The distribution of neuropeptide Y (NPY) containing neurons was investigated in the dorsal prefrontal region in the brains of the schizophrenic patients and compared to those of normal control. Proportional comparison of NPY neurons in four compartments, upper cortical layers, lower cortical layers, subcortical white matter and deep white matter, demonstrated differential distribution between schizophrenic brains and controls. The proportion of NPY neurons in the upper cortical layers was low in disorganized form and subsequently in paranoid form in comparison to controls. The proportion of NPY neurons in the deep white matter was, conversely, high in the disorganized form and subsequently in the paranoid form. These results indicate that there may be a gamma-aminobutyric acid (GABA)-ergic deficit in schizophrenic patients, especially, in the disorganized form. These results also support the hypothesis of neurodevelopmental dysfunction of schizophrenia.