Effects of psychotherapy on 99mTc-HMPAO distribution in Post-Traumatic Stress Disorder

Background Post-traumatic stress disorder (PTSD) is a derangement of mood control with emotional trauma recollections that may follow psychological trauma. It is treated with pharmacological and cognitive therapies as well as with eye movement desensitization and reprocessing (EMDR). However, a limited number of studies have been published dealing with job related PTSD, and an even smaller number have assessed the effects of treatment on CBF. The aim of this study was to investigate the short term outcome of occupation based PTSD after EMDR therapy by 99mTc-HMPAO SPECT. Methods Fifteen patients suffering PTSD after having experienced a person under train accident or having been assaulted at work were included into the study. 99mTc-HMPAO SPECT was performed before and after EMDR therapy while listening to a script portraying the traumatic event. Tracer distribution analysis was performed at VOI level using a 3D standardised brain atlas and at cluster of voxel level by SPM and was subjected to an analysis of treatment as well as contrasted to a group of 27 subjects exposed to the same psychological trauma and not developing PTSD. Results Eleven of 15 patients responded to treatment, i.e. they did no longer fulfil the DSM-IV criteria for PTSD after EMDR. Overall VOI analysis showed significant differences between, both before and after treatment conditions and controls (p<0.05) but no effect of period, i.e. treatment. However, when contrasting responders to controls the significant group difference present after treatment disappeared, indicating a normalization effect due to successful EMDR treatment. SPM analysis showed significant uptake differences in orbitofrontal cortex (Brodmann 11) and temporal pole (Brodmann 38) before as well as after treatment as compared to controls. A significant tracer uptake group difference present before treatment in uncus (Brodmann 36) disappeared after treatment while a significant difference appeared in lateral temporal lobe (Brodmann 21). No tracer uptake differences were found by SPM as an effect of treatment, nor between the 11 responders and controls. Conclusion Significant 99mTc-HMPAO uptake differences, mainly in peri-limbic cortex, between PTSD patients investigated before and after EMDR and subject exposed to trauma not developing PTSD were found. Differences between the tracer distribution in patients before and after therapy were not significant neither at SPM nor at VOI analyses but the latter showed at group level an effect of symptom remission on tracer distribution. The
findings underscore the validity of psychotherapy in anxiety disorders and confirm the efficacy of SPECT in psychiatry.