A cross-sectional evaluation of adiponectin plasma levels in patients with schizophrenia and schizoaffective disorder.

BACKGROUND: In recent years, several studies showed increased rates of hyperglycaemia, diabetes, dyslipidemia, metabolic syndrome as well as cardiovascular disease in schizophrenic patients. The underlying mechanism, however, is poorly understood. Adiponectin is a recently identified adipocyte-derived protein, with low adiponectin levels being associated with metabolic abnormalities such as obesity, insulin resistance and type 2 diabetes. METHODS: Fasting adiponectin levels were assessed in a cross-sectional sample of 386 patients with schizophrenia or schizoaffective disorder. All patients were on monotherapy of second-generation antipsychotics (SGA) and underwent an extensive metabolic screening including an oral glucose tolerance test (OGTT). RESULTS: Adiponectin plasma levels were inversely correlated with BMI, and differed significantly between patients with normal weight, overweight or obesity (p<0.05). Patients who met criteria for the metabolic syndrome, according to adapted National Cholesterol Educational Program - Adult Treatment Panel criteria (NCEP-ATP III) (29.3%), had significantly lower adiponectin levels than patients not meeting metabolic syndrome criteria (p<0.0001). Patients without glucose abnormalities (78%) had significantly higher adiponectin levels than patients with diabetes (5.7%) (p<0.05). After controlling for components of metabolic syndrome and sex, antipsychotic medication independently influenced adiponectin levels (p<0.0001), with the lowest mean levels in patients on clozapine and olanzapine. CONCLUSIONS: Adiponectin levels in schizophrenic patients mirror what is observed in the general population, with the lowest levels in the most metabolically comprised subjects. However, antipsychotic medication may also influence adiponectin regulation independently, a finding that should be confirmed in longitudinal studies.