CASE REPORTWeight gain during long-term treatment with olanzapine: a case seriesHaberfellner, Egon Michaela; Rittmannsberger, HansbAuthor Information aPsychiatric Practice, Linz bLandesnervenklinik Wagner-Jauregg, Linz, Austria Correspondence and requests for reprints to Egon Michael Haberfellner, Psychiatric Practice, Hauptstrasse 83–85, A-4040 Linz, Austria Tel: +43 7327 36293; fax: +43 7327 16511 22; e-mail: [email protected] Received 19 May 2003 Accepted 19 November 2003 International Clinical Psychopharmacology: July 2004 - Volume 19 - Issue 4 - p 251-253 doi: 10.1097/01.yic.0000113105.67404.5f Buy Metrics Abstract The aim of this study was to assess the prevalence of weight gain during long-term treatment with olanzapine under routine conditions. Weight changes in a sample of 27 outpatients with schizophrenic or schizoaffective disorder were assessed over a mean duration of treatment of 22 months (6–42 months). Treatment with olanzapine was started anew or switched from a conventional antipsychotic drug. Eighteen (66.7%) patients gained more than 7% of their initial body weight. Mean weight gain was 9.2 kg over the study period for the first year 7.7 kg, and only 1.7 kg in the second year. Due to some patients losing weight in the second year, the latter finding obscures the fact that more than 50% of patients gained considerable weight also during the second year (4.8 kg). Weight gain per month was significantly higher in patients with lower body mass index, yet the highest weight gain was found in the most obese patient. Weight gain under olanzapine is a serious concern, and should be monitored closely and countered by active measures. © 2004 Lippincott Williams & Wilkins, Inc.