Morphovolumetric changes after EMDR treatment in drug-naïve PTSD patients

Few studies have investigated the effects of efficacious psychotherapy on structural alterations of discrete brain regions associated with posttraumatic stress disorder (PTSD). We therefore proposed to evaluate the neurobiological effects of eye movement desensitization and reprocessing (EMDR) on 19 patients with drug-naive PTSD without comorbidity, matched with 19 untreated healthy controls.We administered the Clinician Administered PTSD Scale (CAPS) and conducted brain MRI measurements (with Optimized Voxel-Based Morphometry). Patients received 12 EMDR sessions over three months. Then patients and controls were reassessed.At baseline, grey matter volume (GMV) differed significantly between patients and controls (F 1,35 =3.674; p=.008; η 2=.298). Analyses of 3-month scans showed no changes for controls, while significant changes were highlighted for patients post-EMDR, with a significant increase in GMV in left parahippocampal gyrus, and a significant decrease in GMV in the left thalamus region. The diagnosis of PTSD was effectively eliminated in 16 of 19 patients, reflected in a significant improvement on the CAPS (t(35)=2.132, p<.004).Results indicated post-EMDR changes for patients in brain morphology. We discuss whether EMDR’s mechanism of action may work at the level of the thalamus, an area implicated in PTSD pathology.