FOS and schizophrenia: One study in particular chose to use repeated subanesthetic doses of ketamine (30 mg/kg) for 5 consecutive days in order to provide evidence for the usefulness of ketamine for obtaining a legitimate animal model for schizophrenia and they reported significant changes in nitrergic and GABAergic systems similar to those observed in the schizophrenic human brain, but they also observed an increase in the density of reduced nicotinamide adenine dinucleotide phosphate diaphorase, neuronal nitric oxide synthase, and cFOS-positive hippocampal interneurons [46].