Objectives:
The aim of this study was to determine neurochemical alterations in bipolar disorder using proton magnetic resonance spectroscopy (1H-MRS).

Methods:
We investigated a group of 27 patients diagnosed with bipolar disorder (with manic and mixed episodes, depression and after remission of symptoms) and 10 healthy subjects. MR imaging and 1H-MRS were performed on a 1.5 T scanner. Voxels of 8 cm3 were positioned in the anterior cingulate, left frontal lobe and left temporal lobe. Spectral peaks of NAA (N-acetylaspartate), Glx (glutamate/glutamine/GABA complex), Cho (choline), Cr (creatine/phosphocreatine) and mI (myo-inositol) were analyzed and the ratios of these metabolites to creatine (Cr) and non-suppressed water signal were determined.

Results:
In the anterior cingulate cortex of patients with bipolar disorder a significantly higher Cho/H2O ratio (p = 0.029) and a trend toward higher Cho/Cr ratio values (p = 0.096) were observed as compared to healthy controls.

Conclusions:
The findings of our study prove that neurochemical changes occurring in the anterior cingulate cortex of bipolar patients are related to altered choline levels.