The adaptor protein NOS1AP, which interacts with the nNOS/PSD-95/NMDA receptor complex and links nNOS to downstream pathways, thus mediating their activation [34], has been linked to multiple mental disorders including depression, schizophrenia, PTSD, and related (endo)phenotypes [1,2,[6], [7], [8], [9], [10], [11], [12],67]. This evidence concerns the gene DLG4 and major depressive disorder.