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PTSD research: what the evidence shows

(Post-traumatic stress disorder) A central target for MDMA-assisted therapy and related trauma-focused interventions.

State of the evidence

Synthesized

Synthesized from 22 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.

The research on PTSD is dominated by trials of MDMA-assisted psychotherapy, which consistently outperforms placebo or low-dose controls on clinician-rated PTSD symptoms, with large effects (roughly d = 0.7-0.9 in phase 3 trials) and gains that appear to persist for months to years in follow-up. Ketamine also shows rapid symptom reduction versus an active placebo, and mindfulness-based approaches show promise in smaller studies. The main caveats are small samples in several trials, difficulty blinding psychedelic studies, a common sponsor across MDMA trials, and limited long-term and diverse-population data.

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 22 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.
Study Design Sample size Direction Finding
MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study. 2021 RCT 90 Supports MDMA-assisted therapy produced significantly greater reductions in PTSD symptoms (d = 0.91) and functional impairment (d = 0.43) than placebo with therapy, with no serious adverse events.
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 RCT 20 Supports MDMA-assisted psychotherapy produced significantly greater CAPS reductions than placebo at all post-baseline time points, with 83% versus 25% clinical response and no drug-related serious adverse events.
Efficacy of Intravenous Ketamine for Treatment of Chronic Posttraumatic Stress Disorder 2014 RCT (crossover) 41 Supports A single ketamine infusion produced a significant and rapid reduction in PTSD symptom severity at 24 hours compared with midazolam.
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 RCT (dose-response) 26 Supports Active MDMA doses (75 mg and 125 mg) with psychotherapy produced large CAPS-IV reductions versus a 30 mg control, and symptoms remained reduced at 12 months after open-label full-dose MDMA.
A randomized, controlled pilot study of MDMA (±3,4-Methylenedioxymethamphetamine)-assisted psychotherapy for treatment of resistant, chronic Post-Traumatic Stress Disorder (PTSD) 2012 RCT 12 Mixed Full-dose MDMA-assisted psychotherapy produced significant self-reported improvement (PDS) but clinician-rated CAPS reductions did not reach significance (p = 0.066), with no drug-related serious adverse events.
MDMA-assisted therapy for moderate to severe PTSD: a randomized, placebo-controlled phase 3 trial. 2023 RCT 104 Supports MDMA-assisted therapy reduced CAPS-5 symptoms (d = 0.7) and functional impairment (d = 0.4) more than placebo with therapy, with no deaths or serious treatment-emergent adverse events.
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 long-term follow-up 19 Supports Gains from MDMA-assisted psychotherapy were maintained over a mean 45.4 months with no statistical difference from study exit scores, though two participants relapsed.
Theorizing that Psychedelic Assisted Therapy May Play a Role in the Treatment of Trauma-Induced Personality Disorders. 2024 theoretical Unclear Argues that borderline personality disorder and PTSD share neurobiological mechanisms and that psychedelic-assisted therapy may be a pathway for treating both.
Reviewing the Potential of Psychedelics for the Treatment of PTSD 2020 review Supports Argues that MDMA, ketamine, classical psychedelics, and cannabinoids each offer distinct therapeutic promise for PTSD, while outlining an agenda for future research.
A PILOT STUDY OF GROUP MINDFULNESS-BASED COGNITIVE THERAPY (MBCT) FOR COMBAT VETERANS WITH POSTTRAUMATIC STRESS DISORDER (PTSD) 2013 quasi-experimental 37 Supports Group mindfulness-based cognitive therapy produced significant and clinically meaningful PTSD symptom reductions compared with treatment-as-usual.
