Glutamate plus glutamine increased during psychotic exacerbations
MedWire News: Schizophrenia patients who are experiencing a psychotic exacerbation exhibit elevated levels of glutamate plus glutamine (Glx) in left inferior parietal white matter, results from a Japanese study show.
Miho Ota (National Center of Neurology and Psychiatry, Tokyo) and team explain that previous studies have suggested that glutamatergic dysfunction in the brain may play a role in schizophrenia.
However, they add that "little is known regarding changes in glutamate levels in the white matter in schizophrenia."
To investigate, the researchers studied 46 medicated patients with schizophrenia and 27 age- and gender-matched mentally healthy controls.
Of the patients with schizophrenia, 24 were experiencing a psychotic exacerbation at the time of the study. There were no significant differences between schizophrenia patients with and without psychotic exacerbation regarding age at onset, duration of illness, or negative or general subscales of the Positive and Negative Syndrome Scale (PANSS).
All of the participants were assessed for white matter levels of Glx in left frontal and left inferior parietal white matter using 1H magnetic resonance spectroscopy (MRS).
The researchers found that schizophrenia patients who were experiencing a psychotic exacerbation exhibited significantly higher Glx levels in left inferior parietal white matter than schizophrenia patients without a psychotic exacerbation and controls, at institutional values of 7.2 versus 6.6 and 6.5, respectively.
There were no significant differences among the groups regarding Glx levels in left frontal white matter.
The researchers note that there was a significant correlation between Glx levels in left parietal white matter and positive symptom subscale scores on the PANSS.
"These results suggest that glutamatergic dysfunction in the parietal white matter is involved in psychotic exacerbation," conclude Ota and team in Acta Psychiatrica Scandinavica.
They add: "If our results are replicated, the quantification of brain metabolites using MRS could be used as a good biomarker for exacerbation and could provide valuable hints to the brain pathology underlying the exacerbation of schizophrenia."
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By Mark Cowen