PTSD psychotherapy improves blood pressure but leaves HPA axis feedback sensitivity stable and unaffected: First evidence from a pre-post treatment study

Abstract Although key to development of tailored drugs for augmentation treatment of psychotherapy for posttraumatic stress disorder (PTSD), the biological correlates of PTSD remission are still unknown, probably because pre-post treatment studies searching for them are rare. Not even the feedback sensitivity of the otherwise well-studied hypothalamic-pituitary-adrenal (HPA) axis nor arterial blood pressure (BP), which was previously reported to be elevated in PTSD patients, have so far been analyzed during PTSD treatment. To narrow this knowledge gap, we first performed an overnight dexamethasone suppression test (DST) in a mixed-sex cohort of 25 patients with severe PTSD vs. 20 non-traumatized healthy controls (nt-HC). In addition to hormones, BP and heart rate (HR) were measured at each of the four assessment points (APs). Second, the same parameters were assessed again in 16 of these patients after 12 sessions of integrative trauma-focused cognitive behavioral therapy (iTF-CBT). In relation to nt-HC, PTSD patients showed a significant elevation in HR and diastolic BP while their systolic BP, DST outcomes and basal serum cortisol levels (BSCL) were not significantly altered. In response to iTF-CBT, PTSD symptoms and dysfunctional stress coping strategies improved significantly in PTSD patients. Most important, also their systolic and diastolic BP levels ameliorated at distinct APs while their DST outcomes and BSCL remained unchanged. To our knowledge, this is the first pre-post treatment study assessing the stability of the DST outcome and BP levels during PTSD treatment. Our results provide first evidence for a non-involvement of HPA axis feedback sensitivity in PTSD symptom improvement and, furthermore, suggest a possible role for BP-regulating pathways such as the sympathetic nervous system in PTSD remission. Limitations arise from the small sample size, the lack of an untreated patient group and drug treatment of patients.