Psychoses, ethnicity and socio-economic status

Kirkbride, J. B. PhD
Barker, D. MRCPsych
Cowden, F. MRCPsych
Stamps, R. MRCPsych
Yang, M. MD, MPh
Jones, P. B. PhD
Coid, J. W. MD

J. B. Kirkbride, PhD, University Department of Psychiatry, Addenbrooke's Hospital, Cambridge, UK; D. Barker, MRCPsych, F. Cowden, MRCPsych, R. Stamps, MRCPsych, M. Yang, MD, MPh, Forensic Psychiatry Research Unit, Queen Mary College School of Medicine, University of London, UK; P. B. Jones, PhD, University Department of Psychiatry, Addenbrooke's Hospital, Cambridge, UK; J. W. Coid, MD, Forensic Psychiatry Research Unit, Queen Mary College School of Medicine, University of London, UK.

Correspondence: J. B. Kirkbride, Box 189, University Department of Psychiatry, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK. Email: [email protected]

Declaration of interest: None. Funding detailed in Acknowledgements.

(First received 14 June 2007, final revision 25 January 2008, accepted 4 February 2008)

British Journal of Psychiatry 193(1):p 18-24, July 2008.

Background

Consistent observation of raised rates of psychoses among Black and minority ethnic (BME) groups may possibly be explained by their lower socio-economic status.

Aims

To test whether risk for psychoses remained elevated in BME populations compared with the White British, after adjustment for age, gender and current socio-economic status.

Method

Population-based study of first-episode DSM–IV psychotic disorders, in individuals aged 18–64 years, in East London over 2 years.

Results

All BME groups had elevated rates of a psychotic disorder after adjustment for age, gender and socio-economic status. For schizophrenia, risk was elevated for people of Black Caribbean (incidence rate ratios (IRR)=3.1, 95% CI 2.1–4.5) and Black African (IRR=2.6, 95% CI 1.8–3.8) origin, and for Pakistani (IRR=3.1, 95% CI 1.2–8.1) and Bangladeshi (IRR=2.3, 95% CI 1.1–4.7) women. Mixed White and Black Caribbean (IRR=7.7, 95% CI 3.2–18.8) and White Other (IRR=2.1, 95% CI 1.2–3.8) groups had elevated rates of affective psychoses (and other non-affective psychoses).

Conclusions

Elevated rates of psychoses in BME groups could not be explained by socio-economic status, even though current socio-economic status may have overestimated the effect of this confounder given potential misclassification as a result of downward social drift in the prodromal phase of psychosis. Our findings extended to all BME groups and psychotic disorders, though heterogeneity remains.