Hippocampal neuronal dysfunction in schizophrenia as measured by proton magnetic resonance spectroscopy

Previous neuropathological and neuroimaging studies have documented neuronal loss in the hippocampal region in schizophrenia. N-acetylaspartate (NAA) is a neuronal/axonal marker that may be utilized to assess neuronal loss or dysfunction by proton magnetic resonance spectroscopy (1H MRS). This study measured NAA, choline, and creatine in the hippocampal region of patients with schizophrenia using in vivo proton magnetic resonance spectroscopic imaging (1H MRSI).

1H MRSI was performed on the right and left hippocampal regions in 30 chronic schizophrenic patients and 18 control subjects. Concentration estimates of NAA, creatine, and choline were determined.

Relative to the control group, the patients with schizophrenia demonstrated significantly lower NAA in both the right and left hippocampal regions. No group differences in choline were noted; however, there was a trend for creatine to be higher on the left than the right hippocampus in the schizophrenic group. There was also no association between NAA and duration of illness or medication dosage.

This preliminary study provides support for neuronal dysfunction and/or decreased neuronal density in the hippocampal region. The absence of choline signal elevation does not support accelerated turnover of membrane phospholipids, which might be expected if there were ongoing neuronal atrophy or neuronal necrosis.