Examining structural brain changes in patients with PTSD following cognitive processing therapy

Posttraumatic stress disorder (PTSD) is a psychiatric condition occurring following exposure to psychological trauma. Neuroimaging studies have highlighted neuroanatomical differences in individuals with PTSD. Cognitive Processing Therapy (CPT) is an evidence-based frontline treatment for PTSD. Although CPT has shown success in decreasing clinical symptom severity, its underlying neural mechanisms remain unclear. We hypothesize that structural changes occur following CPT within key brain regions that have previously been linked to PTSD.

Fifty-six participants, including patients with PTSD (n = 32) and healthy controls (n = 24), underwent T₁-weighted structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) scans at baseline and follow-up. The PTSD group completed a twelve-week CPT treatment, while the controls did not undergo any treatment. To investigate the effects of successful CPT treatment, four participants who did not respond to treatment were excluded from analyses. T1-weighted images were analyzed using voxel-based morphometry and cortical thickness was estimated within pre-defined regions-of-interest. Fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were estimated using DTI.

Significant interactions between group and time were observed in both grey matter (GM) and white matter (WM) volume analyses - decreased left thalamic GM volume and increased left cerebellar WM volume were observed in patients with PTSD, following CPT treatment. Furthermore, a significant interaction between group and time showed increased fractional anisotropy in the left cerebellum following treatment in the PTSD group. Cortical thickness and other DTI-related measures did not differ.

Our findings suggest that CPT leads to neuroanatomical changes in the thalamus and the cerebellum, and these may be associated with lasting effects of CPT-related benefits in PTSD.