Diabetes Mellitus and Impaired Glucose Tolerance in Patients with Schizophrenia

OBJECTIVES: This study aimed to establish the prevalence of diabetes mellitus (DM) and impaired glucose tolerance in patients with schizophrenia and to elucidate some of the factors associated with hyperglycemia. METHODS: We studied a sample of 194 patients with schizophrenia. We determined fasting blood glucose and insulin levels at the start of the testing period; patients were given an oral glucose tolerance test after an overnight fast. RESULTS: The overall prevalence of diabetes and impaired glucose tolerance in these patients was 16.0% and 30.9%, respectively. These rates were higher than those reported in the general population. Patients with disordered glucose homeostasis were significantly older (P = 0.005, Kruskal-Wallis test). There was no significant effect of sex or ethnicity on diabetes. CONCLUSIONS: Our findings suggest that patients with schizophrenia are more vulnerable to developing DM. We caution clinicians to be mindful of the increased risk and to be vigilant for such a development.