EMDR has been acknowledged as an evidence-based form of treatment for post-traumatic stress disorder in the United Kingdom by the National Institute for Clinical Excellence (2005), in America by the American Psychiatric Association (2004), in Australia by the Australian Centre for Posttraumatic Mental Health (2007), and in the Netherlands by the Dutch National Steering Committee for Guidelines for Mental Health Care (2003). However, the mechanism of action for the success of EMDR remains controversial (Rogers & Silver, 2002; Smyth & Poole, 2002).
Previous studies of traditional exposure techniques have emphasized that ‘reliving’ is a key process in recovery during treatment (Jaycox, Foa, & Morral, 1998). However, reliving was not associated with improvement in a study of key processes during EMDR for 44 participants with post-traumatic stress disorder (Lee, Taylor, & Drummond, 2006). Instead the greatest improvement occurred when clients gave distancing responses. ‘Distancing’ involved focusing on the trauma material but from an observational or detached perspective. Furthermore, cross-lagged panel correlations were consistent with the proposition that distancing was a consequence of the EMDR procedure rather than a response that covaried with improvement.
Although the findings from this study suggested that distancing during EMDR is related to improvement, they did not provide any evidence as to what ingredients of EMDR cause the distancing. Distancing could be promoted by two distinct mechanisms: therapist instructions or eye movement (Lee et al., 2006). For example, in the introduction to the desensitization phase, Shapiro (1995) recommended that the client be instructed to “Imagine you are on a train and the scenery is passing by. Just notice the scenery without trying to grab hold of it or make it significant” (p. 107). The emphasis in the process is “Let whatever happens happen” and “To just notice … whatever arises” (Shapiro, 1995: pp. 127–128). Smyth and Poole (2002) also observed that the therapist instructions during EMDR may encourage ‘mindful observation’ of the traumatic experience which is similar to the distancing concept described above. They likened the instructions during EMDR to the practice of mindful acceptance which has been recommended as an important process in facilitating treatment in traditionally difficult-to-treat populations (Linehan, 1993 and Segal et al., 2002).
Alternatively, eye movements themselves might generate distancing, perhaps by disrupting the “visuospatial sketchpad” (Andrade, Kavanagh, & Baddeley, 1997) or by producing a de-arousal effect through initiating an orienting response (Barrowcliff, Gray, Freeman, & MacCulloch, 2004). That eye movements do indeed promote distancing received empirical support from a study on the effects of eye movements, finger tapping, and a control condition not involving eye movement or finger tapping on the emotive memories of undergraduate students (van den Hout, Muris, Salemink, & Kindt, 2001). The memories were rated as less aversive after an exposure intervention accompanied by eye movements, but not after the other interventions. In addition, eye movements led to a greater reduction on a vividness measure. Similarly, the degree of aversiveness and degree of vividness of personal memories decreased significantly more during an exposure task accompanied by eye movement than by spatial tapping (Andrade et al., 1997).
A greater reduction in arousal and vividness for memories associated with fear and anxiety was also found for eye movement over an eye stationary condition using physiological measures of arousal (Barrowcliff et al., 2004). Finally, Kavanagh, Freese, Andrade, and May (2001) found that eye movement resulted in reduced ratings of distress and vividness compared to a no eye movement condition and a passive visual interference task.
The present study attempted to find which of the two ingredients of EMDR linked to the distancing response – eye movement or instructions – produce the most improvement in a non-clinical sample. Participants were randomly assigned to either an EMDR treatment, which involved eye movement, or an identical procedure that did not involve eye movement. In addition, therapists were instructed either to encourage the participant to take a distancing perspective on the traumatic memory or to maximize reliving in a manner similar to that which occurs during traditional exposure treatments. The objective was to test the effects of eye movement and distancing instructions on changes in vividness and emotional response immediately after treatment and at 1-week follow-up.
