Study on Dorsolateral Prefrontal Cortex Neurochemical Metabolite Levels of Patients with Major Depression Using H-MRS...

. The aim of the study is to investigate, by using proton magnetic resonance spectroscopy (1H-MRS), the effects of major depression on the biochemistry of the brain, the relationship between the parametric changes demonstrated and cognitive functions, and the effects of antidepressant treatment.

The study included 30 patients, diagnosed with moderate/ severe non-chronic major depression disorder (NC-MDD) according to the DSM-5 diagnostic criteria, and 30 healthy individuals as the control group. The dorsolateral prefrontal cortex (DLPFC) areas of the patients and the control individuals were scanned bilaterally by 1H-MRS. The participants were also tested on the brief computerized version of the Wisconsin Card Sorting Test (or, Berg's "Wisconsin" Card Sorting TestWCST). After antidepressant treatment for a minimum of 8 weeks, the patients who scored below 7 on the Hamilton Depression Rating Scale (HAM-D), were assessed with the 1H-MRS scan and the WCST.

The Glx level in the left DLPFC was significantly lower in the patient group. Differences were not determined between the NAA, Cr, Cho levels in the right and the left DLPFC of the patient and the control groups. After the treatment, Glx level in the left DLPFC increased; but the levels of the other metabolites did not change. Before the treatment, the abilities of the patient group in changing strategy and problem solving, as assessed by the WCST, were lower in comparison to the control group. After the treatment the patient group improved clinically and performed significantly better on the WCST.

In the present neuroimaging (NI) study, it was determined that the Glx level in the left DLPFC of patients with moderate/severe NC-MDD improved together with the clinical features after treatment. Neurocognitive functions also improved after treatment. However, a correlation between the change in the metabolite levels and the performance on the WCST could not be demonstrated.