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PTSD (Post-traumatic stress disorder)

A central target for MDMA-assisted therapy and related trauma-focused interventions.

State of the evidence

Synthesized

Synthesized from 19 studies in the library · AI-generated, grounded in the abstracts below

Found by searching the library for PTSD, post-traumatic stress disorder, traumatic stress, then ranked by relevance.

Research indicates that MDMA-assisted therapy and ketamine infusions can significantly reduce PTSD symptoms compared to placebo or active control, with large effect sizes in several randomized trials, though evidence is tempered by small samples, blinding challenges, and limited long-term follow-up. Psilocybin-assisted therapy shows preliminary promise in an open-label pilot, and non-drug interventions like mindfulness-based cognitive therapy and a digital nonattachment program also report significant symptom reductions. Overall, findings are consistent in supporting these interventions' efficacy, but durability, safety in broader populations, and comparative effectiveness remain key caveats.

Evidence by study

Direction is which way each study's own result points, not our rating of the study. All 24 matching studies were reviewed; the 19 that directly address the question are shown here.

What the directions mean
Supports:
the study found the intervention worked, or its hypothesis held.
Opposes:
it found the opposite, no benefit or a harm.
No effect:
no significant difference either way.
Mixed:
effects in both directions within the same study.
Unclear:
the abstract does not report a direction.
MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study. 2021
Supports

MDMA-assisted therapy produced significantly greater reductions in PTSD symptoms and functional impairment than placebo, with a large effect size on the primary outcome and no serious adverse events.

randomized controlled trial Sample size: 90

The safety and efficacy of {+/-}3,4-methylenedioxymethamphetamine-assisted psychotherapy in subjects with chronic, treatment-resistant posttraumatic stress disorder: the first randomized controlled pilot study. 2010
Supports

MDMA-assisted psychotherapy reduced PTSD symptoms more than placebo therapy in people with chronic, treatment-resistant PTSD.

randomized controlled pilot study

Efficacy of Intravenous Ketamine for Treatment of Chronic Posttraumatic Stress Disorder 2014
Supports

A single ketamine infusion produced a significantly greater reduction in PTSD symptom severity at 24 hours compared to midazolam.

randomized controlled trial Sample size: 41

3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for post-traumatic stress disorder in military veterans, firefighters, and police officers: a randomised, double-blind, dose-response, phase 2 clinical trial. 2018
Supports

The active dose of MDMA-assisted psychotherapy led to significant and lasting reductions in PTSD symptoms compared to a lower dose.

randomized, double-blind, dose-response, phase 2 clinical trial

A randomized, controlled pilot study of MDMA (±3,4-Methylenedioxymethamphetamine)-assisted psychotherapy for treatment of resistant, chronic Post-Traumatic Stress Disorder (PTSD) 2012
Mixed

MDMA-assisted psychotherapy was safe and produced clinically and statistically significant self-reported improvement in PTSD symptoms, but clinician-rated reductions were not statistically significant.

randomized controlled trial Sample size: 12

MDMA-assisted therapy for moderate to severe PTSD: a randomized, placebo-controlled phase 3 trial. 2023
Supports

MDMA-assisted therapy reduced PTSD symptoms and functional impairment more than placebo with therapy in a diverse population with moderate to severe PTSD.

randomized controlled trial Sample size: 104

Durability of improvement in post-traumatic stress disorder symptoms and absence of harmful effects or drug dependency after 3,4-methylenedioxymethamphetamine-assisted psychotherapy: a prospective long-term follow-up study. 2013
Supports

MDMA-assisted psychotherapy provided durable symptom relief for most participants over an average of 45.4 months, with no reported harm, though two subjects relapsed.

long-term follow-up of a completed trial Sample size: 19

A PILOT STUDY OF GROUP MINDFULNESS-BASED COGNITIVE THERAPY (MBCT) FOR COMBAT VETERANS WITH POSTTRAUMATIC STRESS DISORDER (PTSD) 2013
Supports

