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Glucose Tolerance and Diabetes Risk in Schizophrenic Patients

Feb 13, 2015

Due to the metabolic effects of antipsychotic medications, glucose control is very important in diabetic patients with schizophrenia…

Prior studies have shown that patients with schizophrenia can have higher rates of impaired glucose tolerance, insulin resistance, and increased risk for type 2 diabetes mellitus. Risk for diabetes in schizophrenic patients is two-fold over those in the general population.

Both typical and atypical antipsychotics have been associated with an increase in diabetes mellitus risk factors. Older and newer antipsychotics can lead to hyperglycemia and worsen existing or new-onset type II diabetes.

In this study patients diagnosed with schizophrenia were observed between April 2011 and September 2012. Baseline Oral Glucose Tolerance Test (OGTT) was done to test glucose dysregulation in (drug naive) antipsychotic treatment group, before and after starting them on one of four antipsychotics. Baseline OGTT was also completed in a healthy control group before and after.

The four antipsychotics in the study randomly assigned were, Aripiprazole, Risperidone, Haloperidol and Olanzapine were the four treatment groups. ANOVA was used to compare fasting and 2 hour post load plasma glucose levels across follow-up times. A P < 0.005 was taken as significant.

The fasting plasma glucose and post load plasma glucose levels (2hrs) of the schizophrenia treatment group and the healthy control group seemed to have a trend in glucose dysregulation for the first 6 weeks. After week 14 the outlier that was significantly different from the other three treatment groups and the most glucose dysregulation was Olanzapine. P < 0.001 in fasting plasma glucose and plasma glucose (2hrs) at 14 weeks.

Certain antipsychotic medications can still be of benefit in type II diabetes or patients with diabetes mellitus risk if properly monitored and life style modifications are included. Depending on patient history and other factors, one antipsychotic may be more beneficial than the other based on clinical judgment.

Practice Pearls:

  • Aripiprazole and risperidone had the lowest incidence of glucose dysregulation in this study.
  • The schizophrenia patients (treatment group) in this study did not show a statistically significant elevation in plasma glucose when compared to the healthy control group.
  • If Olanzapine is needed to be started as an initial treatment option, another antipsychotic can be started later on and metabolic panels should be monitored regularly throughout the entire treatment.

Wani, Rayees Ahmad et al. “Diabetes Mellitus and Impaired Glucose Tolerance in Patients with Schizophrenia, before and after Antipsychotic Treatment.” Journal of Neurosciences in Rural Practice 6.1 (2015): 17–22. PMC. Web. 4 Feb. 2015.