Quetiapine and Long-Term Weight Change

BACKGROUND: To assess the magnitude and pattern of weight change during long-term treatment with the atypical antipsychotic quetiapine. METHOD: Data were collected from patients with a DSM-IV diagnosis of schizophrenia treated with quetiapine in the AstraZeneca clinical trials program from July 1993 to May 1999. Weight changes in patients treated for 12, 52, and 104 weeks were analyzed; the primary parameter was the change in weight at week 52. RESULTS: In total, 352 patients were treated with quetiapine for 52 weeks. The mean weight gain at this timepoint was 3.19 kg; median weight gain was 2.5 kg. Overall, 37% of patients gained >or= 7% of their baseline body weight; however, the degree of weight gain was inversely related to baseline body mass index in this cohort. In patients treated with < 200 mg/day of quetiapine, mean weight gain was 1.54 kg, compared with 4.08 kg for 200 to 399 mg/day, 1.89 kg for 400 to 599 mg/day, and 3.57 kg for >or= 600 mg/day; median weight gain was 0.95 kg, 3.40 kg, 2.00 kg, and 3.34 kg, respectively. Analysis of longitudinal weight changes indicated that most weight gain (> 60%) occurred within the first 12 weeks of quetiapine treatment, with modest changes after 6 months. CONCLUSIONS: Long-term treatment with quetiapine monotherapy is associated with moderate weight gain. Most weight gain occurs within the first 12 weeks of treatment and has no clear dose relationship.