Changes in gray matter volume of remitted first-episode, drug-naïve, panic disorder patients after 6-week antidepressant therapy

Objective: This study aimed to investigate changes in the gray matter volume (GMV) of first-episode, remitted drug-naïve patients under 6 weeks of escitalopram treatment for panic disorder (PD). We also determined any persistent GMV deficits after remission to assess for "state-dependent brain changes" and "trait-like brain changes" for PD. Method: 3-Tesla magnetic resonance imaging structural scans were performed on 21 PD patients at baseline and in their remitted state at week 6 of the study. To account for the inter-scanner bias, 21 healthy controls were also scanned twice within 6 weeks. All structural images were processed and analyzed to estimate GMV differences between patients and controls. We utilized optimized voxel-based morphometry with global brain volume, age, and gender as covariates. We also estimated the correlation between improvements in clinical rating scale scores and changes in total gray matter volumes to confirm the results of optimized voxel-based morphometry. Results: Rating scales of panic symptoms improved significantly (corrected p < 0.001). Remitted patients showed increased GMV in the left superior frontal gyrus (corrected p < 0.05) after escitalopram therapy. There were significant GMV deficits in the right precentral gyrus (corrected p < 0.05) after remission of PD symptoms. Changes in total GMV after remission were correlated with changes in clinical scores (r = 0.638; Spearman's rho p = 0.002). Conclusion: The left superior frontal gyrus (state-dependent brain changes) and the right precentral gyrus (trait-like brain changes) might be implicated in the underlying pathophysiology of PD.