This study represents a methodologically rigorous attempt to assess the long-term impact of CBT on PTSD. In the original trial, participants receiving either CPT or PE showed marked improvements in PTSD and depression, from pretreatment to posttreatment. There were few differences between the two treatments in the outcomes. During the follow-up period, PE participants exhibited small decreases in self-reported PTSD symptoms that approached but did not reach statistical significance. Participants in the PE condition also tended (i.e., had an effect that approached but did not reach statistical significance) to have fewer people relapse based on PTSD diagnosis. The ITT examination of diagnostics indicates that 22.2% of CPT and 17.5% of PE participants met the CAPS diagnosis for PTSD at the LTFU. Importantly, the groups did not differ in the amount of improvement that was sustained over the long term. The maintenance of treatment gains throughout the follow-up period, on average 6 years, exhibited by both is impressive, especially considering that these women continued to experience life events that might impact their symptoms. The sustained treatment effects were not accounted for by further psychotherapy after completing one of these treatments or by medication usage at the LTFU. In fact, additional psychotherapy and medication were associated with worse outcomes. In the original trial (Resick et al., 2002
), 20% of each group were considered to be nonresponders. Given the strong maintenance of the results of the trial, it might be concluded that those who started medications and received more therapy after the trial continued to be nonresponders.
The original and current follow-up study excluded as few participants as possible so the sample would represent the full range of PTSD clients seen in the community, including those with complex trauma histories and presentations. Only those with imminent harm, active psychosis, illiteracy, and substance dependence were referred for immediate care, and those with medication instability were included once their medications had been stabilized. We made great efforts to include as many participants as possible who were originally randomized to the trial. Therefore, these findings should generalize to women with PTSD and comorbid depression, anxiety disorders, personality disorders, and so forth.
Future research can address limitations of this study by conducting similar clinical trials and LTFU with samples that include men, wider ethnic diversity, and different types of trauma, such as combat. It is unknown whether other trauma populations will have the same long-term results. Because the LTFU was not preplanned, the follow-up assessment had a 5-year time span. Although linear mixed-effects modeling can account for variability in length of time between assessments, it is not clear if the results would have changed if the data had been collected at a single uniform time point. Strengths of the study include the high response rate for the LTFU and the inclusion of all randomized participants from the original trial, not just the treatment completers. It should be noted, however, that this sample includes women who never started treatment, about a quarter who dropped out before completing the full protocol, and some who were nonresponders initially. Despite that, this study found that over 85% of participants who were randomized to one of the two brief treatments reported clinically reliable improvements at an LTFU assessment conducted an average of 6 years later. Unlike the situation with other psychological disorders, which have a high relapse rate, it appears that, in most cases, treatment improvements of PTSD symptoms and diagnosis are long-lasting. Furthermore, comorbid major depression showed the same pattern of sustained recovery. Finally, in the parent study, the women were in their 30s on average. The fact that they reported an increase in education and more stable relationships may be a proxy for improved functioning.