Decreased baseline OXT levels have been reported in mixed samples of patients with schizophrenia with (Goldman et al., 2008) or without (Aydin et al., 2018) neuroendocrine dysfunction, and in males with schizophrenia (Jobst et al., 2014), while other studies reported elevated OXT levels in male schizophrenia patients (Legros et al., 1992) or in samples of more than 70% males (Walss-Bass et al., 2013; Strauss et al., 2015) compared to HCs. This evidence concerns the gene OXT and schizophrenia.