ERBB4 and major depressive disorder: Neurogenesis and synaptogenesis are among critical processes in brain development and function that might have a causal role in psychiatric disorders.82, 83 In particular, hippocampal neurogenesis is associated with learning, memory and synaptic plasticity.84 Abnormal hippocampal neurogenesis is associated with depression and several psychiatric disorders.85 In the present study, several genes including DLGAP1, NRXN3, ERBB4, DLG2, WNT3, APBA1, NRG3, ERC2, PARK2, LARGE and ACTG2 from G1 were involved in neurogenesis-related processes.