Aims: Second-generation antipsychotics (SGA), especially clozapine and olanzapine, are associated with increased metabolic risk. Plasma adiponectin levels, vary in schizophrenia patients as in the general population according to gender, adiposity and metabolic syndrome (MetS).
Here, we investigated whether different SGAs differentially influence plasma adiponectin levels independent of body mass index (BMI) and MetS status.
Methods: One hundred and thirteen schizophrenia patients (65.5% males) who were free of antipsychotic medication were enrolled in this open-label prospective single-centre study and received either risperidone (n=54) or olanzapine (n=59). They were followed-up for 12 weeks. Average daily dose was 4.35 mg/day for risperidone and 17.36 mg/day for olanzapine. Plasma adiponectin levels as well as fasting metabolic parameters were measured at baseline, 6 and 12 weeks.
Results: Baseline BMI (23.7 vs 23.2 kg/m2), mean fasting plasma glucose (FPG) (mean fasting plasma insulin (11.3 vs 12.0 mIU/ml) and mean plasma adiponectin levels (10 154 vs 11 280 ng/ml) were similar in the risperidone group and in the olanzapine group. A significant increase in body weight occurred over time in the olanzapine group as opposed to a numerical increase in the risperidone group (+7.0 kg vs +3.1 kg, P<0.05). Changes in MetS prevalence, in glucose and insulin levels and in HOMA-IR were not significant.
We observed a significant (P=0.0002) treatment by time interaction showing an adiponectin increase in the risperidone-treated patients (from 10 154 to 11 124 ng/ml) but an adiponectin decrease in olanzapine-treated patients (from 11 280 to 8988 ng/ml). This effect was independent of BMI and the presence/absence of MetS.
Conclusion: The differential effect of antipsychotic treatment (risperidone versus olanzapine) on plasma adiponectin levels over time suggests a specific effect on adipose tissues, similar in humans to animal models. The observed specific olanzapine-associated reduction in plasma adiponectin levels may contribute to the increased metabolic risk with olanzapine compared to risperidone.