The role of hair endocannabinoid concentrations in clinical symptoms and treatment outcome in female inpatients with posttraumatic stress disorder

Background: While available posttraumatic stress disorder (PTSD) treatments are generally successful, 30–40% of patients show limited improvement. The endocannabinoid system may play a role in the aftermath of trauma, in PTSD, and in extinction processes. Therefore, this secondary analysis of a randomized-controlled trial including PTSD inpatients over the course of trauma-focused treatment investigated whether a dysregulated endocannabinoid system is associated with symptom severity and treatment response. Methods: Fifty-four female PTSD inpatients provided hair samples and completed psychometric questionnaires at admission, discharge, and 3-month follow-up. Endocannabinoid (EC: AEA, 1AG/2AG) and N-acylethanolamine (NAE: SEA, OEA, PEA) concentrations were measured in scalp-near 3-cm hair segments. Results: At admission, higher hair AEA correlated with lower depressive and anxiety and higher PTSD symptoms (when controlling for depressive symptoms). Hair NAEs associated with more traumatic experiences. PTSD symptoms improved across treatment, remaining stable at follow-up, but were predicted neither by pre-treatment hair ECs/NAEs nor their changes. Subgroup analyses with those who received exposure treatment tentatively indicated a trend linking higher hair PEA and OEA to lower PTSD symptoms at discharge. Conclusions: Taken together, hair ECs/NAEs may relate differentially to trauma exposure and symptom severity, but not to PTSD inpatient treatment response. Larger-scale research is necessary to confirm this.