The human striatum in schizophrenia. II. Increased number of striatal neurons in schizophrenics

In neuropathological studies of schizophrenia, alterations of the basal ganglia are one main topic. Using the optical dissector, we performed an unbiased estimation of neurons and glia cells in the human striatum. To rule out an influence of age and gender, the brains of 9 male schizophrenic patients younger than 65 were closely matched in age with the brains of 9 male control persons. Absolute neuron numbers of the striatum and its subdivisions putamen and nucleus caudatus/nucleus accumbens of both hemispheres were compared between both groups, as were absolute glia cell numbers and the calculated glia index. We found a significant increase in absolute striatal neuron numbers in the schizophrenic group on the right side (P = 0.008**) and only a trend to higher absolute striatal neuron numbers on the left side. In a further analysis, the significant increase of absolute striatal neuron numbers in the right striatum of the schizophrenic group was only discernible for the nucleus caudatus/nucleus accumbens complex (P = 0.01*) and not for the putamen. Absolute striatal glia cell numbers did not differ significantly between both groups, neither on the right nor on the left side. There was only a trend towards a smaller glia index on both sides. Cortical development disturbances with a consecutive reduction of naturally occurring cell death during development could be responsible for this increase in absolute striatal neuron numbers in schizophrenics.