EMDR therapy : crucial processes and effectiveness in a non-clinical and a post-war, cross-cultural context

The aim of this thesis was to clarify mechanisms that contributed to the treatment of adult posttraumatic stress disorder (PTSD) with eye movement desensitization and reprocessing therapy (EMDR). An initial review highlighted that: EMDR is efficacious for treatment of PTSD; the processes in EMDR differ from other PTSD treatments; controversy remained about the necessity and role of the eye movement (EM) component; and although the underlying mechanisms of EMDR remained unclear, evidence was emerging supporting orienting response, REM-sleep, and working memory theories of EMDR. The first study in this thesis investigated the necessity of EMs in EMDR, and the psychophysiological correlates of EM tasks used during therapy. Sixty-two non-clinical participants with negative autobiographical memories received a single EMDR session either without EMs, or with EMs of either varied or fixed rate of speed. EMDR-with-EMs led to greater reduction in distress than EMDR-without-EMs. Physiologically, when EMs began heart rate decreased significantly; skin conductance decreased during EM sets; heart rate variability and respiration rate increased significantly as EMs continued; and orienting responses were more frequent in the EM than no-EM condition at the start of exposure. Findings indicated that the eye movements in EMDR were beneficial, and were coupled with distinct psychophysiological changes that aid memory processing. A following study confirmed these findings by examining the effectiveness and physiological correlates of EMDR to treat trauma symptoms in a real world, post-war/conflict, developing nation, Timor Leste. Participants were 23 Timorese adults with symptoms consistent with PTSD, who served as their own waitlist control. EMDR was followed by significant and large reductions in PTSD symptoms, depression, and anxiety. Physiological responses associated with therapy confirmed changes seen previously in Western treatment sessions; physiological dearousal occurred within desensitisation sessions; heart rate decreased as EM sets began; skin conductance decreased within EM sets; and skin conductance responses that habituated in size and number in EM sets characteristic of an orienting response. Findings demonstrate EMDR can be effectively used cross-culturally, post-war/conflict, in Timor Leste, and this research adds to the body of theoretical knowledge as to how EMDR therapy works to facilitate processing of trauma memories