ERBB4 and diabetes mellitus: ErbB4 is a susceptibility factor for schizophrenia, and a large number of studies have shown that impairment of ErbB4 signaling pathway contributes to schizophrenia.[11a] Hence, ErbB4 is a common susceptibility gene for schizophrenia and diabetes, which partly explains why people with schizophrenia are more likely to develop diabetes.[34]