Sleep Quality Improvements After MDMA-Assisted Psychotherapy for the Treatment of Posttraumatic Stress Disorder.

Sleep disturbances (SDs) are among the most distressing and commonly reported symptoms in posttraumatic stress disorder (PTSD). Despite increased attention on sleep in clinical PTSD research, SDs remain difficult to treat. In Phase 2 trials, 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy has been shown to greatly improve PTSD symptoms. We hypothesized that MDMA-assisted psychotherapy would improve self-reported sleep quality (SQ) in individuals with PTSD and be associated with declining PTSD symptoms. Participants in four studies (n = 63) were randomized to receive 2-3 sessions of active MDMA (75-125 mg; n = 47) or placebo/control MDMA (0-40 mg, n = 16) during all-day psychotherapy sessions. The PSQI was used to assess change in SQ from baseline to the primary endpoint, 1-2 months after the blinded sessions. Additionally, PSQI scores were measured at treatment exit (TE) and 12-month follow-up. Symptoms of PTSD were measured using the CAPS-IV. At the primary endpoint, CAPS-IV total severity scores dropped more after active MDMA than after placebo/control (-34.0 vs. -12.4), p = .003. Participants in the active dose group showed more improvement in SQ compared to those in the control group (PSQI total score ΔM = -3.5 vs. 0.6), p = .003. Compared to baseline, SQ had improved at TE, p < .001, with further significant gains reported at 12-month follow-up (TE to 12-months ΔM = -1.0), p = .030. Data from these randomized controlled double-blind studies provide evidence for the beneficial effects of MDMA-assisted psychotherapy in treating SDs in individuals with PTSD.

Posttraumatic Growth After MDMA-Assisted Psychotherapy for Posttraumatic Stress Disorder.

3,4-Methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for posttraumatic stress disorder (PTSD) has been shown to significantly reduce clinical symptomatology, but posttraumatic growth (PTG), which consists of positive changes in self-perception, interpersonal relationships, or philosophy of life, has not been studied with this treatment. Participant data (n = 60) were pooled from three Phase 2 clinical studies employing triple-blind crossover designs. Participants were required to meet DSM-IV-R criteria for PTSD with a score higher than 50 on the Clinician-Administered PTSD Scale (CAPS-IV) as well as previous inadequate response to pharmacological and/or psychotherapeutic treatment. Data were aggregated into two groups: an active MDMA dose group (75-125 mg of MDMA; n = 45) or placebo/active control (0-40 mg of MDMA; n = 15). Measures included the Posttraumatic Growth Inventory (PTGI) and the CAPS-IV, which were administered at baseline, primary endpoint, treatment exit, and 12-month follow-up. At primary endpoint, the MDMA group demonstrated more PTG, Hedges' g = 1.14, 95% CI [0.49, 1.78], p < .001; and a larger reduction in PTSD symptom severity, Hedges' g = 0.88, 95% CI [-0.28, 1.50], p < .001, relative to the control group. Relative to baseline, at the 12-month follow-up, within-subject PTG was higher, p < .001; PTSD symptom severity scores were lower, p < .001; and two-thirds of participants (67.2%) no longer met criteria for PTSD. MDMA-assisted psychotherapy for PTSD resulted in PTG and clinical symptom reductions of large-magnitude effect sizes. Results suggest that PTG may provide a new mechanism of action warranting further study.

A reconsideration and response to Parrott AC (2013) "Human psychobiology of MDMA or 'Ecstasy': an overview of 25 years of empirical research".

Parrott recently published a review of literature on MDMA/ecstasy. This commentary is a response to the content and tenor of his review, which mischaracterizes the literature through misstatement and omission of contrary findings, and fails to address the central controversies in the literature. The review makes several erroneous statements concerning MDMA-assisted psychotherapy, such as incorrect statements about research design and other statements that are baseless or contradicted by the literature. Though it critiques an attempt by other authors to characterize the risks of MDMA, the review fails to produce a competing model of risk assessment, and does not discuss potential benefits. Parrott does not represent an even-handed review of the literature, but instead recites dated misconceptions about neurotoxicity concerns involving the recreational drug ecstasy, which do not relate directly to the use of pure MDMA in a therapeutic setting. Unchallenged, Parrott's report may deter researchers from further investigating an innovative treatment that in early clinical trials has demonstrated lasting benefits for people with chronic, treatment-resistant post-traumatic stress disorder.