Group mindfulness-based cognitive therapy adapted for combat PTSD led to significant and clinically meaningful reductions in PTSD symptom severity and trauma-related cognitions compared to treatment-as-usual.

quasi-experimental with treatment-as-usual comparison group Sample size: 37

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder. 2021
Supports

Repeated ketamine infusions significantly reduced PTSD symptom severity compared to midazolam, with a large effect size and a 67% responder rate at two weeks.

randomized controlled trial Sample size: 30

Healing together: Results from a pilot trial of 3,4-Methylenedioxymethamphetamine-enhanced cognitive-behavioral conjoint therapy for posttraumatic stress disorder. 2026
Supports

MDMA-enhanced cognitive-behavioral conjoint therapy was feasible and acceptable, and was associated with clinically meaningful reductions in PTSD symptoms and improvements in relationship satisfaction.

pilot trial

Efficacy of a Digital Nonattachment-Based Intervention for Post-traumatic Stress Symptoms: A Randomised Controlled Trial 2026
Supports

Compared with waitlist, the digital nonattachment-based intervention produced significantly greater reductions in PTSD symptoms at 8 and 20 weeks with large between-group effect sizes.

randomized controlled trial Sample size: 141

PSYCHEDELICS IN THE TREATMENT OF POST-TRAUMATIC STRESS DISORDER AND DEPRESSION: A REVIEW OF CLINICAL TRIALS 2026
Supports

The review confirms that psilocybin-assisted therapy reduces depression symptoms and MDMA-assisted therapy shows robust PTSD symptom reduction in two phase three trials, but notes limitations including small samples, blinding issues, and short follow-ups.

review

Blood biomarker changes in response to low-dose oral ketamine treatment in adults with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) 2026
Supports

Low-dose oral ketamine treatment was associated with improvements in depression, anxiety, stress, social functioning, suicidal ideation, and well-being in both MDD and MDD+PTSD groups, with no detectable difference in biological response between groups.

observational cohort Sample size: 35

MDMA-Enhanced Exposure Therapy Reverses PTSD-Like Features In a Learned Helplessness Mouse Model 2026
Supports

MDMA combined with exposure to a traumatic cue produced rapid and sustained recovery in trauma-susceptible mice, with significant treatment- and time-dependent effects on avoidance behavior.

preclinical study

The occurrence and potential role of mystical experiences in MDMA-assisted therapy for PTSD: A secondary analysis 2026
Mixed

MDMA sessions produced significantly higher mystical experience scores than placebo, and the Positive Mood subscale significantly mediated PTSD symptom reduction, while total and other subscale effects were non-significant.

secondary analysis of two phase 2 randomized trials Sample size: 53

Prevalence of Potential Contraindications and Risk Factors Relevant to MDMA-Assisted Therapy Among U.S. Veterans with Posttraumatic Stress Disorder 2026
Unclear

Each year, 15.3% to 17.3% of veterans with PTSD had at least one contraindication for MDMA-assisted therapy, 55.2% to 58.2% had at least one conditional or modifiable risk factor, and 85.7% to 87.5% filled a prescription for a potentially interacting medication.

serial cross-sectional study

Safety, feasibility, and preliminary clinical outcomes of psilocybin-assisted therapy for veterans with severe, treatment-resistant PTSD: an open-label pilot clinical trial. 2026
Supports

Psilocybin-assisted therapy was safe and well-tolerated in Veterans with severe treatment-resistant PTSD, with no serious adverse events or increased suicidal ideation, and clinician-rated PTSD symptoms decreased by a mean of 27.5 points from baseline to one-month follow-up.

open-label pilot trial Sample size: 12

MDMA as an early post-trauma intervention in a translational animal model of PTSD. 2026
Supports

MDMA at 10 mg/kg, administered 30 minutes after predator scent stress or 24 hours later with trauma-cue pairing, reduced anxiety-like behavior, startle amplitude, contextual freezing, and extreme behavioral responses, whereas lower doses and unpaired delayed administration were ineffective.

