NOS1 and schizophrenia: Despite the important role of nitric oxide signalling in the hippocampus [47] and the above-described increase of NOS1AP mRNA in patients suffering from schizophrenia, a potential involvement of hippocampal NOS1AP and its interaction with the nNOS/PSD-95/NMDA receptor complex to different endophenotypes of severe mental disorders has not been investigated yet.