History and future of the Multidisciplinary Association for Psychedelic Studies (MAPS).

This article describes the teenage vision of the founder of the Multidisciplinary Association for Psychedelic Studies (MAPS) that humanity's future would be aided by the therapeutic and spiritual potential of psychedelic substances. The article traces the trajectory of MAPS from inception in 1986 to its present, noting future goals with respect to research, outreach, and harm reduction. MAPS was created as a non-profit psychedelic pharmaceutical company in response to the 1985 scheduling of 3,4-methylenedioxymethamphetamine (MDMA). Overcoming many hurdles, MAPS developed the first double-blind, placebo-controlled trial of MDMA-assisted psychotherapy for posttraumatic stress disorder (PTSD) and plans for FDA prescription approval in 2021. MAPS' program of research expanded to include a trial of lysergic acid diethylamide (LSD)-assisted psychotherapy for anxiety when facing life-threatening illness, observational studies of ibogaine in the treatment of addiction, and studies of MDMA for social anxiety in people with autism spectrum disorders. MAPS meets the challenges of drug development through a clinical research team led by a former Novartis drug development professional experienced in the conduct, monitoring, and analysis of clinical trials. MAPS' harm-reduction efforts are intended to avoid backlash and build a post-prohibition world by assisting non-medical users to transform difficult psychedelic experiences into opportunities for growth.

Concomitant medications associated with ischemic, hypertensive, and arrhythmic events in MDMA users in FDA adverse event reporting system.

3,4-Methylenedioxymethamphetamine (MDMA) is currently being investigated as an adjunctive treatment to therapy for posttraumatic stress and other anxiety related disorders in clinical trials. Within the next few years MDMA-assisted therapy is projected for approval by regulatory authorities. MDMA's primary mechanism of action includes modulation of monoamine signaling by increasing release and inhibiting reuptake of serotonin, norepinephrine, and, to a lesser extent, dopamine. This pharmacology affects sympathomimetic physiology. In controlled trials, special attention has been given to cardiovascular adverse events (AEs), because transient increases in heart rate and blood pressure have been observed during the MDMA-assisted therapy sessions. Finding and quantifying the potential drivers of cardiac AEs in clinical trials is difficult since only a relatively small number of participants have been included in these studies, and a limited set of allowed concomitant drugs has been studied. In this study a more diverse set of reports from the FDA Adverse Event Reporting System was surveyed. We found 17 cases of cardiovascular AEs, in which the individuals had taken one or more substances in addition to MDMA. Interestingly, all of those concomitant medications and illicit substances, including opioids, stimulants, anticholinergics, and amphetamines, had been previously associated with cardiovascular AEs. Furthermore, in none of the reports MDMA was marked as the primary suspect.

Breakthrough for Trauma Treatment: Safety and Efficacy of MDMA-Assisted Psychotherapy Compared to Paroxetine and Sertraline.

Unsuccessfully treated posttraumatic stress disorder (PTSD) is a serious and life-threatening disorder. Two medications, paroxetine hydrochloride and sertraline hydrochloride, are approved treatments for PTSD by the Food and Drug Administration (FDA). Analyses of pharmacotherapies for PTSD found only small to moderate effects when compared with placebo. The Multidisciplinary Association for Psychedelic Studies (MAPS) obtained Breakthrough Therapy Designation (BTD) from the FDA for 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for treatment of PTSD on the basis of pooled analyses showing a large effect size for this treatment. This review covers data supporting BTD. In this treatment, MDMA is administered with psychotherapy in up to three monthly 8-h sessions. Participants are prepared for these sessions beforehand, and process material arising from the sessions in follow-up integrative psychotherapy sessions. Comparing data used for the approval of paroxetine and sertraline and pooled data from Phase 2 studies, MAPS demonstrated that MDMA-assisted psychotherapy constitutes a substantial improvement over available pharmacotherapies in terms of safety and efficacy. Studies of MDMA-assisted psychotherapy had lower dropout rates compared to sertraline and paroxetine trials. As MDMA is only administered under direct observation during a limited number of sessions, there is little chance of diversion, accidental or intentional overdose, or withdrawal symptoms upon discontinuation. BTD status has expedited the development of MAPS phase 3 trials occurring worldwide, leading up to a planned submission seeking FDA approval in 2021. Appeared originally in Front Psychiatry 2019; 10:650.