A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder. 2021 RCT 30 Supports Six ketamine infusions significantly reduced CAPS-5 and depression scores versus midazolam at two weeks, with a large effect size and a 67% responder rate.
Novel psychopharmacological therapies for psychiatric disorders: psilocybin and MDMA. 2016 review Supports Argues that psilocybin and MDMA show promise as adjuncts to psychotherapy for difficult-to-treat conditions, including refractory PTSD.
Multi-center, randomized controlled efficacy and comparative-effectiveness study evaluating ketamine, stellate ganglion blocks, combination treatment, and sham treatments for posttraumatic stress disorder and traumatic brain injury-associated headache: a study protocol 2026 RCT protocol 210 Unclear Describes a planned trial comparing ketamine, stellate ganglion blocks, and their combination against placebo/sham, noting that prior trial results are conflicting.
Voided REM Sleep (V-REM): A Candidate Biomarker Linking Treatment-Resistant PTSD and Major Depressive Disorder 2026 theoretical Unclear Proposes 'voided REM sleep' as a candidate biomarker of treatment-resistant PTSD and depression, with a falsifiable fMRI protocol to test it.
Recommending Meditation in Complex PTSD: Clinical Considerations 2026 review Unclear Argues that complex PTSD features such as dissociation and childhood adversity raise meditation-related adverse-event risk, so standard PTSD screening may miss patients needing enhanced informed consent.
Mindfulness and Posttraumatic Stress Symptoms in Mothers of Children With Pediatric Cancer 2026 cross-sectional survey 53 Supports Higher mindfulness was associated with lower posttraumatic stress symptoms, with acting with awareness and non-judgment each linked to lower symptoms.
The Nova Protocol: a comprehensive multimodal longitudinal study among civilian survivors of a mass trauma event. 2026 observational protocol Unclear Describes a longitudinal multimodal study of trauma survivors intended to characterize mechanisms and trajectories of PTSD symptoms, with naturalistic substance exposure treated as non-causal.
[The use of psychedelics in psychiatry]. 2026 review Mixed Argues that MDMA-assisted psychotherapy has the largest phase 3 PTSD dataset but was declined FDA approval in 2024 on ethical grounds, and that certainty of evidence remains low or very low for several indications.
A Systematic Review of MDMA’s Effects on Social Cognition in Placebo-Controlled Trials 2026 systematic review 75 Mixed MDMA consistently enhanced subjective social experience but behavioral prosociality was inconsistent, and it reduced accuracy in identifying negative social cues.
MDMA-Assisted Therapy May Decrease PTSD Symptoms, Dissociation, Depression, and Functional Disability: A Systematic Review and Meta-Analysis 2026 systematic review and meta-analysis Supports Across seven RCTs, MDMA-assisted psychotherapy may significantly improve PTSD symptoms, dissociation, depression, and functional impairment but not sleep quality, with evidence limited by small samples, blinding challenges, and a common sponsor.
Healing together: Results from a pilot trial of 3,4-Methylenedioxymethamphetamine-enhanced cognitive-behavioral conjoint therapy for posttraumatic stress disorder. 2026 pilot trial Supports MDMA-enhanced cognitive-behavioral conjoint therapy was feasible and acceptable and was associated with clinically meaningful PTSD symptom reductions and improved relationship satisfaction.
717. Clinical trials, ethical dimensions, and the pathway of MDMA-assisted therapy in PTSD 2026 literature review Unclear Argues that MDMA-assisted therapy trials raise distinctive ethical issues around vulnerability, memory and belief change, and informed consent that require systematic attention.

