Equally increased risk for metabolic syndrome in patients with bipolar disorder and schizophrenia treated with second-generation antipsychotics

Objective: Although second-generation antipsychotics (SGAs) are widely used in treating schizophrenia and bipolar disorder, their effects on dyslipidemia, glucose intolerance, metabolic syndrome (MetS), and coronary heart disease (CHD) risk are less well documented for bipolar disorder. We compared bipolar disorder and schizophrenia patients receiving SGAs to determine whether MetS prevalence is influenced by the primary psychiatric diagnosis or concomitant mood stabilizer treatment. Methods: Admission assessment of MetS criteria (abdominal obesity, fasting hypertriglyceridemia, low high-density lipoprotein cholesterol, hyperglycemia, arterial hypertension) and the calculated 10-year CHD risk in bipolar disorder and schizophrenia patients treated with SGAs and closely matched for age, sex, and race. Results: Compared to schizophrenia patients (n = 111), those with bipolar disorder (n = 74) had lower body mass index (27.1 ± 5.3 versus 29.9 ± 8.1, p = 0.0053), were more likely treated with mood stabilizers (60.8 versus 36.0, p = 0.0009), and less likely treated with clozapine (1.3% versus 15.3%, p = 0.0017) or two antipsychotics (10.8% versus 34.2%, p = 0.0003). Despite these differences, bipolar disorder and schizophrenia patients had comparable rates of MetS (43.2% versus 45.9%, p = 0.71) and predicted CHD events (10-year risk >10%: 18.9% versus 23.4%, p = 0.47). Using ≥100 mg/dL as the adapted glucose criterion, MetS rates were 54.0% in both diagnostic groups (p = 1.0). Mood stabilizer co-treatment was not associated with MetS or its individual criteria. Conclusions: Patients with bipolar disorder and schizophrenia who are treated with SGAs have similarly high rates of MetS. These findings suggest a shared susceptibility to antipsychotic-related metabolic dysregulations that is not primarily related to psychiatric diagnosis or concomitant mood stabilizer treatment.