MDMA-assisted therapy for posttraumatic stress disorder: A pooled analysis of ethnoracial differences in efficacy and safety from two Phase 2 open-label lead-in trials and a Phase 3 randomized, blinded placebo-controlled trial.

BACKGROUND: Limited ethnoracial diversity in previous ±3,4-methylenedioxymethamphetamine-assisted therapy (MDMA-AT) trials for posttraumatic stress disorder (PTSD) has prompted questions concerning whether Black, Indigenous, and People of Color (BIPOC) also benefit from this treatment. METHODS: Secondary analysis was conducted using a modified intent-to-treat sample pooled from two Phase 2 open-label trials and a Phase 3 randomized, blinded placebo-controlled trial to compare efficacy and safety of MDMA-AT for PTSD between BIPOC and non-Hispanic White participants. Four subgroups were of interest: MDMA-AT, BIPOC (n = 20); MDMA-AT, non-Hispanic White (n = 63); Placebo-assisted therapy (Placebo-AT), BIPOC (n = 17); and Placebo-AT, non-Hispanic White (n = 27). Planned comparisons tested subgroup differences in changes in Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) scores from baseline to primary endpoint, controlling for study type and baseline scores. Adverse events (AEs) on the day of (day 0) to 2 days post-dosing were reported for each subgroup. RESULTS: In the MDMA-AT group, no significant ethnoracial difference in CAPS-5 change scores was observed. In the Placebo-AT group, BIPOC participants trended toward greater reductions in CAPS-5 scores than non-Hispanic Whites. Among non-Hispanic Whites, MDMA-AT was accompanied by significantly greater reductions in CAPS-5 scores than Placebo-AT. No treatment difference emerged among BIPOC participants. AEs were mostly rated as mild or moderate across subgroups. CONCLUSIONS: These findings provide preliminary support for the efficacy and safety of MDMA-AT for treating PTSD across ethnoracial groups. There was also a trend toward greater efficacy with Placebo-AT among BIPOC participants. There was an imbalance in subgroups, highlighting the need for culturally responsive recruitment strategies to diversify future studies.

Reported Cases of Serotonin Syndrome in MDMA Users in FAERS Database.

3,4-Methylenedioxymethamphetamine (MDMA), is investigated as a treatment for post-traumatic stress disorder and other anxiety-related conditions in multiple placebo-controlled and open label studies. MDMA-assisted therapy is projected for approval by the United States Food and Drug Administration (FDA) and other regulatory agencies worldwide within the next few years. MDMA is a monoamine releaser and uptake inhibitor affecting serotonin, potentially increasing the risk of serotonin syndrome (SS). No instances of SS have occurred in clinical trials. The relatively small number of patients in controlled trials warranted a survey of FDA Adverse Event Reporting System data for the occurrence of SS in a larger database. We found 20 SS cases in people exposed to MDMA, all of which had also taken one or more substances with serotonergic properties in addition to MDMA, including amphetamines, stimulants, and opioids. There were no cases of SS associated with MDMA where MDMA was the sole reported compound taken.

Discontinuation of medications classified as reuptake inhibitors affects treatment response of MDMA-assisted psychotherapy.

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.

Integrating psychotherapy and psychopharmacology: psychedelic-assisted psychotherapy and other combined treatments.

