Diabetes and schizophrenia - effect of disease or drug? Results from a randomized, double-blind, controlled prospective study in first-episode schizophrenia

Objective: There have been innumerable advances in the pharmacotherapy of schizophrenia, but problems have emerged hand-in-glove, such as the presence of treatment-emergent glucose intolerance and frank diabetes mellitus (DM). Method: Medication-naive patients with schizophrenia (n = 99) underwent baseline fasting and 2 h post-prandial plasma glucose measurements repeated after 6 weeks after randomization to receive olanzapine, risperidone or haloperidol. The results were compared with a matched healthy control group. Results: A significant difference (P = 0.002) in baseline 2 h post-prandial blood sugar (PPBS) was noted between the control group and the treatment group along with a significant increase in weight (P < 0.001), fasting blood sugar (P = 0.01) and 2 h PPBS (P < 0.001) from baseline to endpoint between the groups. A statistical significance in the incidence of DM at endpoint by the WHO criteria (10.1%) was also noted. Conclusion: Male patients with schizophrenia are liable to develop DM. Antipsychotic treatment leads to the development of DM in a significant 10.1% within 6 weeks.