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Psychedelic-assisted therapy research: what the evidence shows

The clinical model pairing a psychedelic session with structured psychological support.

State of the evidence

Synthesized

Synthesized from 24 studies in the library · AI-generated, grounded in the abstracts below

Found by searching the library for Psychedelic-assisted therapy, psychedelic therapy, assisted psychotherapy, psychedelic-assisted psychotherapy, then ranked by relevance.

The research on psychedelic-assisted therapy is mostly early-stage but points in a positive direction: small randomized trials and open-label studies report large reductions in depression, anxiety, and PTSD symptoms after psilocybin, LSD, or MDMA given with psychological support, and several show benefits persisting for months to a year. Results are broadly consistent across substances and conditions, but samples are very small, most trials are unblinded or use active placebos, and the psychological therapy component is highly heterogeneous, so efficacy cannot yet be firmly established. The main caveats are small sample sizes, limited durability data, and uncertainty about how much of the benefit comes from the drug versus the therapy context.

Evidence by study

Direction is which way each study's own result points, not our rating of the study.

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
Psilocybin with psychological support for treatment-resistant depression: six-month follow-up. 2017 open-label trial 20 Supports Two psilocybin doses produced large reductions in depressive symptoms (Cohen's d 2.2 at week 1) that remained significant at 6 months.
Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. 2011 randomized controlled trial 18 Supports High doses of psilocybin occasioned mystical-type experiences and were rated as producing sustained positive changes in attitudes, mood, and behavior, undiminished at 14 months.
Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases 2014 randomized controlled trial 12 Supports LSD-assisted psychotherapy reduced trait and state anxiety at 2 months with large effect sizes, sustained for 12 months, with no serious adverse events.
The Therapeutic Potential of Psychedelic Drugs: Past, Present, and Future. 2017 commentary Unclear Argues that renewed psychedelic research, especially psilocybin for depression, holds promise but faces pitfalls.
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 randomized controlled trial 20 Supports MDMA-assisted psychotherapy produced significantly greater reductions in PTSD symptom scores than placebo, with 83% versus 25% clinical response and no drug-related serious adverse events.
Percentage of Heavy Drinking Days Following Psilocybin-Assisted Psychotherapy vs Placebo in the Treatment of Adult Patients With Alcohol Use Disorder 2022 randomized controlled trial 95 Supports Psilocybin plus psychotherapy led to 9.7% heavy drinking days versus 23.6% with active placebo plus psychotherapy over 32 weeks.
Patients’ Accounts of Increased “Connectedness” and “Acceptance” After Psilocybin for Treatment-Resistant Depression 2017 qualitative study 20 Supports Patients described psilocybin treatment as fostering connection and emotional acceptance, in contrast to conventional treatments they felt reinforced disconnection and avoidance.
The Subjective Effects of Psychedelics Are Necessary for Their Enduring Therapeutic Effects. 2020 review Supports Argues that the subjective effects of psychedelics are necessary for their enduring therapeutic benefits and account for most of those benefits.
LSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects 2014 prospective follow-up with qualitative content analysis 10 Supports Anxiety reductions were sustained over 12 months, with no lasting adverse reactions and reports of insightful, cathartic experiences.
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 randomized, double-blind, dose-response phase 2 trial 26 Supports Active MDMA doses produced large reductions in PTSD symptom severity versus a low-dose control, with symptoms still reduced at 12 months after open-label dosing.
Increased global integration in the brain after psilocybin therapy for depression. 2022 open-label trial and double-blind phase II RCT Supports Antidepressant response to psilocybin was rapid and sustained and correlated with decreased brain network modularity, while the escitalopram response was milder.
A randomized, controlled pilot study of MDMA (±3,4-Methylenedioxymethamphetamine)-assisted psychotherapy for treatment of resistant, chronic Post-Traumatic Stress Disorder (PTSD) 2012 randomized controlled trial 12 Mixed MDMA-assisted psychotherapy produced significant self-reported PTSD improvement but clinician-rated reductions were not statistically significant (p = 0.066).
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 of a completed trial 19 Supports Gains in PTSD symptom relief were maintained over an average of 45 months, with two relapses and no reported harm or drug dependency.
Psychological flexibility mediates the relations between acute psychedelic effects and subjective decreases in depression and anxiety. 2020 cross-sectional survey 985 Supports Acute mystical and insightful effects were associated with decreases in depression and anxiety, fully mediated by increases in psychological flexibility.
Embodied Transformation: Psychedelic Therapy Through the Lens of Merleau-Ponty’s Phenomenology 2026 theoretical Unclear Argues that psychedelic mystical experience recalibrates the intentional arc and restores pre-reflective meaning, framing depression as a collapse of perceptual attunement.
Epistemic Discipline in Psychedelic-Assisted Therapy: Memory, Therapy Dynamics, Attachment Patterns, and Sexual Abuse 2026 theoretical Unclear Argues that psychedelic-assisted therapy carries foreseeable epistemic risks because noetic quality does not reliably indicate historical veridicality, and proposes epistemic discipline as a clinician obligation.
Longitudinal peripheral DNA methylation remodeling following ketamine-assisted psychotherapy in major depressive disorder 2026 longitudinal observational study 10 Supports Depressive symptoms declined markedly after ketamine-assisted psychotherapy, alongside exploratory DNA methylation changes that the authors say do not establish causality.
Aspirational Autonomy and Psychedelic-Assisted Therapy in Advanced Cancer: Ethical Lessons from Clinical Cases. 2026 commentary Unclear Argues that psychedelic-assisted therapy should be judged by whether it helps patients move toward valued self-understanding and connection, and proposes consent as endorsement of a supported aspirational process.
Ketamine administered biomedically or as psychedelic-assisted therapy in treatment-resistant depression: Differing efficacy based on depressive subtype or presence of childhood trauma? 2026 commentary Mixed Argues that ketamine efficacy may differ by depressive subtype, reporting preliminary open-label findings favoring biomedical ketamine in melancholic depression, and notes studies of ketamine as a psychedelic agent with psychotherapy are lacking.
Oral Ketamine-Assisted Psychotherapy Leading to Prolonged Remission in Recurrent Dissociative Neurological Symptom Disorder With Mutism: A Case Report 2026 case study 1 Supports After six sessions of oral ketamine-assisted psychotherapy the patient regained spontaneous speech sustained over a year, though the authors note this single case is hypothesis-generating.
A Social Justice Perspective on Psychedelic-Assisted Psychotherapy in Community Mental Health 2026 theoretical Unclear Argues that while emerging research indicates psychedelic-assisted psychotherapy is effective for depression and PTSD, inequities in research and implementation raise social justice concerns.
Beyond the substance: A systematic review of psychological treatment frameworks in psychedelic-assisted therapy 2026 systematic review 1537 Mixed Nearly all trials followed a preparation-dosing-integration structure, but psychological support was highly heterogeneous, complicating isolation of pharmacological from contextual effects.
Psilocybin-assisted psychotherapy for people with cancer: a scoping review of intervention components, psychotherapeutic frameworks, and models of delivery 2026 scoping review Unclear Maps the extent and types of evidence on psilocybin-assisted psychotherapy in cancer, including psychotherapy types, delivery models, and outcomes, without reporting results in the abstract.
Counselors’ Training Needs in Effectively Engaging With Psychedelic-Assisted Therapy 2026 exploratory sequential mixed-methods study Unclear Counselors identified 142 statements in 16 clusters reflecting needs to solidify their place in psychedelic-assisted therapy, develop evidence-based practice, and ensure specialized ongoing development.

