• Why is it important to determine why a treatment works and not simply whether it works? A new and 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. Carefully controlled studies demonstrate the therapeutic benefits of using EMDR in treating PTSD (e.g., Chen, Zhang, et al., 2015; Cusack et al., 2015;

Oren & Solomon, 2012; van den Berg et al., 2015). However, one recent study showed that exposure therapy is more effective than EMDR in treating veterans with PTSD (Haagen et al., 2015).