N-acetylaspartate and N-Acetylaspartylglutamate deficits in superior temporal cortex in schizophrenia and bipolar disorder: a postmortem study

Background N-acetylaspartylglutamate is found in neurons and its metabolite N-acetylaspartate, which can be measured by magnetic resonance spectroscopy, is considered a marker of neuronal integrity. Several magnetic resonance spectroscopy studies have found evidence of N-acetylaspartate deficits in schizophrenia. Methods We employed a high-pressure liquid chromatography method to determine N-acetylaspartate and N-acetylaspartylglutamate in postmortem brain tissues taken from a well-defined series of psychiatric cases. N-acetylaspartate and N-acetylaspartylglutamate concentrations were measured in superior temporal and frontal cortices of patients with schizophrenia, bipolar disorder, and depression and control subjects. Results N-acetylaspartate was significantly decreased below controls in superior temporal cortex in schizophrenia (p< .01) and bipolar disorder (p< .01), but no deficits were found in frontal cortex. N-acetylaspartylglutamate was significantly decreased only in superior temporal cortex in schizophrenia. Conclusions The results are consistent with evidence of superior temporal cortex abnormalities in schizophrenia. The finding in bipolar disorder suggests that temporal cortex N-acetylaspartate deficits may be a common feature of psychotic disorders.