INTRODUCTION: Combinations of psychotherapy with antidepressants are gold-standard psychiatric treatments. They operate through complex and interactional mechanisms, not unlike the reemergent paradigm of psychedelic-assisted psychotherapy, which promising research suggests may also be highly effective in even challenging populations. AREAS COVERED: We review the therapeutic mechanisms behind both conventional and psychedelic paradigms, including the evolution of this knowledge and the associated explanatory frameworks. We explore how psychedelics have provided insights about psychiatric illnesses and treatments over the past decades. We discuss limitations to early explanatory models while highlighting and comparing the psychological and biological mechanisms underlying many psychiatric treatments. METHODS: A narrative review was conducted based on a search in Medline/Pubmed up to January 1st, 2020, and iterative retrieval of references from recent reviews and clinical trials. EXPERT OPINION: The contextual model of the common factors of psychotherapy provides a powerful perspective on psychotherapy, antidepressants, and psychedelics, as well as 3,4-methylenedioxymethamphetamine (MDMA) and ketamine. It aligns well with key tenets of psychedelic-assisted psychotherapy. Conventional antidepressants and especially psychedelics may improve the efficacy of psychotherapy via neurochemical changes and increased environmental sensitivity. Combined treatments hold significant promise for advancing the knowledge and treatment of many forms of psychopathology.

Long-term follow-up outcomes of MDMA-assisted psychotherapy for treatment of PTSD: a longitudinal pooled analysis of six phase 2 trials.

RATIONALE: Posttraumatic stress disorder (PTSD) is a chronic condition that has wide-ranging negative effects on an individual's health and interpersonal relationships. Treatments with long-term benefits are needed to promote the safety and well-being of those suffering from PTSD. OBJECTIVES: To examine long-term change in PTSD symptoms and additional benefits/harms after 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for treatment of PTSD. METHODS: Participants received two to three active doses of MDMA (75-125 mg) during blinded or open-label psychotherapy sessions with additional non-drug therapy sessions. PTSD symptoms were assessed using the Clinician-Administered PTSD Scale for DSM IV (CAPS-IV) at baseline, 1 to 2 months after the last active MDMA session (treatment exit), and at least 12 months post final MDMA session (LTFU). A mixed-effect repeated-measures (MMRM) analysis assessed changes in CAPS-IV total severity scores. The number of participants who met PTSD diagnostic criteria was summarized at each time point. Participants completed a long-term follow-up questionnaire. RESULTS: There was a significant reduction in CAPS-IV total severity scores from baseline to treatment exit (LS mean (SE) = - 44.8 (2.82), p < .0001), with a Cohen's d effect size of 1.58 (95% CI = 1.24, 1.91). CAPS-IV scores continued to decrease from treatment exit to LTFU (LS mean (SE) = - 5.2 (2.29), p < .05), with a Cohen's d effect size of 0.23 (95% CI = 0.04, 0.43). The number of participants who no longer met PTSD criteria increased from treatment exit (56.0%) to LTFU (67.0%). The majority of participants reported benefits, including improved relationships and well-being, and a minority reported harms from study participation. CONCLUSIONS: PTSD symptoms were reduced 1 to 2 months after MDMA-assisted psychotherapy, and symptom improvement continued at least 12 months post-treatment. Phase 3 trials are investigating this novel treatment approach in a larger sample of participants with chronic PTSD. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00090064, NCT00353938, NCT01958593, NCT01211405, NCT01689740, NCT01793610.

MDMA-facilitated cognitive-behavioural conjoint therapy for posttraumatic stress disorder: an uncontrolled trial.

Cognitive-behavioural conjoint therapy (CBCT) for PTSD has been shown to improve PTSD, relationship adjustment, and the health and well-being of partners. MDMA (3,4-methylenedioxymethamphetamine) has been used to facilitate an individual therapy for PTSD. This study was an initial test of the safety, tolerability, and efficacy of MDMA-facilitated CBCT. Six couples with varying levels of baseline relationship satisfaction in which one partner was diagnosed with PTSD participated in a condensed version of the 15-session CBCT protocol delivered over 7 weeks. There were two sessions in which both members of the couple were administered MDMA. All couples completed the treatment protocol, and there were no serious adverse events in either partner. There were significant improvements in clinician-assessed, patient-rated, and partner-rated PTSD symptoms (pre- to post-treatment/follow-up effect sizes ranged from d = 1.85-3.59), as well as patient depression, sleep, emotion regulation, and trauma-related beliefs. In addition, there were significant improvements in patient and partner-rated relationship adjustment and happiness (d =.64-2.79). These results are contextualized in relation to prior results from individual MDMA-facilitated psychotherapy and CBCT for PTSD alone. MDMA holds promise as a facilitator of CBCT to achieve more robust and broad effects on individual and relational functioning in those with PTSD and their partners.

