Post-traumatic stress disorder : neurobiology and effects of eye movement desensitization and reprocessing

Abstract

The aim of this study was to evaluate a new psychotherapy method, eye movement desensitization and reprocessing (EMDR) in the treatment of post-traumatic stress disorder (PTSD) and to study the biological reactions in PTSD during a script-driven symptom provocation.

PTSD is a disorder that may occur after a major psychological trauma. It is characterised by the phenomenon of reliving, bringing the person back to the sensations and reactions that prevailed during the traumatic event. This intrusion is often followed by avoidance of trauma-related reminders, irritability and emotional numbing. The disorder is longstanding to chronic and is a major contributor to psychiatric morbidity.

In this study drivers and other personnel in the Stockholm public transportation system participated. The subjects had experienced a person under train accident or assault at work. Fifty-three subjects, one-third women, participated and were diagnostically evaluated as PTSD or non-PTSD subjects. They were assessed with interview based and self-evaluation symptom scales. In comparison these two groups differed sharply in the scores on psychiatric symptoms, social functioning and well-being. The trauma load was higher in the PTSD group as compared to the non-PTSD group.

The 21 subjects diagnosed with PTSD were randomly assigned to a treatment group and a waiting-list control group. The primary outcome variable was remission of PTSD. The treatment with EMDR followed the standard protocol. The therapy was given in five one-and-a-half hour sessions. When the therapy group was compared with the waiting list group there were significant differences in remission rate (67%, 11%, respectively) and in the interview based scales.

Subsequently, also the waiting-list group received therapy and 20 subjects completed therapy which was assessed immediately after treatment, at eight months and at 35 months. The initial positive results remained and were consolidated (remisson rate 65% at 35 months). There was also significant improvement over time in social functioning and work capacity. The effect size comparing scores on the Global Assessment of Functioning (GAF) scale before treatment and at 35 months, was for the total treatment group 1.3 and in the immediate remitters 3.0.

Heart rate and blood pressure increased significantly during the symptom provocation, both in the PTSD and the non-PTSD group and also both before and after therapy, irrespective of outcome. This was evaluated as a reaction to a fear signal which was not identical with the anxiety reaction that characterised the PTSD group.

The total group reacted after the symptom provocation with increased blood flow distribution in the right hemisphere and this was more pronounced in the PTSD subjects and even more in the assaulted subjects. The PTSD group showed higher activity in limbic areas involved in memory and emotion. After therapy there was a trend towards normalisation of tracer distribution with a decrease in limbic and an increase in pre-frontal areas. There was no difference in the size of the hippocampi in the PTSD and the non-PTSD group, but such a difference was observed comparing the remitters with the non-remitters.

Summarising, we found that EMDR was effective in ameliorating PTSD symptoms in this sample and we also found physiological differences in PTSD subjects as compared to non-PTSD subjects regarding regional cerebral blood flow.