Issues in the design of multisite clinical trials of psychotherapy: VA Cooperative Study No. 494 as an example.

This article describes issues in the design of an ongoing multisite randomized clinical trial of psychotherapy for treating posttraumatic stress disorder (PTSD) in female veterans and active duty personnel. Research aimed at testing treatments for PTSD in women who have served in the military is especially important due to the high prevalence of PTSD in this population. VA Cooperative Study 494 was designed to enroll 384 participants across 12 sites. Participants are randomly assigned to receive 10 weekly sessions of individual psychotherapy: Prolonged Exposure, a specific cognitive-behavioral therapy protocol for PTSD, or present-centered therapy, a comparison treatment that addresses current interpersonal problems but avoids a trauma focus. PTSD is the primary outcome. Additional outcomes are comorbid problems such as depression and anxiety; psychosocial function and quality of life; physical health status; satisfaction with treatment; and service utilization. Follow-up assessments are conducted at the end of treatment and then 3 and 6 months after treatment. Both treatments are delivered according to a manual. Videotapes of therapy sessions are viewed by experts who provide feedback to therapists throughout the trial to ensure adherence to the treatment manual. Discussion includes issues encountered in multisite psychotherapy trials along with the rationale for our decisions about how we addressed these issues in CSP #494.