Anterior cingulate cortex grey matter volume abnormalities in adolescents with PTSD after childhood sexual abuse

Adverse childhood experiences (ACE) substantially increase the risk of later psychiatric and somatic pathology. While neurobiological factors are likely to play a mediating role, specific insights are lacking. The scarce neuroimaging studies in traumatised pediatric populations have provided inconsistent results, potentially due to the inclusion of different types of trauma. To further improve our understanding of the neurobiology of pediatric psychotrauma, this study seeks to investigate abnormalities in grey matter volume (GMV) in a homogeneous group of adolescents with posttraumatic stress disorder (PTSD) due to childhood sexual abuse (CSA) and the relationship between GMV and symptom severity. We performed a voxel based morphometry (VBM) analysis in 21 adolescents with CSA-related PTSD and 25 matched non-traumatised, non-clinical adolescents. Hippocampus, amygdala, anterior cingulate cortex (ACC), medial PFC (mPFC) and superior temporal gyrus (STG) were chosen as regions of interest (ROIs). Trauma symptomatology was measured with the Trauma Symptom Checklist for Children (TSCC) and dissociation symptoms with the Adolescent Dissociative Experiences Scale (A-DES). The ROI analysis showed that the CSA-related PTSD group had significant smaller volumes of the dorsal ACC as compared to healthy controls. However, no correlations were found between GMV and scores on the TSCC and A-DES. The smaller ACC volume is partly in line with previous studies in traumatised youth and is a consistent finding in traumatised adults. Taken together our results suggest that the dorsal ACC is implicated in the neurobiological sequelae of CSA, potentially associated with an altered evaluative processing of emotion, but not directly with PTSD severity.