Objective: This study examined the main metabolic side effects induced by antipsychotic treatment in a cohort of first episode drug-naïve subjects after the first year of treatment.
Methods: A randomized, open-label, prospective clinical trial was conducted. Participants were 164 consecutive subjects included in a first episode program and never treated with antipsychotic medication. Patients were assigned to haloperidol, olanzapine or risperidone. The main outcome measures were changes at 1 year in fasting glucose parameters (glucose, insulin levels and insulin resistance index) and changes in fasting lipid parameters (total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol).
Results: 144 of the total sample were evaluated at 1 year. There was a statistically significant increase in the mean values of insulin levels, insulin resistance index, total cholesterol, LDL-cholesterol and triglycerides. No pathological values in fasting glucose plasma levels were found at baseline and there were no changes after 1 year. Weight gain was positively correlated with changes in insulin levels, insulin resistance index and triglyceride levels. We did not detect statistically significant differences between treatments in any of the parameters evaluated.
Conclusions: Fasting glycaemia and insulin concentrations at baseline do not support the hypothesis that schizophrenia is associated with an underlying abnormality in glucose metabolism. The changes in insulin and lipid parameters at 1 year seem to be related to the magnitude of weight gain. There were no significant differences between haloperidol, olanzapine and risperidone concerning metabolic adverse effects after the first year of treatment.