Prevalence and correlates of overweight in drug-naïve patients with bipolar disorder

BACKGROUND: Patients with bipolar disorder may be at greater risk for overweight and obesity than individuals in the general population. This risk may be due to the illness itself, to mediating factors (diet, life style) and/or to medications used to treat the disorder. This investigation explores the association between body weight and bipolar illness in drug-naïve patients. METHODS: Weight and height were retrospectively obtained from 76 clinical charts of drug-naïve patients with bipolar disorder (DSM-IV-TR). A reference group for comparison was then selected from another psychiatric population (65 patients with obsessive-compulsive disorder) and investigated with the same methodology to estimate their BMI. A second focus was to examine the differences in baseline demographic and clinical characteristics between overweight and non-overweight bipolar patients. RESULTS: A total of 40.8\% of the patients with bipolar disorder met criteria for obesity or overweight with significant difference in comparison with obsessive-compulsive patients (10.8\%). The highest proportions of depression at index episode were in the overweight group (83.3\%) with significant difference with the non-overweight patients (58.1\%). LIMITATIONS: Retrospective study. Weight measurement not in euthymic period. CONCLUSIONS: Overweight is significantly more prevalent in drug-naïve patients with bipolar disorder than in another drug-naïve psychiatric patients (OCD). In agreement with previous studies, the number of patients experiencing a depressive episode was significantly higher in the overweight than in the non-overweight group. These results suggest that the prevalence of overweight in bipolar patients is also influenced by the illness itself or mediating factors such as diet and life style than by pharmacologic treatment.