Background: This is the first study in bipolar patients, aimed to evaluate possible roles of the drugs, [atypical antipsychotics (AA) and mood stabilizers (MS)], inducing metabolic syndrome (MetS). Methods: 125 bipolar patients, diagnosed according to the DSM IV, were assessed cross-sectionally for MetS according to the National Cholesterol Educational Program criteria (NCEP ATP 111). Patients included in the study were required to receive medications (AAs: quetiapine, risperidone and olanzapine, and MSs: Lithium, Sodium Valproate, Carbamazepine, Lamotrigine) for at least 3 months. Patients are divided into three groups as only AA users, AA+MS users and only NIS users. Results: Of the patients, 32% were MetS, a proportion higher than normal population and similar as previous studies in bipolar patients. AA taking patients had significantly higher MetS rates than the others (chi(2) = 10.47 df=2 p=0.005). Also, AA taking patients had significantly higher MetS rates than NIS taking patients (chi(2) = 8.86 df = 1 p=0.003). There was no significant difference among quetiapine, olanzapine, risperidone usage for MetS prevalences (chi(2) = 0.38 df=2 p=0.92). Conclusions: AA taking bipolar patients had higher MetS rates. Despite already existing data on MetS and antipsychotics, this cross-sectional study is the first research, discusses AAs and MSs for inducing MetS in bipolar disorder. Prospectively designed researches should be conducted for further clarification of the role of these drugs in MetS. (c) 2006 Elsevier B.V. All rights reserved.