By contrast, low levels of oxytocin were related to the severity of symptoms in patients with schizophrenia, especially to negative and cognitive symptoms (Shilling and Feifel, 2016), leading to the proposal of exogenously administering oxytocin to manage these symptoms (Kirsch, 2015; Shilling and Feifel, 2016). This evidence concerns the gene OXT and schizophrenia.