Background: Some studies suggest individuals with schizophrenia have an increased risk of diabetes prior to antipsychotic use. Small sample sizes and the potential for confounding by hypercortisolaemia have decreased confidence in those results.
Aims: To examine diabetes-related factors in newly diagnosed, antipsychotic-naive people with non-affective psychosis.
Method: Participants with psychosis (the psychosis group; n = 50) and matched controls (the control group; n = 50) were given a 2 h oral glucose tolerance test. Fasting concentrations were also determined for adiponectin, interleukin-6 and C-reactive protein.
Results: Compared with the control group, the psychosis group had significant increases in 2 h glucose and interleukin-6 concentrations, and in the prevalence of abnormal glucose tolerance (16% of psychosis group v. 0% of control group). Adiponectin and C-reactive protein concentrations did not differ significantly between the two groups. These findings could not be attributed to differences in cortisol concentrations, smoking, gender, neighbourhood of residence, body mass index, aerobic conditioning, ethnicity, socioeconomic status or age.
Conclusions: Individuals with non-affective psychosis appear to have an increased prevalence of abnormal glucose tolerance prior to antipsychotic treatment, as well as abnormalities in a related inflammatory molecule. These underlying problems may contribute to the metabolic side-effects of antipsychotic medications.