Gray matter volume alterations in generalized anxiety disorder and major depressive disorder

Area of Science:

• Neuroimaging
• Neuropsychiatry
• Brain Structure Analysis

Background:

• Generalized anxiety disorder (GAD) and major depressive disorder (MDD) frequently co-occur and exhibit overlapping clinical symptoms.
• Understanding the distinct and shared structural brain alterations in GAD and MDD is crucial for diagnosis and treatment.
• Voxel-based morphometry (VBM) is employed to investigate gray matter volume (GMV) differences.

Purpose of the Study:

• To investigate and compare gray matter volume (GMV) alterations in patients with GAD and MDD.
• To identify shared and differential structural brain changes between GAD and MDD using VBM.
• To correlate observed GMV changes with symptom severity in GAD and MDD patients.

Main Methods:

• 168 participants (42 GAD, 43 MDD, 83 healthy controls) underwent high-resolution MRI.
• Whole-brain VBM analysis compared GMV across groups, controlling for covariates.
• Post hoc and partial correlation analyses examined significant clusters and symptom severity.

Main Results:

• Significant GMV differences were identified in the left middle frontal gyrus, left postcentral gyrus, left putamen, and right superior frontal gyrus.
• Both GAD and MDD groups exhibited decreased GMV in the left middle frontal and postcentral gyri and increased GMV in the left putamen compared to controls.
• MDD patients uniquely showed decreased GMV in the right superior frontal gyrus, correlating with symptom severity.

Conclusions:

• GAD and MDD share GMV alterations in prefrontal, somatosensory, and striatal areas.
• Reduced GMV in the right superior frontal gyrus is a potential neuroimaging marker specific to MDD.
• These findings contribute to differentiating the neurobiological underpinnings of GAD and MDD.