Weight gain with add‐on second‐generation antipsychotics in bipolar disorder: a naturalistic study

OBJECTIVE: Our aim was to investigate the prevalence and magnitude of weight gain in-patients with bipolar disorder when treated with a second-generation antipsychotic as an add-on treatment to a mood stabilizer in routine clinical practice. METHODS: Data were derived from the quality register for bipolar disorder in Sweden (BipoläR). Patients with bipolar disorder who started add-on treatment with a SGA (n = 575) were compared at next yearly follow-up with age and sex matched patients who were only treated with a mood stabilizer (n = 566). The primary outcome measure was change in body weight and body mass index (BMI). We also assessed the prevalence of clinically significant weight gain defined as ≥7% gain in body weight. RESULTS: The group that received add-on treatment with antipsychotics neither gained more weight nor were at higher risk for a clinically significant weight gain than the reference group. Instead, factors associated with clinically significant weight gain were female sex, young age, low-baseline BMI, and occurrence of manic/hypomanic episodes. CONCLUSION: We found no evidence of an overall increased risk of weight gain for patients with bipolar disorder after receiving add-on SGA to a mood stabilizer in a routine clinical setting.