Skip to main content Accessibility help
×
×
Home

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

  • F. Bourque (a1), E. van der Ven (a1) and A. Malla (a1)

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.

Copyright

Corresponding author

*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)

References

Hide All
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. 219290. American Psychiatric Association: Washington, DC.
Bebbington, PE, Hurry, J, Tennant, C (1981). Psychiatric disorders in selected immigrant groups in Camberwell. Social Psychiatry 16, 4351.
Bhui, K, Tsangarides, N (2008). Culture and schizophrenia. Psychiatry 7, 454457.
Borenstein, M (2010). Meta-Analysis: Computing Treatment Effects and Effect Sizes. Wiley: Chichester.
Borenstein, M, Hedges, LV, Higgins, JPT (2005). Comprehensive Meta-analysis Version 2. Biostat: Englewood, NJ.
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. 3340. Wiley: Chichester.
Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR (2009 b). Fixed-effect versus random-effects models. In Introduction to Meta-Analysis, pp. 7786. Wiley: Chichester.
Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR (2009 c). Identifying and quantifying heterogeneity. In Introduction to Meta-Analysis, pp. 107126. Wiley: Chichester.
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, 13361338.
Cantor-Graae, E (2007). The contribution of social factors to the development of schizophrenia: a review of recent findings. Canadian Journal of Psychiatry 52, 277286.
Cantor-Graae, E, Pedersen, CB (2007). Risk of schizophrenia in second-generation immigrants: a Danish population-based cohort study. Psychological Medicine 37, 485494.
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, 117122.
Cantor-Graae, E, Selten, JP (2005). Schizophrenia and migration: a meta-analysis and review. American Journal of Psychiatry 162, 1224.
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, 11551163.
Castle, D, Wessely, S, Der, G, Murray, RM (1991). The incidence of operationally defined schizophrenia in Camberwell, 1965–84. British Journal of Psychiatry 159, 790794.
Cochrane, R (1977). Mental illness in immigrants to England and Wales: an analysis of mental hospital admissions, 1971. Social Psychiatry 12, 2535.
Cochrane, R, Bal, SS (1987). Migration and schizophrenia: an examination of five hypotheses. Social Psychiatry 22, 181191.
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, 12501258.
Cooper, HM, Hedges, LV, Valentine, JC (2009). The Handbook of Research Synthesis and Meta-Analysis, 2nd edn. Russell Sage Foundation: New York.
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, 596602.
Dealberto, MJ (2007). Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both? Medical Hypotheses 68, 259267.
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, 506512.
Egger, M, Smith, GD, Altman, DG (2001). Systematic Reviews in Health Care. Meta-analysis in Context. BMJ Books: London.
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, 15411550.
Fearon, P, Morgan, C (2006). Environmental factors in schizophrenia: the role of migrant studies. Schizophrenia Bulletin 32, 405408.
Gale, CR, Martyn, CN (1995). Migrant studies in multiple sclerosis. Progress in Neurobiology 47, 425448.
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, 799806.
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, 643657.
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, 369374.
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, 197.
Janssen, I, Hanssen, M, Bak, M (2003). Discrimination and delusional ideation. British Journal of Psychiatry 182, 7176.
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, 438445.
Krupinski, J, Cochrane, R (1980). Migration and mental health – a comparative study. Journal of Intercultural Studies 1, 4957.
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, 2733.
Lin, SS, Kelsey, JL (2000). Use of race and ethnicity in epidemiologic research: concepts, methodological issues, and suggestions for research. Epidemiologic Reviews 22, 187202.
McGrath, J (1999). Hypothesis: is low prenatal vitamin D a risk-modifying factor for schizophrenia? Schizophrenia Research 40, 173177.
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.
Ödegaard, O (1932). Emigration and insanity. Acta Psychiatrica et Neurologica. Supplementum 4, 1206.
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, 8695.
Ramagopalan, SV, Dyment, DA, Ebers, GC (2008). Genetic epidemiology: the use of old and new tools for multiple sclerosis. Trends in Neurosciences 31, 645652.
Rwegellera, GG (1977). Psychiatric morbidity among West Africans and West Indians living in London. Psychological Medicine 7, 317329.
Sashidharan, SP (1993). Afro-Caribbeans and schizophrenia: the ethnic vulnerability hypothesis re-examined. International Review of Psychiatry 5, 129143.
Selten, JP, Cantor-Graae, E (2005). Social defeat: risk factor for schizophrenia? British Journal of Psychiatry 187, 101102.
Selten, JP, Cantor-Graae, E (2007). Hypothesis: social defeat is a risk factor for schizophrenia? British Journal of Psychiatry 191, s9–s12.
Selten, JP, Cantor-Graae, E, Kahn, RS (2007). Migration and schizophrenia. Current Opinion in Psychiatry 20, 111115.
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, 7177.
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, 807811.
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, s60s68.
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, 205211.
Song, F, Sheldon, TA, Sutton, AJ, Abrams, KR, Jones, DR (2001). Methods for exploring heterogeneity in meta-analysis. Evaluation and the Health Professions 24, 126151.
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.
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, 20082012.
Tandon, R, Keshavan, MS, Nasrallah, HA (2008). Schizophrenia, ‘just the facts’ what we know in 2008. 2. Epidemiology and etiology. Schizophrenia Research 102, 118.
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, 9199.
Torrey, EF, Bartko, JJ, Lun, Z-R, Yolken, RH (2007). Antibodies to toxoplasma gondii in patients with schizophrenia: a meta-analysis. Schizophrenia Bulletin 33, 729736.
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, 203208.
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, 440443.
Veling, W, Hoek, HW, Mackenbach, JP (2008 a). Perceived discrimination and the risk of schizophrenia in ethnic minorities. Social Psychiatry and Psychiatric Epidemiology 43, 953959.
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, 189193.
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, 6673.
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, 11131119.
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, 669678.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Psychological Medicine
  • ISSN: 0033-2917
  • EISSN: 1469-8978
  • URL: /core/journals/psychological-medicine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed