Impaired Fasting Glucose Tolerance in First-episode, Drug-naive Patients with Schizophrenia

Objective: This study examined the prevalence of impaired fasting glucose tolerance in first-episode, drug-naive patients with schizophrenia.

Method: In this cross-sectional study, fasting plasma levels of glucose, insulin, lipids, and cortisol were measured in 15 male and 11 female hospitalized Caucasian patients with DSM-IV schizophrenia (mean age=33.6 years) and age- and sex-matched healthy comparison subjects. The patients and comparison subjects were also matched in terms of various life-style and anthropometric measures.

Results: More than 15% of the drug-naive, first-episode patients with schizophrenia had impaired fasting glucose tolerance, compared to none of the healthy volunteers. Compared with the healthy subjects, the patients with schizophrenia had significantly higher fasting plasma levels of glucose (mean=88.2 mg/dl, SD=5.4, for the healthy subjects versus mean=95.8 mg/dl, SD=16.9, for the patients), insulin (mean=7.7 micro u/ml, SD=3.7, versus mean=9.8 micro u/ml, SD=3.9), and cortisol (mean=303.2 nmol/liter, SD=10.5, versus mean=499.4 nmol/liter, SD=161.4) and were more insulin resistant, as measured with homeostasis model assessment (mean=1.7, SD=0.7, for the healthy subjects versus mean=2.3, SD=1.0, for the patients).

Conclusions: First-episode, drug-naive patients with schizophrenia have impaired fasting glucose tolerance and are more insulin resistant and have higher levels of plasma glucose, insulin, and cortisol than healthy comparison subjects.