Grey matter reduction associated with posttraumatic stress disorder and traumatic stress

• We analyse disease- or traumatic stress-related neural mechanisms in PTSD.
• We distinguish different brain structural alterations in PTSD.
• We analyse brain structural alterations in medication-free PTSD patients.
• We addressed two key issues related to PTSD: type of event and time since trauma.

In recent decades, many imaging studies have reported brain structural alterations in posttraumatic stress disorder (PTSD). However, due to differences in the selection of control subjects, it is difficult to conclude whether the observed alterations were related to disease or traumatic stress. The present study was to provide a quantitative voxelwise meta-analysis of grey matter (GM) changes in PTSD relative to either trauma-exposed controls without PTSD (TEC) or non-traumatised healthy controls (HC) separately and to conduct a systematic review of voxel-based morphometry (VBM) studies that compared trauma-exposed individuals with HC to explore the effect of traumatic stress. GM reduction was identified in the medial prefrontal cortex in PTSD compared to both TEC and HC. Additional GM reduction was also observed in PTSD in the left hippocampus, left middle temporal gyrus and right superior frontal gyrus compared with TEC. Additionally, GM decreased in the left occipital cortex in PTSD compared with HC. The present study delimited the significant differences among VBM results in PTSD research when different control groups were chosen.