisner, KL (2002). Beyond the funhouse mirrors. Research agenda on culture and psychiatric diagnosis. In A Research Agenda for DSM-V (ed. Kupfer, D. J., First, M. B. and Regier, D. A.), pp. 219–290. American Psychiatric Association: Washington, DC.Google Scholar
Bebbington, PE, Hurry, J, Tennant, C (1981). Psychiatric disorders in selected immigrant groups in Camberwell. Social Psychiatry 16, 43–51.CrossRefGoogle Scholar
Bhui, K, Tsangarides, N (2008). Culture and schizophrenia. Psychiatry 7, 454–457.CrossRefGoogle Scholar
Borenstein, M (2010). Meta-Analysis: Computing Treatment Effects and Effect Sizes. Wiley: Chichester.Google Scholar
Borenstein, M, Hedges, LV, Higgins, JPT (2005). Comprehensive Meta-analysis Version 2. Biostat: Englewood, NJ.Google Scholar
Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR (2009 a). Effect sizes based on binary data (2×2 tables). In Introduction to Meta-Analysis, pp. 33–40. Wiley: Chichester.CrossRefGoogle Scholar
Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR (2009 b). Fixed-effect versus random-effects models. In Introduction to Meta-Analysis, pp. 77–86. Wiley: Chichester.CrossRefGoogle Scholar
Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR (2009 c). Identifying and quantifying heterogeneity. In Introduction to Meta-Analysis, pp. 107–126. Wiley: Chichester.CrossRefGoogle Scholar
Boydell, J, van Os, J, McKenzie, K, Allardyce, J, Goel, R, McCreadie, RG, Murray, RM (2001). Incidence of schizophrenia in ethnic minorities in London: ecological study into interactions with environment. British Medical Journal 323, 1336–1338.CrossRefGoogle ScholarPubMed
Cantor-Graae, E (2007). The contribution of social factors to the development of schizophrenia: a review of recent findings. Canadian Journal of Psychiatry 52, 277–286.CrossRefGoogle Scholar
Cantor-Graae, E, Pedersen, CB (2007). Risk of schizophrenia in second-generation immigrants: a Danish population-based cohort study. Psychological Medicine 37, 485–494.CrossRefGoogle ScholarPubMed
Cantor-Graae, E, Pedersen, CB, McNeil, TF, Mortensen, PB (2003). Migration as a risk factor for schizophrenia: a Danish population-based cohort study. British Journal of Psychiatry 182, 117–122.CrossRefGoogle ScholarPubMed
Cantor-Graae, E, Selten, JP (2005). Schizophrenia and migration: a meta-analysis and review. American Journal of Psychiatry 162, 12–24.CrossRefGoogle ScholarPubMed
Cantor-Graae, E, Zolkowska, K, McNeil, TF (2005). Increased risk of psychotic disorder among immigrants in Malmo: a 3-year first-contact study. Psychological Medicine 35, 1155–1163.CrossRefGoogle ScholarPubMed
Castle, D, Wessely, S, Der, G, Murray, RM (1991). The incidence of operationally defined schizophrenia in Camberwell, 1965–84. British Journal of Psychiatry 159, 790–794.CrossRefGoogle ScholarPubMed
Cochrane, R (1977). Mental illness in immigrants to England and Wales: an analysis of mental hospital admissions, 1971. Social Psychiatry 12, 25–35.CrossRefGoogle Scholar
Cochrane, R, Bal, SS (1987). Migration and schizophrenia: an examination of five hypotheses. Social Psychiatry 22, 181–191.CrossRefGoogle ScholarPubMed
Coid, JW, Kirkbride, JB, Barker, D, Cowden, F, Stamps, R, Yang, M, Jones, PB (2008). Raised incidence rates of all psychoses among migrant groups: findings from the East London first episode psychosis study. Archives of General Psychiatry 65, 1250–1258.CrossRefGoogle ScholarPubMed
Cooper, HM, Hedges, LV, Valentine, JC (2009). The Handbook of Research Synthesis and Meta-Analysis, 2nd edn. Russell Sage Foundation: New York.Google Scholar
Corcoran, C, Perrin, M, Harlap, S, Deutsch, L, Fennig, S, Manor, O, Nahon, D, Kimhy, D, Malaspina, D, Susser, E (2008). Incidence of schizophrenia among second-generation immigrants in the Jerusalem perinatal cohort. Schizophrenia Bulletin, 35, 596–602.CrossRefGoogle ScholarPubMed
Dealberto, MJ (2007). Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both? Medical Hypotheses 68, 259–267.CrossRefGoogle ScholarPubMed
Dean, G, Walsh, D, Downing, H, Shelley, E (1981). First admissions of native-born and immigrants to psychiatric hospitals in South-East England 1976. British Journal of Psychiatry 139, 506–512.CrossRefGoogle ScholarPubMed
