Inflammatory biomarker outcomes associated with MDMA-assisted therapy: an open-label exploratory study

Background Posttraumatic stress disorder (PTSD) is associated with elevated inflammation and risk for chronic illness, yet few studies have examined inflammatory biomarker outcomes of PTSD interventions. Rapid PTSD symptom reduction has been observed following 3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy, which leverages MDMA as a prosocial adjunct to psychotherapy. No studies have evaluated inflammatory biomarker outcomes of MDMA-assisted therapy. This exploratory pilot study examined within-person changes in inflammatory biomarkers during MDMA-assisted group therapy for Veterans with PTSD ( www.clinicaltrials.gov , NCT05961527). Methods Blood plasma samples were collected from 23 Veterans at baseline and end-of-intervention. Hedges’ g effect sizes were calculated for interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and C-reactive protein (CRP). PTSD severity was assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at baseline and 30-day follow-up. Spearman’s rho correlations were calculated among biomarkers, PTSD symptoms, and change scores. Results Small increases were observed in IL-6 ( g = 0.24; 95% CI –0.25, 0.72) and CRP ( g = 0.23; 95% CI –0.30, 0.74), and a small decrease in TNF-α ( g = –0.24; 95% CI –0.69, 0.23). Baseline IL-6 and TNF-α were positively associated with baseline CAPS-5 scores (ρ = 0.45, 0.32). Higher baseline IL-6 weakly predicted symptom improvement (ρ = –0.25), and IL-6 change correlated with symptom change (ρ = 0.41). CRP showed weak negative associations with PTSD symptoms (ρ = –0.26). Conclusion Findings suggest MDMA-assisted therapy may modulate inflammatory biomarkers and highlight biomarker–symptom relationships. Results are preliminary but may inform larger studies.