Increased orbitofrontal cortex levels of choline in depressed adolescents as detected by in vivo proton magnetic resonance spectroscopy

Background: The frontal lobe has been implicated in the pathology of depression in adults. Through the use of magnetic resonance spectroscopy, altered brain choline levels have also been linked to the pathophysiology of affective disorders. Methods: To identify possible alterations in orbitofrontal cortex levels of cytosolic choline in adolescents with and without depression, 22 depressed and 43 control adolescents were recruited. Of those recruited, usable proton magnetic resonance spectra were acquired from a voxel in the left anterior medial frontal lobe of 17 depressed (mean age 15.8 ± 1.6) and 28 healthy adolescents (mean age 14.5 ± 1.7). Results: Orbitofrontal cytosolic choline/creatine (Cho/Cr) ratios (p = .032) and cytosolic choline/N-acetyl aspartate (Cho/NAA) ratios (p = .043) were significantly higher in the depressed subjects than in the control subjects. There were no significant differences between depressed and control subjects in gray or white matter content within the voxel. Conclusions: These findings suggest that brain cytosolic choline may be increased in depressed adolescents in comparison with control subjects and independent of a corresponding structural change. These results are consistent with similar, previously reported findings in adults and suggest that depression in adolescents is associated with alterations in orbitofrontal metabolism.