The predictive value of dorsal cingulate activity and fractional anisotropy on long-term PTSD symptom severity

Background: Posttraumatic stress disorder (PTSD) can be treated with trauma-focused therapy, although only about 50% of the patients recover on the short-term. In order to improve response rates it is important to identify who will and will not recover from trauma-focused therapy. Although previous studies reported dorsal anterior cingulate cortex (ACC) activity, as well as dorsal cingulum bundle white matter microstructure integrity as markers for the persistence of PTSD symptoms on the short-term, it remains unclear whether these markers also predict long-term PTSD symptom severity. Methods: PTSD patients (n = 57) were investigated with clinical interviews and an MRI protocol before the start of treatment. Clinical interviews were repeated after 6-8 months of treatment (short-term follow-up), and on average 4 years later (long-term follow-up). Twenty-eight PTSD patients returned for the long-term follow-up. Dorsal ACC activity in response to negative images, and fractional anisotropy (FA) of the dorsal cingulum were the neural markers investigated. Results: In this long-term follow-up sample (n = 28), dorsal ACC activity and dorsal cingulum FA values significantly predicted CAPS scores on short- and long-term follow-up. The results remained significant after controlling for baseline CAPS score, early trauma, and comorbidity. Conclusion: This study confirms the importance of the cingulate cortex activation and white matter integrity not only for short-term treatment outcome, but also for PTSD long-term symptom severity. Future treatments should target ACC function in particular during treatment in order to improve response rates.