Points of agreement

  • Multiple small trials across psilocybin, LSD, and MDMA report large symptom reductions in depression, anxiety, and PTSD when the drug is given with psychological support.
  • Several studies report benefits persisting for months to a year or more after treatment.
  • Acute subjective experiences (mystical, insightful) are repeatedly linked to therapeutic outcomes.
  • Serious adverse events are rarely reported in these supervised settings.

Conflicts

  • Clinician-rated PTSD improvement was not statistically significant in one MDMA trial, while self-reported improvement was, and other MDMA trials found significant clinician-rated effects.
  • Some work attributes benefit largely to subjective drug effects, while a systematic review finds psychological support so heterogeneous that pharmacological and contextual contributions cannot be separated.
  • Ketamine commentary suggests biomedical ketamine may outperform psychedelic-assisted use in some subtypes, contrasting with the broader positive framing of psychedelic-assisted therapy.

Gaps

  • Most trials are small and open-label or use active placebos, so blinding is limited.
  • Durability beyond 6-12 months is documented in only a few follow-up studies.
  • The psychological therapy component is highly variable and untested as an independent factor.
  • Populations studied are narrow; representation of diverse and community mental health groups is questioned.
  • Dose-response and optimal dosing remain incompletely characterized.
  • Ethical and epistemic risks, training needs, and consent frameworks are discussed but not empirically tested.
Browse these studies in the library

