Metabolic Effects of Olanzapine in Newly-Diagnosed, Antipsychotic-Naïve Patients With Nonaffective Psychosis

Brian J. Miller, MD, MPH; Emilio Fernandez-Egea, MD; Clemente Garcia-Rizo, MD; Miguel Bernardo, MD, PhD; and Brian Kirkpatrick, MD
Department of Psychiatry, Medical College of Georgia, Augusta (Drs Kirkpatrick and Miller); Department of Psychiatry, University of Cambridge, United Kingdom (Dr Fernandez-Egea); and the Department de Psiquiatria, Universitat de Barcelona, Barcelona, Spain (Drs Bernardo and Garcia-Rizo)

This abstract presentation was supported by the National Institute of Diabetes and Digestive and Kidney Diseases.

Introduction: Antipsychotic medications are associated with an increased risk of diabetes. Previous studies have also found an increased risk of type 2 diabetes in the relatives of schizophrenia probands. We explored the metabolic side effects of olanzapine in newly-diagnosed, antipsychotic-naïve patients with nonaffective psychosis.

Methods: Thirty-one newly-diagnosed, antipsychotic-naïve patients with nonaffective psychosis were enrolled in a 16-week open trial of olanzapine. Fasting glucose, fasting insulin, and body mass index were measured at baseline and at 4-week intervals.

Results: There was a significant, linear increase over time in fasting glucose (p=0.004) and body mass index (p=0.001), but not fasting insulin (p=0.614). A parental history of type 2 diabetes was associated with a significantly higher body mass index than found in patients without such a history, and this difference was sustained throughout the trial. Parental history of type 2 diabetes was also associated with a greater rate of increase in BMI at the trend level (p=0.074). Neither the pro-inflammatory molecule interleukin-6 nor baseline fasting glucose concentration predicted changes in these metabolic measures.

Conclusions: Changes in metabolic measures with olanzapine treatment can be detected very early in treatment. The absence of a change in fasting insulin suggests a failure of the pancreatic islet cell to compensate for the increase in fasting glucose. Parental history of type 2 diabetes may predict side effects through its association with a higher body mass index, but larger studies are needed to identify patients who may be particularly vulnerable to the metabolic side effects of antipsychotics.

References
Fernandez-Egea E, Miller B, Bernardo M, et al. Parental history of type 2 diabetes in patients with nonaffective psychosis. Schizophr Res. 2008;98(1–3):302–306.

Fernandez-Egea E, Bernardo M, Donner T, et al. The metabolic profile of antipsychotic-naïve individuals with nonaffective psychosis. Br J Psychiatry. 2009;194(5):434–438.

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