ERBB4 and schizophrenia: Additionally, evidence from genetic, post-mortem and animal studies over the past decade has identified a number of susceptibility factors for schizophrenia, including neuregulin 1 (Nrg1) and its receptor ErbB4, disrupted-in-schizophrenia-1 (DISK1), catechol-O-methyl transferase (COMT), BDNF, and Akt, along with their related pathways, that interact closely with dopaminergic, glutamatergic, and GABAergic neurotransmitter systems (Karam et al., 2010).