Initially, a few studies showed improvement in schizophrenia patients who received oxytocin,24–28 but subsequent studies failed to replicated these findings,29–35 meta-analyzed in Martins et al and Zheng et al.22,36 Those studies which found the clearest evidence for efficacy used a high dose of oxytocin, above 50 IU/day24,26; consequently our study evaluated oxytocin at 72 IU/day. This evidence concerns the gene OXT and schizophrenia.