Rationale: MDMA-assisted psychotherapy is under investigation as a novel treatment for posttraumatic stress disorder (PTSD). The primary mechanism of action of MDMA involves the same reuptake transporters targeted by antidepressant medications commonly prescribed for PTSD.
Objectives: Data were pooled from four phase 2 trials of MDMA-assisted psychotherapy. To explore the effect of tapering antidepressant medications, participants who had been randomized to receive active doses of MDMA (75-125 mg) were divided into two groups (taper group (n = 16) or non-taper group (n = 34)).
Methods: Between-group comparisons were made for PTSD and depression symptom severity at the baseline and the primary endpoint, and for peak vital signs across two MDMA sessions.
Results: Demographics, baseline PTSD, and depression severity were similar between the taper and non-taper groups. At the primary endpoint, the non-taper group (mean = 45.7, SD = 27.17) had a significantly (p = 0.009) lower CAPS-IV total scores compared to the taper group (mean = 70.3, SD = 33.60). More participants in the non-taper group (63.6%) no longer met PTSD criteria at the primary endpoint than those in the taper group (25.0%). The non-taper group (mean = 12.7, SD = 10.17) had lower depression symptom severity scores (p = 0.010) compared to the taper group (mean = 22.6, SD = 16.69). There were significant differences between groups in peak systolic blood pressure (p = 0.043) and diastolic blood pressure (p = 0.032).
Conclusions: Recent exposure to antidepressant drugs that target reuptake transporters may reduce treatment response to MDMA-assisted psychotherapy.
Feduccia, A. A., Jerome, L., Mithoefer, M. C., & Holland, J. (2021). Discontinuation of medications classified as reuptake inhibitors affects treatment response of MDMA-assisted psychotherapy. Psychopharmacology, 238(2), 581–588. https://doi.org/10.1007/s00213-020-05710-w