ERBB4 and schizophrenia: These findings were contrary to the facts that patients with schizophrenia had high hippocampal NRG1 and ErbB4 levels (Petryshen et al. 2005; Hahn et al. 2006; Law et al. 2006) and that blocking NRG1/ErbB4 signaling improves cognitive impairment in these patients (Hasan et al. 2020).