Egger, M, Smith, GD, Altman, DG (2001). Systematic Reviews in Health Care. Meta-analysis in Context. BMJ Books: London.CrossRefGoogle Scholar
Fearon, P, Kirkbride, JB, Morgan, C, Dazzan, P, Morgan, K, Lloyd, T, Hutchinson, G, Tarrant, J, Fung, WLA, Holloway, J, Mallett, R, Harrison, G, Leff, J, Jones, PB, Murray, RM (2006). Incidence of schizophrenia and other psychoses in ethnic minority groups: results from the MRC AESOP study. Psychological Medicine 36, 1541–1550.CrossRefGoogle ScholarPubMed
Fearon, P, Morgan, C (2006). Environmental factors in schizophrenia: the role of migrant studies. Schizophrenia Bulletin 32, 405–408.CrossRefGoogle ScholarPubMed
Gale, CR, Martyn, CN (1995). Migrant studies in multiple sclerosis. Progress in Neurobiology 47, 425–448.CrossRefGoogle ScholarPubMed
Harrison, G, Glazebrook, C, Brewin, J, Cantwell, R, Dalkin, T, Fox, R, Jones, P, Medley, I (1997). Increased incidence of psychotic disorders in migrants from the Caribbean to the United Kingdom. Psychological Medicine 27, 799–806.CrossRefGoogle ScholarPubMed
Harrison, G, Owens, D, Holton, A, Neilson, D, Boot, D (1988). A prospective study of severe mental disorder in Afro-Caribbean patients. Psychological Medicine 18, 643–657.CrossRefGoogle ScholarPubMed
Hitch, PJ, Clegg, P (1980). Modes of referral of overseas immigrant and native-born first admissions to psychiatric hospital. Social Science and Medicine. Medical Psychology and Medical Sociology 14A, 369–374.Google ScholarPubMed
Jablensky, A, Sartorius, N, Ernberg, G (1992). Schizophrenia: manifestations, incidence and course in different cultures. A World Health Organization ten-country study. Psychological Medicine. Monograph Supplement 20, 1–97.CrossRefGoogle ScholarPubMed
Janssen, I, Hanssen, M, Bak, M (2003). Discrimination and delusional ideation. British Journal of Psychiatry 182, 71–76.CrossRefGoogle ScholarPubMed
Kirkbride, JB, Fearon, P, Morgan, C, Dazzan, P, Morgan, K, Murray, RM, Jones, PB (2007). Neighbourhood variation in the incidence of psychotic disorders in Southeast London. Social Psychiatry and Psychiatric Epidemiology 42, 438–445.CrossRefGoogle ScholarPubMed
Krupinski, J, Cochrane, R (1980). Migration and mental health – a comparative study. Journal of Intercultural Studies 1, 49–57.CrossRefGoogle Scholar
Leao, TS, Sundquist, J, Frank, G, Johansson, LM, Johansson, SE, Sundquist, K (2006). Incidence of schizophrenia or other psychoses in first- and second-generation immigrants: a National Cohort Study. Journal of Nervous and Mental Disease 194, 27–33.CrossRefGoogle ScholarPubMed
Lin, SS, Kelsey, JL (2000). Use of race and ethnicity in epidemiologic research: concepts, methodological issues, and suggestions for research. Epidemiologic Reviews 22, 187–202.CrossRefGoogle ScholarPubMed
McGrath, J (1999). Hypothesis: is low prenatal vitamin D a risk-modifying factor for schizophrenia? Schizophrenia Research 40, 173–177.CrossRefGoogle ScholarPubMed
McGrath, J, Saha, S, Welham, J, El Saadi, O, MacCauley, C, Chant, D (2004). A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology. BMC Medicine 2, 13.CrossRefGoogle ScholarPubMed
Ödegaard, O (1932). Emigration and insanity. Acta Psychiatrica et Neurologica. Supplementum 4, 1–206.Google Scholar
Pai, M, McCulloch, M, Gorman, JD, Pai, N, Enanoria, W, Kennedy, G, Tharyan, P, Colford, JM Jr. (2004). Systematic reviews and meta-analyses: an illustrated, step-by-step guide. The National Medical Journal of India 17, 86–95.Google ScholarPubMed
Ramagopalan, SV, Dyment, DA, Ebers, GC (2008). Genetic epidemiology: the use of old and new tools for multiple sclerosis. Trends in Neurosciences 31, 645–652.CrossRefGoogle ScholarPubMed
Rwegellera, GG (1977). Psychiatric morbidity among West Africans and West Indians living in London. Psychological Medicine 7, 317–329.CrossRefGoogle Scholar
Sashidharan, SP (1993). Afro-Caribbeans and schizophrenia: the ethnic vulnerability hypothesis re-examined. International Review of Psychiatry 5, 129–143.CrossRefGoogle Scholar
Selten, JP, Cantor-Graae, E (2005). Social defeat: risk factor for schizophrenia? British Journal of Psychiatry 187, 101–102.CrossRefGoogle ScholarPubMed
