Glutamatergic hypofunction in medication-free major depression: Secondary effects of affective diagnosis and relationship to peripheral glutaminase.

BackgroundThere is uncertainty as to whether alterations in glutamatergic function in affective disorders differ between unipolar and bipolar disorders and between depressive and euthymic states. Additionally, there are currently no available blood-based markers of central glutamatergic function to support clinical diagnosis and aid brain based investigations. MethodsIn this study, we measured levels of glutamate in the dorsal anterior cingulate cortex in-vivo using 1H-Magnetic Resonance Spectroscopy in medication free unipolar and bipolar patients (n=29, 20 unipolar and 9 bipolar) experiencing a major depressive episode, in comparison with a group of matched healthy controls (n=20). We als…