Common questions

What does the research agree on about psychedelic-assisted therapy?
  • Multiple small trials across psilocybin, LSD, and MDMA report large symptom reductions in depression, anxiety, and PTSD when the drug is given with psychological support.
  • Several studies report benefits persisting for months to a year or more after treatment.
  • Acute subjective experiences (mystical, insightful) are repeatedly linked to therapeutic outcomes.
  • Serious adverse events are rarely reported in these supervised settings.
Where do studies on psychedelic-assisted therapy conflict?
  • Clinician-rated PTSD improvement was not statistically significant in one MDMA trial, while self-reported improvement was, and other MDMA trials found significant clinician-rated effects.
  • Some work attributes benefit largely to subjective drug effects, while a systematic review finds psychological support so heterogeneous that pharmacological and contextual contributions cannot be separated.
  • Ketamine commentary suggests biomedical ketamine may outperform psychedelic-assisted use in some subtypes, contrasting with the broader positive framing of psychedelic-assisted therapy.
What is still unknown about psychedelic-assisted therapy?
  • Most trials are small and open-label or use active placebos, so blinding is limited.
  • Durability beyond 6-12 months is documented in only a few follow-up studies.
  • The psychological therapy component is highly variable and untested as an independent factor.
  • Populations studied are narrow; representation of diverse and community mental health groups is questioned.
  • Dose-response and optimal dosing remain incompletely characterized.
  • Ethical and epistemic risks, training needs, and consent frameworks are discussed but not empirically tested.
How we analyze this

This synthesis reads the 15 most-cited and 10 most recent studies whose primary subject is Psychedelic-assisted therapy, 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 Psychedelic-assisted therapy 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 →

2,926 articles · 1,289 from the last two years · 1,603,143 participants across 874 studies reporting sample size

Common study designs

review 665 qualitative study 123 systematic review 156 randomized controlled trial 94 theoretical or philosophical paper 488

Compounds in psychedelic-assisted therapy research

Data updated

Studies whose primary subject is both the compound and psychedelic-assisted therapy, 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 in psychedelic-assisted therapy research: 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
Psilocybin 250 studies 32 meta-analyses and systematic reviews 23 registered trials up to Phase 2 93 from the last two years
MDMA 148 studies 19 meta-analyses and systematic reviews 21 registered trials up to Phase 3 47 from the last two years
Ketamine 92 studies 14 meta-analyses and systematic reviews 16 registered trials up to Phase 4 47 from the last two years
LSD 55 studies 5 meta-analyses and systematic reviews 2 registered trials up to Phase 2 16 from the last two years

Research volume by year

Compare topics →

962 studies whose primary subject is psychedelic-assisted therapy since 2002

Studies about psychedelic-assisted therapy per year, 2002 to 2026, peaking at 219 in 2025 Bar chart: one bar per year, taller where more studies were published that year. 0 150 300 2005 2010 2015 2020 2025
2026 is partial
Show the numbers
Studies about psychedelic-assisted therapy per year, 2002 to 2026, peaking at 219 in 2025
Year Studies
2002 3
2003 0
2004 1
2005 1
2006 0
2007 2
2008 1
2009 0
2010 1
2011 1
2012 3
2013 1
2014 4
2015 1
2016 3
2017 12
2018 29
2019 18
2020 34
2021 55
2022 84
2023 140
2024 192
2025 219
2026 157

Research

Synthesize the evidence → Search all →

Psychedelic assisted psychotherapy (2020–2025): a scoping review of clinical evidence, mechanisms, safety, and ethics

Frontiers in Psychology October 27, 2026 Nasiru Mohammed Abdullahi, Rashid Menhas, Patience Osose Nasir et al.

Background: Clinical research on psychedelic-assisted therapy (PAT) has expanded substantially in recent years, particularly for post-traumatic stress disorder (PTSD) and depressive disorders. Contemporary studies have generally evaluated psychedelic administration within controlled therapeutic settings that include psychological support, preparation, and integration. However, variability in...

DOI: 10.3389/fpsyg.2026.1820860 (opens in new tab)

From Acute MDMA Experiences to Lasting Change: Self-Compassion’s Role in MDMA-Assisted Psychotherapy for Social Anxiety Disorder

October 25, 2026 Christina Chwyl, Mary K. Lear, Sunjeev K. Kamboj et al. preprint

Objectives: Self-compassion may benefit individuals with social anxiety disorder and serve as a mechanism of change within 3,4-Methylenedioxymethamphetamine (MDMA)-assisted therapy (MDMA-AT). Methods: In this secondary analysis of 20 adults with social anxiety disorder who underwent MDMA-AT for social anxiety disorder (NCT05138068), we examined whether both trait self-compassion changes across...

DOI: 10.31234/osf.io/3ard8_v1 (opens in new tab)

Longitudinal peripheral DNA methylation remodeling following ketamine-assisted psychotherapy in major depressive disorder

Epigenetics October 15, 2026 Arghavan Nepton, Sonya C. Faber, Zachary A. Kaminsky et al.