Se ha demostrado que la terapia conjunta cognitivo-conductual (TCCC) para el TEPT mejora TEPT, el ajuste de la relación, y la salud y el bienestar de las parejas. Se ha utilizado MDMA (3,4-metilendioximetanfetamina) para facilitar una terapia individual para el TEPT. Este estudio fue una prueba inicial acerca de la seguridad, tolerabilidad y eficacia de la TCCC facilitada por MDMA. Seis parejas con diferentes niveles de línea de base de su satisfacción en la relación de pareja, en las que uno de ellos fue diagnosticado con TEPT, participaron en una versión condensada del protocolo TCCC de 15 sesiones entregado durante 7 semanas. Hubo dos sesiones en las que a ambos miembros de la pareja se les administró MDMA. Todas las parejas completaron el protocolo de tratamiento y no hubo eventos adversos graves en ninguno de las parejas. Hubo mejorías significativas en los síntomas de TEPT evaluados por el médico, por el paciente y por la pareja (los tamaños del efecto antes y después del tratamiento/seguimiento variaron de d = 1,85 a 3,59), así como la depresión del paciente, el sueño, la regulación emocional y las creencias relacionadas con el trauma. Además, hubo mejorías significativas en la adaptación y satisfacción de la relación calificada por el paciente y la pareja (d =.64-2.79). Estos resultados se contextualizan en relación con los resultados anteriores de la psicoterapia individual facilitada por MDMA y TCCC solo para el TEPT. La MDMA se muestra prometedora como facilitadora de TCCC para lograr efectos más sólidos y amplios en el funcionamiento individual y relacional de las personas con TEPT y sus parejas.

MDMA-assisted psychotherapy for treatment of anxiety and other psychological distress related to life-threatening illnesses: a randomized pilot study.

The success of modern medicine creates a growing population of those suffering from life-threatening illnesses (LTI) who often experience anxiety, depression, and existential distress. We present a novel approach; investigating MDMA-assisted psychotherapy for the treatment of anxiety in people with an LTI. Participants with anxiety from an LTI were randomized in a double-blind study to receive MDMA (125 mg, n = 13) or placebo (n = 5) in combination with two 8-h psychotherapy sessions. The primary outcome was change in State-Trait Anxiety Inventory (STAI) Trait scores from baseline to one month post the second experimental session. After unblinding, participants in the MDMA group had one open-label MDMA session and placebo participants crossed over to receive three open-label MDMA sessions. Additional follow-up assessments occurred six and twelve months after a participant's last experimental session. At the primary endpoint, the MDMA group had a greater mean (SD) reduction in STAI-Trait scores, - 23.5 (13.2), indicating less anxiety, compared to placebo group, - 8.8 (14.7); results did not reach a significant group difference (p = .056). Hedges' g between-group effect size was 1.03 (95% CI: - 5.25, 7.31). Overall, MDMA was well-tolerated in this sample. These preliminary findings can inform development of larger clinical trials to further examine MDMA-assisted psychotherapy as a novel approach to treat individuals with LTI-related anxiety.Trial Registration: clinicaltrials.gov Identifier: NCT02427568, first registered April 28, 2015.

The Past and Future of Psychedelic Science: An Introduction to This Issue.

Psychedelic plants and fungi have been used in indigenous medicinal traditions for millennia. Modern psychedelic research began when Albert Hofmann first synthesized lysergic acid diethylamide (LSD-25) in 1938. Five years later, became the first person to ingest LSD. Hofmann was unaware of the significance of his actions, and the effects they would set in motion. After a burgeoning period of scientific and cultural exploration in the1950s and '60s, psychedelic research was slowed to a near halt. Throughout the 1970s and '80s governmental interventions severely hampered global psychedelic research, despite evidence of the limited medical risks and therapeutic potential of psychedelics. After decades of persistent education and advocacy, rigorous research employing psychedelics as tools of discovery and healing are abundant today. Studies are taking place in research institutions and in private practice sites supported by non-profit and for-profit organizations, as well as individual investigators. This research includes clinical trials with MDMA-assisted therapy for the treatment of PTSD, alcoholism, and social anxiety, and psilocybin clinical studies for depression and addiction, as well as the ability of psychedelics to catalyze spiritual or mystical experiences and inspire creativity, and into the neuroscientific understanding the effects of psychedelic substances on our nervous system.

