PIK3CD and schizophrenia: The upregulation of transcripts of the NRG-ErbB signaling pathway in schizophrenia is reported [513], and it has been hypothesized that the abnormal expression of NRG and ErbB4, through the modulation of GABAergic and dopaminergic neurons, may contribute to the onset of schizophrenia is probably via an ErbB4-mediated mechanism exploiting PI3K/Akt signaling [514].