Despite the fact that the three above-mentioned studies were performed in relatively small and obviously underpowered samples (21, 25, and 39 patients), clozapine demonstrated significant superiority over active comparator antipsychotic compounds in trials of different lengths (6, 8, and 12 weeks). It was rather unusual, and testified to the considerable magnitude of its effect. A systematic review of clozapine data in EOS by Schneider et al included not only RCTs but also open-label and retrospective studies.10 The authors also concluded that clozapine showed superior efficacy compared with other antipsychotics in the treatment of patients with refractory EOS.