2005]. The weight gain with the use of such medications is considerably higher, as shown in a meta-analysis of over 80 studies on weight change during antipsychotic treatment, which showed a mean weight gain of 4.15 kg after 10 weeks of olanzapine use, 4.45 kg increase with clozapine use and 2.10 kg with risperidone compared with 1.08 kg with the typical antipsychotic haloperidol [Davis et al. 2003]. In our

study, the weight gain after 8 weeks of olanzapine use was almost twice as high (7.9 kg) as the value mentioned above. Also, the observed SWG among our patients Inhibitors,research,lifescience,medical (reaching 63.3% after 2 Selleckchem SCH772984 months and 67% of the patients after 12 months) was considerably higher compared with previously published data

concerning both Inhibitors,research,lifescience,medical short- and long-term use of olanzapine that point to a SWG (≥7%) affecting 15–50% of patients [Bobes et al. 2003; Jaton et al. 2003; Kinon et al. 2005]. This magnitude of weight change is not usual with patients already using other antipsychotics previously, but such a higher rate of weight gain has already been observed in a drug-naive young population (mean age Inhibitors,research,lifescience,medical 26.7 years), in which 77.1% presented with SWG after 1 year [Perez-Iglesias et al. 2008]. In that study the authors argued that the greater weight change was probably due to patients’ characteristics (drug-naive young people with a low prevalence of obesity, Inhibitors,research,lifescience,medical 4%) and to good treatment compliance (low dropout rates, good family support), reflecting regular use of the drug. Some of these characteristics were similar in our population; they

were also young (mean age 26.8 years), with a low prevalence of obesity (13.3%), and presented good treatment compliance because the initial treatment occurred while they were inpatients in our ward. Still, only 20% of our subjects were drug naive, which lead us to other possible reasons for the greater weight gain. One reasonable explanation for this could be the higher doses administered to our patients (mean 20.5 mg in the first month and 24 Inhibitors,research,lifescience,medical mg in the last measure after 12 months), which means that we surpassed the labeled maximum recommended dose. Although some of the literature data indicate a dose-dependent effect of olanzapine on weight gain [Simon et al. 2009], our population first was too homogeneous to make this analysis possible. Almost all participants ended up using similar high doses of olanzapine, with no significant dose-dependent effect being observed in our study. The majority of the subjects included in our study were already using another antipsychotic without good response (80%), with all of them being acutely ill and needing treatment as inpatients in our ward, which generally demands fast titration and higher end doses of antipsychotics, and therefore they are more likely to present with greater side effects.