Magnetic resonance imaging (MRI) scans revealed structural abnormalities in the brains of people with major depressive disorder or social anxiety disorder, according to a study presented last week at the annual meeting of the Radiological Society of North America in Chicago, Illinois.
“Our findings provide preliminary evidence of common and specific gray matter changes in major depressive disorder and social anxiety disorder patients,” said researcher Youjin Zhao MD, PhD, of Sichuan University in China.
Researchers analyzed and compared high-resolution MRI scans from 37 patients with major depressive disorder, 24 patients with social anxiety disorder, and 41 healthy control subjects.
Compared with healthy controls, patients with depression or social anxiety disorder showed gray matter abnormalities in the brain’s salience network, which determines which stimuli are deserving of attention, and the dorsal attention network, which plays a role in focus and attentiveness.
The differences pertained to thickening or thinning of the cortex, researchers reported. For instance, patients with depression or social anxiety showed cortical thickening in the insular cortex, a region vital to perception and self-awareness, and the anterior cingulate cortex, which is associated with emotion.
“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,” said Dr. Zhao. “Second, greater anterior cingulate cortical thickness could be the result of both the continuous coping efforts and emotion regulation attempts of major depressive disorder and social anxiety disorder patients.”
The scans also showed disorder-specific involvement of the brain's “fear circuitry” in patients with social anxiety disorder and the visual recognition network in patients with depression.
“Future studies with larger sample sizes combined with machine learning analysis may further aid the diagnostic and prognostic value of structural MRI,” Dr. Zhao said.