Differential Imbalances of Brain Glutamate/GABA in Patients with Bipolar Disorder and Unipolar Depression

Background: Bipolar disorder is often misdiagnosed as unipolar depression in clinical practice although both of them are thought to be associated with the dysfunction of glutamate/GABA transmission. Recent studies have detected the changes in glutamate and GABA levels by means of magnetic resonance spectroscopy (MRS) in patients with bipolar disorder and unipolar depression, but these results are inconsistent. Methods: We have reviewed some of recent human studies measuring brain glutamate and GABA concentrations in patients with bipolar disorder and unipolar depression and summarized the differences between them. Results: BD and UD patients show contrasting directions in Glx changes and different changes in GABA levels. Conclusion: We proposed to distinguish bipolar from unipolar depression by comparing the profiles of glutamate and GABA concentrations in the two disorders.