Email updates

Keep up to date with the latest news and content from BMC Psychiatry and BioMed Central.

Open Access Research article

The incidence and prevalence of diabetes in patients with serious mental illness in North West Wales: Two cohorts, 1875–1924 & 1994–2006 compared

Joanna Le Noury1, Afshan Khan1, Margaret Harris1, Winnie Wong1, Dawn Williams1, Tony Roberts1, Richard Tranter1 and David Healy2*

Author Affiliations

1 Department of Psychiatry, North West Wales NHS Trust, Bangor, Wales, LL57 2PW, UK

2 Department of Psychological Medicine, Cardiff University, Bangor, Wales, LL57 2PW, UK

For all author emails, please log on.

BMC Psychiatry 2008, 8:67  doi:10.1186/1471-244X-8-67

Published: 7 August 2008



Against a background of interest in rates of diabetes in schizophrenia and related psychoses and claims that data from historical periods demonstrate a link that antedates modern antipsychotics, we sought to establish the rate of diabetes in first onset psychosis and subsequent prevalence in historical and contemporary cohorts.


Analysis of two epidemiologically complete databases of individuals admitted for mental illness. 3170 individuals admitted to the North Wales Asylum between 1875–1924 and tracked over 18,486 patient years and 394 North West Wales first admissions for schizophrenia and related psychoses between 1994 and 2006 and tracked after treatment.


The prevalence of Type 2 diabetes among patients with psychoses at time of first admission in both historical and contemporary samples was 0%. The incidence of diabetes remained 0% in the historical sample throughout 15 years of follow-up but rose in the contemporary sample after 3, 5 and 6 years of treatment with an incidence rate double the expected population rate so that the 15 year prevalence is likely to be over 8%.


No association was found between diabetes and serious mental illness, but there may be an association between diabetes and treatment.