PROTON MAGNETIC-RESONANCE SPECTROSCOPY (H-1 MRS) OF THE HIPPOCAMPAL-FORMATION IN SCHIZOPHRENIA - A PILOT-STUDY

Background. Recent post-mortem and magnetic resonance imaging (MRI) st udies strongly suggest a decrease in the volume of the hippocampus and other limbic temporal structures in schizophrenia. Therefore, we hypo thesised that N-acetyl aspartate (NAA) which is found mainly in neuron s and which can be measured by proton magnetic resonance spectroscopy (H-1 MRS) would be decreased in the limbic temporal region in schizoph renia. Method. Consenting subjects fulfilling DSM-III-R criteria for s chizophrenia (n = 11) and matched healthy Volunteers (n = 11) who were recruited in a tertiary university referral centre, participated in a H-1 MRS brain study. Proton MRS spectra were obtained from a 12 cm(3) voxel (2 x 2 x 3 cm) in the right and left hippocampus/amygdala regio n. A researcher blind to the source of the spectra, measured the NAA i ntensity in all subjects, which were then statistically compared acros s the two groups. Results. NAA intensities were significantly reduced in the right hippocampus/amygdala region of schizophrenic patients (P = 0.038). The difference of the left side did not reach significance a t the 95% confidence level. Conclusions. The findings of decreased NAA in this study suggest that there may be a decrement in neuronal numbe r or tissue volume of the right hippocampal/amygdala region in schizop hrenia. Biochemical alterations in the metabolism of NAA in schizophre nia may be an alternative explanation. The findings are consistent wit h other types of post-mortem and in vivo evidence for hypoplasia of th e limbic temporal structures in schizophrenia, postulated to be of neu rodevelopmental pathogenesis.