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Intermediate Biomarker for Schizophrenia?

Role of glutamate and GABA in mismatch negativity

The role of glutamate and γ-aminobutyric acid (GABA) play a role in mismatch negativity, serving as a biomarker for schizophrenia, according to a study involving 98 individuals.

Participants included those with schizophrenia (n=45) and controls (n=53) who completed an electroencephalographic session for mismatch negativity, magnetic resonance spectroscopy for glutamate and GABA, and a digit sequencing task. Investigators used a structural equation model to test how neurochemistry and mismatch negativity impacted performance on the digit sequencing task.

Among the results:

• Mismatch negativity amplitude and glutamate were reduced in the schizophrenia group.

• Smaller mismatch negativity amplitude was significantly linked with lower GABA level, lower glutamate level, and higher ratio of glutamine to glutamate.

• Reduced mismatch negativity amplitude was associated with poor verbal working memory in schizophrenia.

Modeling revealed evidence that mismatch negativity serves as an intermediate biomarker linking glutamatergic function to digit sequencing task performance.

Citation: Rowland L, Summerfelt A, Wijtenburg A, et al. Frontal glutamate and γ-aminobutyric acid levels and their associations with mismatch negativity and digit sequencing task performance in schizophrenia. [Published online ahead of print December 30, 2015]. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2015.2680.