Background: The aim of this study was to evaluate the relationship between N-acetylaspartate (NAA) levels in selected brain regions and cognitive performance in patients with first-episode schizophrenia.
Material and Methods: Thirty patients (20 male, 10 female; mean age: 22.5 years) with the diagnosis of first-episode schizophrenia and 19 comparable healthy controls were studied. The Wisconsin Card Sorting Test (WCST) was used to assess cognitive functions. MR imaging and MR spectroscopy examinations were performed on a 1.5 T scanner. Voxels of 8 cm3 were positioned in the left frontal lobe, left temporal lobe, and left thalamus. The ratio of NAA to creatine and the ratio of NAA to unsuppressed water signal were analyzed.
Results: Patients performed significantly worse than controls on measures of the WCST. In the patient group, NAA levels in the frontal lobe were significantly related to poorer WCST performance.
Conclusions: Cognitive impairment related to dysfunction of the prefrontal cortex in first-episode schizophrenia is associated with NAA level in the frontal lobe.

Keywords: Antipsychotic Agents - therapeutic use, Aspartic Acid - metabolism, Cognition Disorders - physiopathology, Frontal Lobe - physiopathology, Neuropsychological Tests, Schizophrenia - physiopathology