Elevated 3T proton MRS glutamate levels associated with poor Continuous Performance Test (CPT-0X) scores and genetic risk for schizophrenia.

Glutamate was quantified by proton magnetic resonance spectroscopy ((1)H-MRS) in the medial frontal lobes of 15 adult siblings of individuals with schizophrenia (HR) and 14 healthy volunteers (HV), all of whom also completed a Continuous Performance Test (CPT). Subjects were free of psychopathology but the HR group showed greater variability in glutamate levels. After median stratification, the high glutamate group contained a larger proportion of HR than HV subjects and scored lower on the CPT. Elevated glutamate may relate to poor sustained attention and elevated risk of schizophrenia, suggesting a potential role for glutamate in an endophenotype for schizophrenia.