Uniform abnormalities in the hippocampus of five chronic schizophrenic men compared with age-matched controls.

In a post-mortem study five chronic schizophrenic men were matched with respect to age and sex to five control subjects without a known history of psychiatric illness, and were compared in pairs with regard to neurone number and pyramidal cell orientation in the left hippocampus. All five schizophrenics had significantly more disoriented pyramidal cells in the Cornu Ammonis subregions CA1-CA3 than their matched controls. They also had significantly fewer pyramidal cells in the observed areas of CA1 and CA3, but not in CA2 and CA4. There was no difference in the number of granular cells of the dentate gyrus. In pairwise comparisons the pattern was never reversed with respect to these two parameters, except in a single case where one schizophrenic proband had more cells in subregion CA2. In the absence of gliosis the findings were interpreted as sequelae of an early, presumably prenatal, injury.