Accumulated reports have indicated that depression may be linked to the lack of hippocampal neurogenesis, which is negatively influenced by neuronal nNOS-derived NO, thus suggesting that the overexpression of nNOS in the hippocampus is necessary for chronic stress-induced depression, and inhibiting nNOS signaling in the brain may mitigate these debilitating effects [79].‎ Moreover, the dysregulation of NO signaling can hinder the regenerative abilities of neural stem cells (NSCs) causing an exacerbation in cognitive impairment associated with depression. This evidence concerns the gene NOS1 and depressive symptom measurement.