controlled animal study Sample size: 175

Silence is golden: Documenting the speech production of participants and support providers in psilocybin administration sessions for the treatment of post-traumatic stress disorder 2026
Unclear

During psilocybin administration sessions, 78% of time was filled with silence, and support was minimally enacted but experientially salient.

randomized controlled trial Sample size: 22

Points of agreement

  • MDMA-assisted therapy consistently reduces PTSD symptoms compared to placebo or active control across multiple randomized trials.
  • Ketamine infusions (single and repeated) produce rapid and significant reductions in PTSD symptom severity compared to active placebo.
  • Psychedelic-assisted therapies (MDMA, psilocybin) are generally safe and well-tolerated in clinical trials, with no serious adverse events reported.
  • Non-drug interventions such as mindfulness-based cognitive therapy and digital nonattachment programs also show significant PTSD symptom reductions.

Conflicts

  • One pilot study found no statistically significant clinician-rated CAPS reductions with MDMA-assisted psychotherapy, while other trials found significant effects.
  • The role of mystical experiences in MDMA-assisted therapy is debated: one secondary analysis found only the Positive Mood subscale mediated symptom reduction, not total mystical experience scores.
  • Animal studies show MDMA's preventive effects are dose-dependent and require trauma-cue pairing, whereas clinical trials do not report such nuances.

Gaps

  • Long-term durability of treatment effects beyond one year is rarely assessed.
  • Blinding is difficult in psychedelic trials due to subjective effects, potentially biasing results.
  • Most trials have small sample sizes and lack diverse populations.
  • Safety and efficacy in real-world settings with comorbid conditions and interacting medications are not fully established.
  • Optimal dosing, session number, and integration protocols remain to be determined.
  • Comparative effectiveness against established first-line treatments is not directly studied.
Browse these studies in the library
How we analyze this

This synthesis reads the 15 most-cited and 10 most recent studies whose primary subject is PTSD, up to 25 in all. The most-cited set anchors the established evidence, and the recent set surfaces work that is too new to have gathered citations yet.

A study qualifies only when PTSD or a known alias appears in its title or keywords, so broad reviews that mention it only in passing are left out. Each study is read from its abstract, strongest evidence first, and the summary reports the direction of the results along with any conflicts and gaps.

Ask your own question in the Research Synthesis Tool

Latest monthly recap: July 2026 →

1,578 articles · 670 from the last two years · 685,258 participants across 610 studies reporting sample size

Common study designs

review 383 systematic review 84 observational cohort 58 randomized controlled trial 98 theoretical or philosophical paper 133

Research

Synthesize the evidence → Search all →

MDMA-Assisted Therapy May Decrease PTSD Symptoms, Dissociation, Depression, and Functional Disability: A Systematic Review and Meta-Analysis

Harvard Review of Psychiatry September 8, 2026 Warwick M. Green, Sanket B Raut, F. E. James et al.

There is a need for new effective treatment options for posttraumatic stress disorder (PTSD), as many people with PTSD do not fully recover despite current treatments. 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy (MDMA-AT) is emerging as a new treatment option. We assessed the current body of MDMA-AT evidence for effectiveness in treating PTSD, associated impairments, and...

DOI: 10.1097/hrp.0000000000000478 (opens in new tab)

717. Clinical trials, ethical dimensions, and the pathway of MDMA-assisted therapy in PTSD

The International Journal of Neuropsychopharmacology September 1, 2026 Christopher Poppe, Dimitris Repantis

Abstract Background MDMA-assisted therapy (MDMA-AT) has shown promise for treatment-resistant post-traumatic stress disorder (PTSD), leveraging unique affective effects such as enhanced trust, empathy, and social connectedness. Despite preliminary efficacy, ethical challenges in clinical trials may directly affect regulatory approval and future clinical implementation. Aims & Objectives The...