Points of agreement

  • Multiple RCTs and a meta-analysis find MDMA-assisted psychotherapy reduces PTSD symptoms more than placebo or low-dose controls, with large effect sizes.
  • MDMA trials report no drug-related serious adverse events or deaths.
  • Ketamine trials show rapid PTSD symptom reduction versus an active placebo.
  • Long-term follow-up suggests MDMA-assisted gains can persist for months to years.
  • Mindfulness-based and mindfulness-association studies link greater mindfulness to lower PTSD symptoms.

Conflicts

  • One small MDMA pilot found significant self-reported but not clinician-rated improvement, while larger trials found significant clinician-rated effects.
  • A review notes conflicting prior ketamine and stellate ganglion block trial results.
  • A review argues overall certainty of evidence remains low despite positive trials, and FDA declined MDMA approval on ethical grounds.

Gaps

  • Small sample sizes in several trials and pilot studies.
  • Blinding is difficult in psychedelic trials, and all MDMA trials share a common sponsor.
  • Therapies are non-standardized across trials.
  • Long-term durability data are limited to small follow-up samples.
  • Limited data in diverse populations and on complex PTSD, dissociation, and meditation-related adverse events.
  • Ketamine and combination-treatment comparative effectiveness is still being tested.
Browse these studies in the library

Common questions

What does the research agree on about PTSD?
  • Multiple RCTs and a meta-analysis find MDMA-assisted psychotherapy reduces PTSD symptoms more than placebo or low-dose controls, with large effect sizes.
  • MDMA trials report no drug-related serious adverse events or deaths.
  • Ketamine trials show rapid PTSD symptom reduction versus an active placebo.
  • Long-term follow-up suggests MDMA-assisted gains can persist for months to years.
  • Mindfulness-based and mindfulness-association studies link greater mindfulness to lower PTSD symptoms.
Where do studies on PTSD conflict?
  • One small MDMA pilot found significant self-reported but not clinician-rated improvement, while larger trials found significant clinician-rated effects.
  • A review notes conflicting prior ketamine and stellate ganglion block trial results.
  • A review argues overall certainty of evidence remains low despite positive trials, and FDA declined MDMA approval on ethical grounds.
What is still unknown about PTSD?
  • Small sample sizes in several trials and pilot studies.
  • Blinding is difficult in psychedelic trials, and all MDMA trials share a common sponsor.
  • Therapies are non-standardized across trials.
  • Long-term durability data are limited to small follow-up samples.
  • Limited data in diverse populations and on complex PTSD, dissociation, and meditation-related adverse events.
  • Ketamine and combination-treatment comparative effectiveness is still being tested.
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.

The full method, including what a person does and does not review, is on the methods page.

Ask your own question in the Research Synthesis Tool

Latest monthly recap: September 2026 →

2,096 articles · 738 from the last two years · 1,024,810 participants across 908 studies reporting sample size

Common study designs

review 439 systematic review 105 observational cohort 62 randomized controlled trial 128 theoretical or philosophical paper 167

Compounds studied for PTSD

Data updated

Studies whose primary subject is both the compound and PTSD, with reviews counted by the study design extracted from each abstract. Registered trials are from ClinicalTrials.gov, and each count links to that compound's full trial pipeline. This maps how much research exists, not how well anything works.

Compounds studied for PTSD: studies, meta-analyses and systematic reviews, registered clinical trials, the highest trial phase, and studies from the last two years. Most studies first.
Compound Studies Meta-analyses and systematic reviews Registered trials Highest phase From the last two years
MDMA 202 studies 22 meta-analyses and systematic reviews 50 registered trials up to Phase 3 61 from the last two years
Ketamine 129 studies 14 meta-analyses and systematic reviews 39 registered trials up to Phase 4 66 from the last two years
Psilocybin 48 studies 4 meta-analyses and systematic reviews 25 registered trials up to Phase 3 20 from the last two years

Research volume by year

Compare topics →

827 studies whose primary subject is PTSD since 2002

Studies about PTSD per year, 2002 to 2026, peaking at 119 in 2026 Bar chart: one bar per year, taller where more studies were published that year. 0 100 200 2005 2010 2015 2020 2025
2026 is partial
Show the numbers
Studies about PTSD per year, 2002 to 2026, peaking at 119 in 2026
Year Studies
2002 3
2003 1
2004 2
2005 2
2006 1
2007 5
2008 4
2009 2
2010 6
2011 9
2012 7
2013 11
2014 16
2015 15
2016 22
2017 34
2018 53
2019 33
2020 37
2021 58
2022 87
2023 87
2024 95
2025 118
2026 119

Research

Synthesize the evidence → Search all →

Impact of Mindfulness Training on PTSD Symptoms and Sleep Quality in a Cohort of Firefighters

Journal of Sleep Sciences October 26, 2026 Masoumeh Mansouri, Ali Naseri

Introduction: Firefighters are frequently exposed to traumatic occupational experiences, which may adversely affect their mental health and sleep quality. This study aimed to investigate the effect of a mindfulness-based intervention on post-traumatic stress disorder (PTSD) symptoms and sleep quality among firefighters in Shiraz, Iran. Methods: This quasi-experimental study employed a pre-test,...

DOI: 10.18502/jss.v9i1_2.23045 (opens in new tab)

Clinical and neurophysiological effects of imagery rehearsal therapy and targeted memory reactivation in post-traumatic stress disorder

Research Square October 14, 2026 Océane Lüthi, Vincent Rochas, Audrey Theux et al. preprint

Abstract Post-traumatic stress disorder is frequently associated with post-traumatic nightmares, which may be related to cortical hyperarousal. Imagery Rehearsal Therapy is the first-line treatment for nightmares. Targeted Memory Reactivation, which reactivates specific memories during sleep to enhance memory consolidation, has been shown to enhance the effects of Imagery Rehearsal Therapy in...