Breakthrough for Trauma Treatment: Safety and Efficacy of MDMA-Assisted Psychotherapy Compared to Paroxetine and Sertraline.

Unsuccessfully treated posttraumatic stress disorder (PTSD) is a serious and life-threatening disorder. Two medications, paroxetine hydrochloride and sertraline hydrochloride, are approved treatments for PTSD by the Food and Drug Administration (FDA). Analyses of pharmacotherapies for PTSD found only small to moderate effects when compared with placebo. The Multidisciplinary Association for Psychedelic Studies (MAPS) obtained Breakthrough Therapy Designation (BTD) from the FDA for 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for treatment of PTSD on the basis of pooled analyses showing a large effect size for this treatment. This review covers data supporting BTD. In this treatment, MDMA is administered with psychotherapy in up to three monthly 8-h sessions. Participants are prepared for these sessions beforehand, and process material arising from the sessions in follow-up integrative psychotherapy sessions. Comparing data used for the approval of paroxetine and sertraline and pooled data from Phase 2 studies, MAPS demonstrated that MDMA-assisted psychotherapy constitutes a substantial improvement over available pharmacotherapies in terms of safety and efficacy. Studies of MDMA-assisted psychotherapy had lower dropout rates compared to sertraline and paroxetine trials. As MDMA is only administered under direct observation during a limited number of sessions, there is little chance of diversion, accidental or intentional overdose, or withdrawal symptoms upon discontinuation. BTD status has expedited the development of MAPS phase 3 trials occurring worldwide, leading up to a planned submission seeking FDA approval in 2021. Clinical Trial Registration: www.ClinicalTrials.gov, identifiers NCT00090064, NCT00353938, NCT01958593, NCT01211405, NCT01689740, NCT01793610.

MDMA-assisted psychotherapy for treatment of PTSD: study design and rationale for phase 3 trials based on pooled analysis of six phase 2 randomized controlled trials.

BACKGROUND: Posttraumatic stress disorder is a prevalent mental health condition with substantial impact on daily functioning that lacks sufficient treatment options. Here we evaluate six phase 2 trials in a pooled analysis to determine the study design for phase 3 trials of MDMA-assisted psychotherapy for PTSD. METHODS: Six randomized, double-blind, controlled clinical trials at five study sites were conducted from April 2004 to February 2017. Active doses of MDMA (75-125 mg, n = 72) or placebo/control doses (0-40 mg, n = 31) were administered to individuals with PTSD during manualized psychotherapy sessions in two or three 8-h sessions spaced a month apart. Three non-drug 90-min therapy sessions preceded the first MDMA exposure, and three to four followed each experimental session. RESULTS: After two blinded experimental sessions, the active group had significantly greater reductions in CAPS-IV total scores from baseline than the control group [MMRM estimated mean difference (SE) between groups - 22.0 (5.17), P < 0.001]. The between-group Cohen's d effect size was 0.8, indicating a large treatment effect. After two experimental sessions, more participants in the active group (54.2%) did not meet CAPS-IV PTSD diagnostic criteria than the control group (22.6%). Depression symptom improvement on the BDI-II was greatest for the active group compared to the control group, although only trended towards significant group differences [MMRM, estimated mean difference (SE) between groups - 6.0 (3.03), P = 0.053]. All doses of MDMA were well tolerated, with some expected reactions occurring at greater frequency for the active MDMA group during experimental sessions and the 7 days following. CONCLUSIONS: MDMA-assisted psychotherapy was efficacious and well tolerated in a large sample of adults with PTSD. These studies supported expansion into phase 3 trials and led to FDA granting Breakthrough Therapy designation for this promising treatment. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00090064, NCT00353938, NCT01958593, NCT01211405, NCT01689740, NCT01793610.