A unique increase in prefrontal gray matter volume in hoarding disorder compared to obsessive-compulsive disorder

<div><p>Background</p><p>Hoarding disorder (HD) is a disease concept newly presented in DSM-5. As far as we know, no studies have examined the structural changes relevant to hoarding by applying the diagnostic criteria of HD in DSM-5. In the present study, we aimed to find abnormalities in gray matter (GM) structures of patients with HD.</p><p>Methods</p><p>Seventeen patients who met the DSM-5 criteria for HD, 17 obsessive-compulsive disorder (OCD) patients, and 17 healthy controls (HCs) participated in this study. All participants underwent MRI scanning of the brain by a 3.0-Tesla MRI scanner. In a voxel-based morphometric procedure, preprocessed GM structural images were used to compare the three groups. Thereafter we investigated the correlation between the clinical data (age of onset, symptomatic severity) and GM volume.</p><p>Results</p><p>The HD group showed a significantly increased GM volume compared to the OCD and healthy control groups (p<0.05) in both Brodmann area (BA)10 and BA11. There was no significant difference between OCD and healthy control groups. No significant correlation between the clinical data including age of onset, symptom severity score, and GM volume was observed in HD and OCD groups.</p><p>Conclusions</p><p>The results might help to explain the inconsistency of previous studies. As with OCD, HD is considered to have cognitive dysfunction as its basis. This result is convincing after considering the clinical features of HD and suggested that structural abnormalities in the prefrontal regions might relate to the pathophysiology of HD.</p></div

The results of correlation analysis.

<p>No significant correlation between the DY-BOCS dimensional score (HD: hoarding score, OCD: contamination/washing score) and GM volume was observed in either the HD or OCD group.</p

Demographic and clinical characteristics of all subjects.

<p>Demographic and clinical characteristics of all subjects.</p

Differences in GM volumes among three groups (HD, OCD, and HCs).

<p>Differences in GM volumes among three groups (HD, OCD, and HCs).</p

The results of ROI analysis.

<p>In the comparison of the three groups based on the gray matter volume obtained by ROI analysis, the HD group showed significantly increased GM volumes compared to the OCD group and the healthy control group (p<0.05) in both BA10 and BA11.</p

The results of VBM analyses.

<p>In voxel-based analysis of variance (ANOVA), three groups (HD, OCD, and HCs) exhibited the presence of significant regional GM volume differences in the right prefrontal regions. The initial voxel threshold was set to 0.001 uncorrected. Clusters were considered as significant when falling below a cluster-corrected p (FWE) = 0.05. The cluster size was 1228 voxels, and the p value was 0.004. Peak coordinates (Montreal Neurological Institute) were x = 20, y = 64, z = -18.</p