Introduction 3,4-methylenedioxymethamphetamine-assisted therapy (MDMA-AT) for post-traumatic stress disorder (PTSD) has demonstrated promise in multiple clinical trials. MDMA is hypothesized to facilitate the therapeutic process, in part, by decreasing fear response during fear memory processing while increasing extinction learning. The acute administration of MDMA in healthy controls modifies recruitment of brain regions involved in the hyperactive fear response in PTSD such as the amygdala, hippocampus, and insula. However, to date there have been no neuroimaging studies aimed at directly elucidating the neural impact of MDMA-AT in PTSD patients. Methods We analyzed brain activity and connectivity via functional MRI during both rest and autobiographical memory (trauma and neutral) response before and two-months after MDMA-AT in nine veterans and first-responders with chronic PTSD of 6 months or more. Results We hypothesized that MDMA-AT would increase amygdala-hippocampus resting-state functional connectivity, however we only found evidence of a trend in the left amygdala—left hippocampus (t = –2.91, uncorrected p = 0.0225, corrected p = 0.0901). We also found reduced activation contrast (trauma > neutral) after MDMA-AT in the cuneus. Finally, the amount of recovery from PTSD after MDMA-AT correlated with changes in four functional connections during autobiographical memory recall: the left amygdala—left posterior cingulate cortex (PCC), left amygdala—right PCC, left amygdala—left insula, and left isthmus cingulate—left posterior hippocampus. Discussion Amygdala—insular functional connectivity is reliably implicated in PTSD and anxiety, and both regions are impacted by MDMA administration. These findings compliment previous research indicating that amygdala, hippocampus, and insula functional connectivity is a potential target of MDMA-AT, and highlights other regions of interest related to memory processes. More research is necessary to determine if these findings are specific to MDMA-AT compared to other types of treatment for PTSD. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT02102802, identifier NCT02102802.

Background: Posttraumatic stress disorder (PTSD) is a debilitating mental health condition associated with serious adverse health outcomes and functional impairment. Previous MDMA–assisted therapy (MDMA-AT) studies have shown promising results in single site studies. Two open-label studies tested this modality in multisite clinical trials to assess the feasibility of scaling this manualized therapy across 14 North American sites. Method: Cotherapist dyads were trained in the manualized MDMA-AT protocol and administered three experimental sessions 3 to 5 weeks apart among participants with severe PTSD. Cotherapist dyads were provided clinical supervision and evaluated for protocol adherence by centralized raters. Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) assessed change in symptoms severity. Results: Adherence rating scores were high across cotherapist dyads ( M = 95.08%, SD = 3.70%) and sites ( M = 95.23%, SD = 2.20%). CAPS-5 scores decreased following 3 MDMA-AT sessions at 18 weeks post baseline (Δ M = −29.99, Δ SD = 13.45, p < .0001, n = 37, Cohen’s d = 2.2, confidence interval [1.97, 2.47]). MDMA was well tolerated. Conclusions: These findings corroborate previous results that MDMA-AT can achieve significant improvements in PTSD symptom severity and demonstrate scalability of manualized therapy across clinic sites in the United States and Canada.