???????? ????Why is it important to determine why a treatment works and not simply whether it works? A controversial technique has emerged in the treatment of PTSD—eye movement desensitization and reprocessing

(EMDR) treatment (Shapiro, 2001). In EMDR, the client is asked to form a mental picture of an image associated with the trauma while the therapist rapidly moves a finger back and forth in front of the client’s eyes for about 20 to 30 seconds. While holding the image in mind, the client is asked to move his or her eyes to follow the therapist’s finger. The client then relates to the therapist the images, feelings, bodily sensations, and thoughts that were experienced during the procedure.

The procedure is then repeated until the client becomes desensitized to the emotional impact of this disturbing material.

Evidence from carefully controlled studies demonstrates the therapeutic benefits of EMDR in treating PTSD (e.g., Leiner et al., 2012; Oren & Solomon, 2012; Sharpless & Barber, 2011; Tarquinio, Rydberg, & Oren, 2012). The controversy is not about whether EMDR works, but why it works and whether the key feature of the technique—the eye movements themselves—is a necessary factor in explaining its effects (Karatzias et al., 2011; Lohr, Lilienfeld, & Rosen, 2012;

van den Hout et al., 2011).