NPY and schizophrenia: In an animal study using disrupted-in-schizophrenia 1 (DISC1) knockout (KO) mice as an animal model of schizophrenia, we found a reduction in the number and fiber length of NPY-immunoreactive (NPY-IR) neurons in the prefrontal cortex of DISC1 KO mice, suggesting that DISC1 dysfunction may be involved in the pathogenesis of schizophrenia through impairment of the NPY neural network (29).