Hippocampal gray matter increases following multimodal psychological treatment for combat‐related post‐traumatic stress disorder

INTRODUCTION: Smaller hippocampal volumes are one of the most consistent findings in neuroimaging studies of post‐traumatic stress disorder (PTSD). However, very few prospective studies have assessed changes in hippocampal gray matter prior to and following therapy for PTSD, and no neuroimaging studies to date have longitudinally assessed military populations. METHODS: A pilot study was conducted, assessing patients with combat‐related PTSD with structural MRI. Participants were then assigned either to a treatment group or waiting‐list control group. After the treatment group received multimodal psychological therapy for approximately 6 weeks, both groups completed a second neuroimaging assessment. RESULTS: Region‐of‐interest analysis was used to measure gray matter volume in the hippocampus and amygdala. There was a group by time interaction; the therapy group (n = 6) showed a significant increase in hippocampal volume and a nonsignificant trend toward an increase in amygdala volume following therapy, while no change was observed in the waiting‐list group (n = 9). CONCLUSIONS: This study provides initial evidence for increases in gray matter volume in the hippocampus in response to therapy for combat‐related PTSD.