Although participants in the mindfulness-based stress reduction group were more likely to show clinically significant improvement in self-reported PTSD symptom severity ( 48.9 % vs 28.1 % with present-centered group therapy ; difference , 20.9 % ; 95 % CI , 2.2 % -39.5 % ; P = .03 ) at 2-month follow-up , they were no more likely to have loss of PTSD diagnosis ( 53.3 % vs 47.3 % , respectively ; difference , 6.0 % ; 95 % CI , -14.1 % to 26.2 % ; P = .55 ) .