What are neurometabolites?

Products of normal chemical metabolism may be altered in schizophrenia. Changes in metabolite levels may be indicative of altered biochemical activity. Magnetic resonance spectroscopy (MRS) has been used to measure levels of neurometabolites, such as N-acetylaspartate (NAA), creatine (Cr), and glutamine (Gln). These derivatives are indirect indicators of biochemical activity. Alteration in levels of NAA/Cr is associated with the protective myelin sheath surrounding neurons, which is used as a marker of neural cell viability. Decreased levels of NAA are associated with neuron death, or injury to the part of the neuron that connects to other cells, the axon. Gln is a metabolite of the neurotransmitter, glutamate (Glu).

What is the evidence on neurometabolites?

Moderate and moderate to high quality evidence suggests NAA levels are reduced in people with schizophrenia compared to people without schizophrenia in the frontal lobe, temporal lobe, thalamus, hippocampus, cerebellum, and cingulate cortex. Lower quality evidence suggests NAA may also be reduced in the parietal lobe, basal ganglia, and occipital lobe (white matter only). NAA may be increased in the striatum and lenticular nucleus.

There are NAA reductions in the anterior cingulate and hippocampus of first-degree relatives of people with schizophrenia. People at clinical or genetic high-risk of schizophrenia show NAA reductions in the thalamus and NAA/Cr ratio reductions in the  prefrontal cortex.

Moderate to low quality evidence suggests small to medium-sized reductions in glutamate, and increases in glutamine levels in the frontal cortex of people with schizophrenia, which may progress with age.

March 2019

Last updated at: 4:30 am, 26th March 2019
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NeuRA Libraries

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