Written Exposure Therapy vs Cognitive Processing Therapy

To the Editor Sloan and colleagues¹ reported noninferiority of 5-session written exposure therapy (WET) to 12-session cognitive processing therapy (CPT) in patients with posttraumatic stress disorder (PTSD). However, several aspects of the study require some clarification. First, was researcher allegiance controlled for? Written exposure therapy and CPT were carried out by the same therapists who were supervised by 2 of the authors. Second, the value of a noninferiority or equivalence study depends on how well the equivalence margin can be justified.²