Selten, JP, Cantor-Graae, E (2007). Hypothesis: social defeat is a risk factor for schizophrenia? British Journal of Psychiatry 191, s9–s12.CrossRefGoogle Scholar
Selten, JP, Cantor-Graae, E, Kahn, RS (2007). Migration and schizophrenia. Current Opinion in Psychiatry 20, 111–115.CrossRefGoogle ScholarPubMed
Selten, JP, Sijben, N (1994). First admission rates for schizophrenia in immigrants to the Netherlands: the Dutch national register. Social Psychiatry and Psychiatric Epidemiology 29, 71–77.CrossRefGoogle Scholar
Selten, JP, Slaets, JPJ, Kahn, RS (1997). Schizophrenia in Surinamese and Dutch Antillean immigrants to The Netherlands: evidence of an increased incidence. Psychological Medicine 27, 807–811.CrossRefGoogle Scholar
Sharpley, M, Hutchinson, G, McKenzie, K, Murray, RM (2001). Understanding the excess of psychosis among the African-Caribbean population in England. British Journal of Psychiatry 178, s60–s68.CrossRefGoogle Scholar
Smith, GN, Boydell, J, Murray, RM, Flynn, S, McKay, K, Sherwood, M, Honer, WG (2006). The incidence of schizophrenia in European immigrants to Canada. Schizophrenia Research 87, 205–211.CrossRefGoogle ScholarPubMed
Song, F, Sheldon, TA, Sutton, AJ, Abrams, KR, Jones, DR (2001). Methods for exploring heterogeneity in meta-analysis. Evaluation and the Health Professions 24, 126–151.CrossRefGoogle ScholarPubMed
Statistics Canada (2008). Visible minority population and population group reference guide, 2006 census. (http://www12.statcan.gc.ca/census-recensement/2006/ref/rp-guides/visible_minorityminorites_visibles-eng.cfm). Statistics Canada.Google Scholar
Stroup, DF, Berlin, JA, Morton, SC, Olkin, I, Williamson, GD, Rennie, D, Moher, D, Becker, BJ, Sipe, TA, Thacker, SB (2000). Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. Journal of the American Medical Association 283, 2008–2012.CrossRefGoogle ScholarPubMed
Tandon, R, Keshavan, MS, Nasrallah, HA (2008). Schizophrenia, ‘just the facts’ what we know in 2008. 2. Epidemiology and etiology. Schizophrenia Research 102, 1–18.CrossRefGoogle ScholarPubMed
Thomas, CS, Stone, K, Osborn, M, Thomas, PF, Fisher, M (1993). Psychiatric morbidity and compulsory admission among UK-born Europeans, Afro-Caribbeans and Asians in central Manchester. British Journal of Psychiatry 163, 91–99.CrossRefGoogle ScholarPubMed
Torrey, EF, Bartko, JJ, Lun, Z-R, Yolken, RH (2007). Antibodies to toxoplasma gondii in patients with schizophrenia: a meta-analysis. Schizophrenia Bulletin 33, 729–736.CrossRefGoogle ScholarPubMed
Van Os, J, Castle, DJ, Takei, N, Der, G, Murray, RM (1996). Psychotic illness in ethnic minorities: clarification from the 1991 census. Psychological Medicine 26, 203–208.CrossRefGoogle ScholarPubMed
Veen, N, Selten, JP, Hoek, HW, Feller, W, van der Graaf, Y, Kahn, R (2002). Use of illicit substances in a psychosis incidence cohort: a comparison among different ethnic groups in the Netherlands. Acta Psychiatrica Scandinavica 105, 440–443.CrossRefGoogle Scholar
Veling, W, Hoek, HW, Mackenbach, JP (2008 a). Perceived discrimination and the risk of schizophrenia in ethnic minorities. Social Psychiatry and Psychiatric Epidemiology 43, 953–959.CrossRefGoogle ScholarPubMed
Veling, W, Selten, JP, Veen, N, Laan, W, Blom, JD, Hoek, HW (2006). Incidence of schizophrenia among ethnic minorities in the Netherlands: a four-year first-contact study. Schizophrenia Research 86, 189–193.CrossRefGoogle ScholarPubMed
Veling, W, Susser, E, van Os, J, Mackenbach, JP, Selten, JP, Hoek, HW (2008 b). Ethnic density of neighborhoods and incidence of psychotic disorders among immigrants. American Journal of Psychiatry 165, 66–73.CrossRefGoogle ScholarPubMed
Weiser, M, Werbeloff, N, Vishna, T, Yoffe, R, Lubin, G, Shmushkevitch, M, Davidson, M (2008). Elaboration on immigration and risk for schizophrenia. Psychological Medicine 38, 1113–1119.CrossRefGoogle ScholarPubMed
Zolkowska, K, Cantor-Graae, E, McNeil, TF (2001). Increased rates of psychosis among immigrants to Sweden: is migration a risk factor for psychosis? Psychological Medicine 31, 669–678.CrossRefGoogle ScholarPubMed