Outcome Predictors for Three PTSD Treatments: Exposure Therapy, EMDR, and Relaxation Training

Several psychosocial treatments appear to be effective in treating posttraumatic stress disorder (PTSD). However, little is known about the predictors of treatment outcome. It is possible that some variables predict poor outcome for some treatments but not for other treatments. To investigate this issue, outcome predictors were investigated for three eight-session treatments: exposure therapy (entailing prolonged imaginal and in vivo exposure), relaxation training, and eye movement desensitization and reprocessing (EMDR). Sixty people with PTSD entered and 45 completed treatment. Treatments did not differ in attrition or perceived credibility. Exposure tended to be most effective, and EMDR and relaxation did not differ in efficacy. A number of clinical and cognitive variables were examined to identify predictors of treatment dropout as well as predictors of the likelihood that patients would be remitted from PTSD after treatment. These analyses were conducted by controlling for treatment condition. Low patient ratings of treatment credibility (assessed in session 2) predicted treatment dropout, regardless of treatment type. Severe reexperiencing symptoms (assessed prior to treatment) predicted poor outcome for relaxation training but not for the other therapies. These findings suggest that treatment outcome could be improved by improving treatment credibility. The findings also support the use of exposure therapy and, to a lesser extent, the use of EMDR in treating PTSD.