NRG1 and bipolar disorder: Given the broad-range functions of the NRG1/ErbB signaling system in the nervous system during development and in the adult, NRG1 and ErbBs have been implicated in several neuronal diseases of the CNS, e.g., schizophrenia (O’Donovan et al., 2008), bipolar disorder (Goes et al., 2009) or Alzheimer’s disease (Chaudhury et al., 2003), where pathophysiological genetics such as NRG1- polymorphism (Go et al., 2005) or abnormal protein or mRNA levels of NRG/ErbB signaling components have been associated (Mei and Nave, 2014).