Background: Considerable patients with major depressive disorder (MDD) comorbid with anxious symptoms, referred as anxious depression. The neural structural basis of this MDD specifier remains largely unknown.
Methods: 104 patients with anxious depression, 57 MDD patients without significant anxious symptoms, and 160 healthy controls from single research center participated in the study with age and sex well-matched. We investigated gray matter alterations in anxious and non-anxious depression, explored different brain alterations between these two patient groups, and possible relationships between brain structural parameter and clinical information in patients.
Results: Gray matter volumes differed in the right inferior frontal gyrus, right orbital frontal gyrus, left postcentral gyrus, bilateral culmen and left cuneus among the three groups. Anxious depression had smaller gray matter volumes in the right inferior frontal gyrus and orbital frontal gyrus relative to both non-anxious depression and healthy controls. Patients with anxious depression presented larger gray matter volumes in the left postcentral gyrus than non-anxious depression, and larger gray matter volumes in the left cuneus than healthy controls. In addition, both patient groups showed larger gray matter volumes in bilateral culmen relative to healthy controls. Gray matter volumes in the left postcentral gyrus were positively associated with overall depression severity and anxiety factor scores in anxious depression.
Conclusion: Our study revealed brain structural abnormalities in emotional regulation and sensory processing regions of anxious depression, which may suggested distinct neurobiological mechanisms of this MDD specifier and could help explain different clinical manifestations in anxious depression from pure depression.
Keywords: Anxious depression; Emotional regulation; Gray matter; Non-anxious depression; Sensory processing.
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