Ketamine produces rapid antidepressant effects, but the molecular processes associated with their persistence remain poorly defined in humans. We examined longitudinal DNA methylation changes in 10 adults with major depressive disorder undergoing ketamine-assisted psychotherapy using two pre-treatment assessments (T1, T2) and one post-treatment assessment (T3). Participants received three...

DOI: 10.1080/15592294.2026.2731659 (opens in new tab)

Aspirational Autonomy and Psychedelic-Assisted Therapy in Advanced Cancer: Ethical Lessons from Clinical Cases.

The oncologist October 15, 2026 Keenan Wills Davis, Michelle C. Bach, JoEllen Schimmels et al.

Psychedelic-assisted therapy (PAT) is increasingly discussed as a potential intervention for anxiety, depression, and existential distress among patients with advanced cancer. Yet the ethical challenges of PAT for patients approaching the end of life remain underdeveloped, particularly for oncologists who may be asked to counsel patients or consider referral to clinical trials. This article...

DOI: 10.1093/oncolo/oyag402 (opens in new tab) Full text (opens in new tab) Psychedelic-assisted therapy Ethics Informed consent Palliative oncology

Ketamine administered biomedically or as psychedelic-assisted therapy in treatment-resistant depression: Differing efficacy based on depressive subtype or presence of childhood trauma?

Australasian Psychiatry October 13, 2026 Adam Bayes, Colleen Loo

ObjectiveThe ideas presented in this paper are based on a presentation at a festschrift event marking the retirement of Professor Gordon Parker from UNSW, Sydney. Drawing on Gordon's depressive subtyping approach and his critiques of a unitary view of major depressive disorder and treatment-resistant depression (TRD), we aim to (i) explore differing models of ketamine for TRD - biomedical...

DOI: 10.1177/10398562261494440 (opens in new tab) Full text (opens in new tab)

Oral Ketamine-Assisted Psychotherapy Leading to Prolonged Remission in Recurrent Dissociative Neurological Symptom Disorder With Mutism: A Case Report

Cureus October 12, 2026 Anirudh Bakam

Dissociative neurological symptom disorder (DNSD), termed functional neurological symptom disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), presents with neurological symptoms not explained by structural disease.The first line treatment of DNSD is psychotherapy, but when the conflict maintaining the symptoms cannot be put into words,...

DOI: 10.7759/cureus.117827 (opens in new tab) Full text (opens in new tab)

A Social Justice Perspective on Psychedelic-Assisted Psychotherapy in Community Mental Health

Routledge eBooks October 9, 2026 Susan Cameron

Psychedelics have re-emerged in this century as a popular substance to use by people of different ages and socio-economic status. The reasons for use vary between recreational and treatment focused. The Controlled Substance Act of 1970, signed by then President Richard Nixon, created a ban on the use of these substances in the United States, but advocates have found reason to revisit the...

DOI: 10.4324/9781003566229-7 (opens in new tab)

Beyond the substance: A systematic review of psychological treatment frameworks in psychedelic-assisted therapy

Therapeutic Advances in Psychopharmacology October 8, 2026 Gianluca A. Florineth, Anna L. Boeker, Felix Müller et al.

Background Classic psychedelics show potential for treating psychiatric disorders, yet the psychological framework of psychedelic-assisted therapy (PAT) remains underspecified. As regulatory approval approaches, defining the contribution of psychological interventions to clinical outcomes is critical for both mechanism inference and implementation. Objectives To systematically review the...

DOI: 10.1177/20451253261492600 (opens in new tab) Full text (opens in new tab)

Psilocybin-assisted psychotherapy for people with cancer: a scoping review of intervention components, psychotherapeutic frameworks, and models of delivery

OSF Preprints October 7, 2026 Suzanne Grant, Maria González, Hannah Adler preprint

The objective of this scoping review is to map the extent, range, and types of evidence related to psilocybin-assisted psychotherapy in people with cancer, including the types of psychotherapy used, models of delivering therapy, and associated outcomes, as reported in qualitative and quantitative studies.

DOI: 10.17605/osf.io/hvwtm (opens in new tab)

Counselors’ Training Needs in Effectively Engaging With Psychedelic-Assisted Therapy

ODU Digital Commons October 6, 2026 Elif Bor

As public and scientific interest in psychedelic-assisted therapy (PAT) continues to grow, counselors are increasingly encountering clients who are exploring or engaging in psychedelic use for therapeutic purposes. Such encounters introduce new ethical, clinical, and professional considerations. Counselors must develop an informed understanding of psychedelics and their effects, recognize the...

DOI: 10.25777/zfy1-pt58 (opens in new tab) Full text (opens in new tab)

Clinical trials

All Psychedelic-assisted therapy trials →