Mood, psychomotor, and cognitive function in major depressive disorder: from biomarkers to rapid-acting antidepressants

Excerpt

Patients with major depressive disorder (MDD) have psychomotor and cognitive impairments in addition to mood disorder. In this issue, Koo et al. [1] investigated the utility of combining biomarkers related to executive dysfunctions, motor activity, and neurophysiological patterns in patients with MDD (n = 20) and healthy control subjects (n = 20). Patients with MDD displayed significant impairments in executive functions and the reduction of daily motor activity. As measured by electroencephalogram (EEG) parameters (i.e., asymmetry in alpha power and reduction in alertness), patients with MDD showed increased right frontal lobe activity compared with left frontal lobe activity and lower brain arousal than that in healthy controls. Regression analysis showed that executive functions and alpha power asymmetry index in the EEG discriminated between patients with MDD and healthy controls with 78% accuracy. Furthermore, the interaction between motor activity and the EEG-vigilance stage alongside executive function increased the accuracy to 81%. This preliminary study suggests that combining these biomarkers results in a reliable biomarker for MDD. However, in this study, the patients with MDD were medicated with antidepressants, such as selective serotonin reuptake inhibitor (SSRI) or serotonin norepinephrine reuptake inhibitor (SNRI), although the antidepressants were discontinued 3 days before the investigation. Further study using a large sample size of drug-naïve patients with MDD is needed. …