Brains of MDD patients show alterations in areas tied to positive emotions

The brains of medication-naive patients with major depressive disorder (MDD) exhibit interhemispheric structural imbalances in areas that regulate positive emotional processes, results of a small cross-sectional study suggest.

“To the best of our knowledge, asymmetric alterations in cortical thickness and subcortical volume in patients with MDD have not yet been reported,” wrote Zhiwei Zuo, of the department of radiology, Southwest Hospital, Army Medical University, Chongqing, China, and associates. “A comprehensive understanding of the cerebral pathophysiology changes in depression is essential and may lead to more targeted approaches for the prevention and treatment of MDD.”

The investigators enrolled 35 medication-naive, untreated patients with MDD from the hospital’s department of psychology, and 35 age-, gender-, and education-matched controls. Using whole-brain analysis, the investigators identified asymmetry in cortical thickness and subcortical volume that was mostly present in the cortical-striatal-pallidal-thalamic circuit. This part of the brain helps translate underlying positive affect processes into conscious feelings of pleasure, the authors reported. They noted that, although approaches to treating MDD previously have focused on diminishing negative emotional experiences, focusing instead on improving positive ones has begun to be taken more seriously in recent years (Clin Psychol Psychother. 2012 Jul-Aug;19[4]:326-40). The current study results were published in NeuroImage: Clinical.

Some limitations of the study include its small sample size and its cross-sectional nature. Nevertheless, they said, the findings could provide possible targets for therapeutic monitoring of the illness.

“These alterations were independent of depressive symptom severity, suggesting that cerebral asymmetry could be an appropriate indicator of morphological variations in mental disease,” the investigators noted.

The study was funded by the National Nature Science Foundation of China, the National Key Research and Development Plan of China, and the Innovative Talents Project of Southwest Hospital. The authors had no conflicts of interest to disclose.

cpalmer@mdedge.com

SOURCE: Zuo Z et al. Neuroimage Clin. 2019. doi: 10.1016/j.nicl.2018.101614.