King's College London

Objective: The authors conducted a comprehensive metaanalysisof MRI region-of-interest and voxel-based morphometry(VBM) studies in posttraumatic stress disorder(PTSD). Because patients have high rates of comorbid depression, an additional objective was to compare the findingsto a meta-analysis of MRI studies in depression.

Method: The MEDLINE database was searched for studiesfrom 1985 through 2016. A total of 113 studies met inclusioncriteria and were included in an online database. Of these,66 were selected for the region-of-interest meta-analysisand 13 for the VBM meta-analysis. The region-of-interestmeta-analysis was conducted and compared with a metaanalysisof major depressive disorder. Within the regionof-interestmeta-analysis,three subanalyses were conducted that included control groups with and without trauma.

Results: In the region-of-interest meta-analysis, patients with PTSD compared with all control subjects were found tohave reduced brain volume, intracranial volume, and volumesof the hippocampus, insula, and anterior cingulate. PTSDpatients compared with nontraumatized or traumatized controlsubjects showed similar changes. Traumatized comparedwith nontraumatized control subjects showed smallervolumes of the hippocampus bilaterally. For all regions, pooledeffect sizes (Hedges’ g) varied from 20.84 to 0.43, andnumber of studies from three to 41. The VBM meta-analysisrevealed prominent volumetric reductions in the medial prefrontal cortex, including the anterior cingulate. Compared with region-of-interest data from patients with major depressive disorder, those with PTSD had reduced total brain volume, and both disorders were associated with reduced hippocampal volume.

Conclusions: The meta-analyses revealed structural brainabnormalities associated with PTSD and trauma and suggestthat global brain volume reductions distinguish PTSDfrom major depression.