DOI: 10.1093/ijnp/pyag040.489 (opens in new tab)

Efficacy of a Digital Nonattachment-Based Intervention for Post-traumatic Stress Symptoms: A Randomised Controlled Trial

Mindfulness September 1, 2026 Lindsay Tremblay, William van Gordon, James Elander

Abstract Objectives Nonattachment, defined as the capacity to relate to internal experiences, identities, and external circumstances without clinging, avoidance, or over-identification, has been associated with reduced psychological distress and enhanced well-being, yet its deliberate cultivation within trauma-focused interventions remains underexplored. This study evaluated Nonattachment for...

DOI: 10.1007/s12671-026-02872-0 (opens in new tab)

PSYCHEDELICS IN THE TREATMENT OF POST-TRAUMATIC STRESS DISORDER AND DEPRESSION: A REVIEW OF CLINICAL TRIALS

International Journal of Innovative Technologies in Social Science August 31, 2026 Anna Szeszko, Weronika Maria Czernek, Magdalena Cichorzewska et al.

Psychedelic-assisted therapy has emerged as a prominent area for psychiatric investigation particularly with regards to treatment-resistant depression and Post Traumatic Stress Disorder (PTSD). The purpose of this narrative review was to outline the current body of research regarding psychedelic and psychedelic-like compounds in these two psychiatric conditions highlighting psilocybin-assisted...

DOI: 10.31435/ijitss.3(51).2026.6062 (opens in new tab)

An Embodied Model of Trauma Recovery: Examining Internal Regulatory Processes and Racial Stress in PTSD Among Black Americans

August 21, 2026 Ashanti Brown

Black adults in the United States navigate profound and often invisible stressors at the intersection of racism and trauma. The burden of chronic racial stress functions as an embodied form of oppression that may increase the risk and intensity of post-traumatic stress disorder (PTSD) symptoms and undermine psychological strengths such as mindfulness and self-compassion for healing, recovery,...

DOI: 10.57709/451 (opens in new tab)

Blood biomarker changes in response to low-dose oral ketamine treatment in adults with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD)

medRxiv August 14, 2026 Annette M Braxton, Christina Driver, Daniel F. Hermens et al. preprint

Abstract Major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) are prevalent, chronic, and disabling mental health conditions which are difficult to treat. Ketamine has demonstrated effect for improving depression and PTSD symptoms independently but reports often overlook focused comorbid improvement of these symptoms within individuals. To address this, we assessed...

DOI: 10.64898/2026.08.12.26360216 (opens in new tab) Full text (opens in new tab)

MDMA-Enhanced Exposure Therapy Reverses PTSD-Like Features In a Learned Helplessness Mouse Model

bioRxiv (Cold Spring Harbor Laboratory) August 12, 2026 Orr Shahar, Perettz Golding, Masha Chaykin et al. preprint

Abstract Post-traumatic stress disorder (PTSD) is a highly prevalent, debilitating psychiatric condition. Existing treatments are ineffective for many patients. 3,4- methylenedioxymethamphetamine (MDMA)-assisted psychotherapy has demonstrated substantial clinical efficacy but relies on prolonged, resource-intensive therapeutic protocols that limit scalability and accessibility. Here, we...

DOI: 10.64898/2026.08.06.743271 (opens in new tab) Full text (opens in new tab)

The occurrence and potential role of mystical experiences in MDMA-assisted therapy for PTSD: A secondary analysis

Journal of Psychopharmacology August 6, 2026 Tijmen Bostoen, Erwin Krediet, Annette van Schagen et al.

Background: The potential safety and efficacy of the psychedelic 3,4-methylenedioxymethamphetamine-assisted therapy (MDMA-AT) for post-traumatic stress disorder (PTSD) has been researched in phase 2 and phase 3 clinical trials. We examined the occurrence and role of mystical experiences in MDMA-AT. Methods: Data were sourced from two phase 2 randomized trials of MDMA-AT for chronic PTSD, in...

DOI: 10.1177/02698811261464502 (opens in new tab)

Clinical trials

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