DOI: 10.21203/rs.3.rs-11359503/v1 (opens in new tab) Full text (opens in new tab)

Efficacy and safety of ketamine for post‐traumatic stress disorder: A systematic review with narrative synthesis and consideration of military and veteran populations

Psychiatry and Clinical Neurosciences Reports October 7, 2026 Mary Ivasyutyn, Saajan Bhakta

Abstract Post‐traumatic stress disorder (PTSD) is a debilitating disorder with limited pharmaceutical treatment options. Ketamine, a noncompetitive N ‐methyl‐ d ‐aspartate (NMDA) receptor antagonist with rapid‐onset effects, has emerged as a potential treatment, particularly for patients who do not respond to first‐line therapies. This systematic review synthesizes the current evidence on the...

DOI: 10.1002/pcn5.70425 (opens in new tab)

Enhancing interoceptive awareness in veterans with PTSD through Mind-Body Therapy in Denmark: A mixed-methods study

European Journal of Trauma & Dissociation October 1, 2026 Nanna Ahlmark, Lisa Suvarna Oldrup, Henrik Steen Andersen et al.

Background Veterans returning from military missions face an elevated risk of developing post-traumatic stress disorder (PTSD). Although some treatments are effective, many veterans experience limited benefit. Interoceptive awareness may play a particularly important role in PTSD, yet there is little understanding of whether—and how—measurable increases in interoceptive awareness are reflected...

DOI: 10.1016/j.ejtd.2026.100775 (opens in new tab)

Multi-center, randomized controlled efficacy and comparative-effectiveness study evaluating ketamine, stellate ganglion blocks, combination treatment, and sham treatments for posttraumatic stress disorder and traumatic brain injury-associated headache: a study protocol

Pain Management October 1, 2026 Steven Paul Cohen, Roman Smolynets, Jordan Wood et al.

BACKGROUND: Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) are conditions that share common mechanisms and are highly co-prevalent with each other and chronic pain. This pragmatic study will compare ketamine infusions to stellate ganglion blocks (SGB), their combination, and a placebo-sham-controlled arm. METHODS: A double-blind study conducted at 3 U.S. and Ukrainian...

DOI: 10.1080/17581869.2026.2738419 (opens in new tab)

Voided REM Sleep (V-REM): A Candidate Biomarker Linking Treatment-Resistant PTSD and Major Depressive Disorder

Preprints.org September 29, 2026 Mouhammad Ousmane Ndiaye preprint

A substantial proportion of patients with posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) do not respond to first-line treatment. Approximately 40% of PTSD patients do not respond to first-line psychotherapy, and 30.9% of MDD patients meet criteria for treatment-resistant depression. Yet standard polysomnography in these patients frequently shows REM sleep that appears...

DOI: 10.20944/preprints202609.2452.v1 (opens in new tab)

Recommending Meditation in Complex PTSD: Clinical Considerations

Journal of the American Psychiatric Nurses Association September 23, 2026 Jennifer Tustison

Objective: Posttraumatic stress disorder (PTSD) guidelines are often applied to complex PTSD (CPTSD), despite CPTSD’s distinct symptomatology. Core CPTSD symptoms, including affect dysregulation, negative self-concept, and relational disruption, may substantially alter treatment needs and safety considerations for mindfulness-based interventions. This article discusses clinical considerations...

DOI: 10.1177/10783903261488383 (opens in new tab)

Mindfulness and Posttraumatic Stress Symptoms in Mothers of Children With Pediatric Cancer

Clinical Practice in Pediatric Psychology September 17, 2026 Erinne R. Benedict, Hannah-Rose Mitchell

Background: Mothers are often identified as the primary caregiver, thus at unique risk for psychological sequelae of their child’s cancer, including elevated posttraumatic stress symptoms (PTSS). Studies have shown greater mindfulness is often associated with lower PTSS across populations. Methods: The current study examined associations between mothers’ mindfulness and its specific domains and...

DOI: 10.1177/21694826261484571 (opens in new tab)

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)

Clinical trials

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