Researchers have discovered a common pattern of structural abnormalities in the brains of people with depression and social anxiety, according to a new study by Sichuan University in Chengdu, China.
Major depressive disorder (or simply depression) and social anxiety disorder (an intense fear of being watched and judged by others) share some clinical symptoms, suggesting the two disorders may have similar brain mechanisms. However, few studies have directly compared the structural effects of the two disorders on the brain.
The researchers used MRI to assess alterations in the brain’s grey matter among MDD and SAD patients. They focused on the thickness of the cortex, which is the outer layer of the cerebrum, or principal part of the brain.
The researchers analysed high-resolution images from 37 MDD patients, 24 SAD patients and 41 healthy control individuals. Both MDD and SAD patients, relative to healthy controls, showed grey matter abnormalities in the brain’s salience and dorsal attention networks. The salience network is a collection of brain regions that determine which stimuli are deserving of our attention, while the dorsal attention network plays an important role in focus and attentiveness.
Dr. Youjin Zhao, the study’s lead author, said: ‘Our findings provide preliminary evidence of common and specific grey matter changes in MDD and SAD patients. Future studies with larger sample sizes combined with machine learning analysis may further aid the diagnostic and prognostic value of structural MRI.’
The differences between the MDD and SAD patients and the healthy controls related to either thickening or thinning of the cortex. Both MDD and SAD patients showed cortical thickening in the insular cortex, a brain region vital to perception and self-awareness.
Zhao said: ’First, it is possible that a greater cortical thickness may reflect a compensatory mechanism that is related to inflammation or other aspects of the pathophysiology. Second, greater anterior cingulate cortical thickness could be the result of both the continuous coping efforts and emotion regulation attempts of MDD and SAD patients.’