Prevalence of diabetes and impaired glucose tolerance in patients with schizophrenia

Background A number of studies have examined the prevalence of diabetes mellitus and impaired glucose tolerance in general populations and in those with schizophrenia and other forms of serious mental illness. Aims To establish whether it is possible to describe accurately comparative rates of diabetes mellitus and impaired glucose tolerance in populations of people with schizophrenia and those without mental illness. Method Review of current literature Results Research published in the preneuroleptic era suggested that people with severe mental illness were at increased risk of developing glycaemic abnormalities. Recent studies appear to confirm that the prevalence of diabetes and impaired glucose tolerance may be higher in people with schizophrenia than in the general population, and suggest that patients with schizophrenia have impaired glucose tolerance even before they begin treatment. Conclusions Schizophrenia may be a significant and independent risk factor for both diabetes and impaired glucose tolerance. Current data preclude precise estimates of the prevalence of these conditions among people with schizophrenia. Declaration of interest C.B. is an employee of Eli Lilly Co; R.H. has received educational grants and fees for lecturing and consultancy work from Eli Lilly Co.