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

Acta Psychiatr Scand. 2008 May;117(5):342-7. doi: 10.1111/j.1600-0447.2008.01158.x. Epub 2008 Feb 26.


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-naïve 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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antipsychotic Agents / administration & dosage
  • Antipsychotic Agents / adverse effects*
  • Benzodiazepines / administration & dosage
  • Benzodiazepines / adverse effects*
  • Diabetes Mellitus / epidemiology*
  • Diabetes Mellitus / etiology*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Glucose Intolerance
  • Haloperidol / administration & dosage
  • Haloperidol / adverse effects*
  • Humans
  • Male
  • Olanzapine
  • Prospective Studies
  • Schizophrenia / drug therapy*
  • Schizophrenia / epidemiology*


  • Antipsychotic Agents
  • Benzodiazepines
  • Haloperidol
  • Olanzapine