Anterior cingulate cortical thickness is a stable predictor of recovery from post-traumatic stress disorder

Abstract

Decreased cortical thickness in frontal and temporal regions has been observed in individuals suffering from post-traumatic stress disorder (PTSD), compared to healthy controls and trauma-exposed participants without PTSD. In addition, individual differences, both functional and structural, in the anterior cingulate cortex (ACC) have been shown to predict symptom severity reduction. Although there is some evidence suggesting that activity in this region changes as a function of recovery, it remains unknown whether there are any structural correlates of recovery from PTSD. Thirty participants suffering from moderate to severe PTSD underwent a magnetic resonance imaging (MRI) scan following an initial clinical assessment. A second assessment took place 6-9 months later. In addition, a subgroup of 25 participants completed a second MRI scan at that time. PTSD symptom severity changes over time were regressed against vertex-based cortical thickness. We found that cortical thickness in the right subgenual ACC (sgACC) predicted symptom improvement. Moreover, cortical thickness within this region of the ACC, measured 6-9 months later (n = 25), was also correlated with the same measure of symptom improvement. By contrast, no relationship was found between change in cortical thickness in this area and current PTSD symptom levels or degree of recovery. Our results suggest that sgACC thickness may be a stable marker of recovery potential in PTSD.