The hippocampus and parahippocampus in schizophrenia, suicide, and control brains.

Recent postmortem studies in schizophrenia have shown abnormalities in medial temporal lobe structures, including the hippocampus and parahippocampus. We tried to replicate previous studies and to explore the specificity of this finding to schizophrenia. The anterior hippocampus and parahippocampal cortex were evaluated for area and shape in postmortem tissue from 12 schizophrenic, 17 nonschizophrenic suicide, and 10 nonpsychiatric control brains. No significant differences were found in hippocampal area, but the parahippocampal cortex was significantly smaller in the schizophrenic group than in the control group. When parahippocampi from right and left sides were analyzed separately, both the suicide and schizophrenic groups had smaller parahippocampi on the right side than did the controls [corrected]. The suicide group exhibited greater parahippocampal areas in the left than in the right tissue samples within the group, while such a difference did not exist in the schizophrenic or control groups. This study demonstrated changes in temporal lobe structures in both schizophrenic and nonschizophrenic suicide groups.