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Psychedelic-assisted therapy

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

State of the evidence

Synthesized

Synthesized from 25 studies in the library · AI-generated, grounded in the abstracts below

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

Psychedelic-assisted therapy shows promise for conditions like depression, PTSD, anxiety, and alcohol use disorder, with several randomized controlled trials and open-label studies reporting large, rapid, and sometimes durable improvements. However, the evidence base remains limited by small sample sizes, open-label designs, and heterogeneity in protocols, so conclusions about efficacy are preliminary and require confirmation in larger, well-controlled trials.

Confidence in the evidence

Low-Moderate
  • Multiple RCTs (e.g., 16219, 16276, 19921) show positive effects, but sample sizes are small (12-103 participants per study).
  • Several key studies (e.g., 8534, 16028) are open-label, lacking blinding and control, increasing risk of bias.
  • Results are generally consistent in direction (positive) across different substances (psilocybin, LSD, MDMA, ketamine) and conditions, but heterogeneity in protocols limits comparability.
  • Long-term follow-up data (e.g., 8534, 16282, 19854) suggest durability, but are from small samples and often lack control groups.
How we rate confidence

Confidence reflects the strength of the underlying evidence, not whether the result is favorable. It weighs the number and size of studies, their design (randomized trials count for more than observational or single-case work), how consistently they point the same way, and their risk of bias.

Tiers run from Insufficient to High. High is rare in this field: small, early, or open-label studies land lower even when their direction is encouraging.

Evidence by study

Direction is each study's finding relative to your question: Supports, Opposes, No effect, Mixed, or Unclear.

Psilocybin with psychological support for treatment-resistant depression: six-month follow-up. 2017
Supports

Psilocybin with psychological support produced large reductions in depressive symptoms (Cohen's d = 2.2 at week 1, 2.3 at week 5) that remained significant at 6 months (d = 1.4).

open-label trial Sample size: 20

Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. 2011
Supports

Psilocybin at 20 and 30 mg/70 kg occasioned mystical-type experiences in 72% of volunteers, with persisting positive changes in attitudes, mood, and behavior at 14 months.

double-blind dose-effect study Sample size: 18

Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases 2014
Supports

LSD-assisted psychotherapy significantly reduced trait and state anxiety at 2 months (effect sizes 1.1 and 1.2), with reductions sustained for 12 months.

double-blind, randomized, active placebo-controlled pilot study Sample size: 12

The Therapeutic Potential of Psychedelic Drugs: Past, Present, and Future. 2017
Unclear

This review discusses the therapeutic potential of psychedelic drugs but does not provide specific quantitative findings.

review

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
Unclear

The abstract does not provide specific results, only the study description.

randomized controlled pilot study

Percentage of Heavy Drinking Days Following Psilocybin-Assisted Psychotherapy vs Placebo in the Treatment of Adult Patients With Alcohol Use Disorder 2022
Supports

Two administrations of high-dose psilocybin improved the percentage of heavy drinking days in patients with AUD undergoing psychotherapy compared to active placebo.

double-blind randomized clinical trial

Patients’ Accounts of Increased “Connectedness” and “Acceptance” After Psilocybin for Treatment-Resistant Depression 2017
Supports

Patients reported that psilocybin treatment promoted connection and acceptance, in contrast to conventional treatments which reinforced disconnection and avoidance.

qualitative thematic analysis Sample size: 20

The Subjective Effects of Psychedelics Are Necessary for Their Enduring Therapeutic Effects. 2020
Supports

The authors propose that the subjective effects of psychedelics are necessary for their enduring therapeutic benefits, accounting for the majority of benefit.

theoretical review

LSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects 2014
Supports

LSD-assisted psychotherapy led to sustained reductions in anxiety and improved quality of life at 12 months, with participants reporting insightful, cathartic, and interpersonal experiences.

qualitative content analysis with prospective follow-up Sample size: 10

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
Unclear

The abstract does not provide specific results, only the study description.

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

Increased global integration in the brain after psilocybin therapy for depression. 2022
Unclear

The abstract does not provide specific results, only the study description.

observational

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 did not show statistically significant reductions in clinician-rated CAPS scores (p = 0.066), but did show significant self-reported improvement on the PDS (p = 0.014).

randomized, double-blind, active-placebo controlled pilot study Sample size: 12

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

At a mean of 45.4 months follow-up, the majority of subjects maintained statistically and clinically significant gains in PTSD symptom relief from MDMA-assisted psychotherapy.

prospective long-term follow-up study Sample size: 19

Psychological flexibility mediates the relations between acute psychedelic effects and subjective decreases in depression and anxiety. 2020
Supports

Psychological flexibility fully mediated the effect of mystical and insightful experiences on decreases in depression and anxiety following a psychedelic experience.

cross-sectional survey study Sample size: 985

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. 2019
Supports

MDMA-assisted psychotherapy produced significantly greater reductions in CAPS-IV scores than control (between-group difference -22.0, p < 0.001, Cohen's d = 0.8), with 54.2% of the active group no longer meeting PTSD diagnostic criteria.

pooled analysis of six phase 2 randomized controlled trials Sample size: 103

Changes in trauma symptoms of discrimination after MDMA-assisted psychotherapy for posttraumatic stress disorder. 2026
Supports

MDMA-assisted therapy significantly reduced trauma symptoms of discrimination by 38% (Cohen's d = 1.28, p = .046), though the sample size was very small.

preliminary study Sample size: 5

Mystical Experiences as Catalysts in Ketamine-Assisted Psychotherapy: A Case Study 2026
Supports

Greater therapeutic gains in ketamine-assisted psychotherapy followed sessions with higher mystical-type experience scores, with the patient attributing improvements to the psychological and spiritual impact.

case study Sample size: 1

Making a case for using MDMA-assisted psychotherapy for borderline personality disorder and complex PTSD: a descriptive systematic review of the literature 2026
Supports

Most of the 24 included studies reported reduced PTSD symptoms post-intervention, with some noting decreased dissociative symptoms at higher MDMA doses.

descriptive systematic review Sample size: 335

Reframing distress in oncology: the potential of psychedelic-assisted therapy. 2026
Supports

Recent trials in advanced cancer populations report improvements in anxiety, depression, pain-related distress, and quality of life following one or two dosing sessions of psychedelic-assisted therapy.

review

The purpose of the psychosocial protocol in the psychedelic-assisted therapy: A scoping review 2026
Unclear

This review categorizes psychosocial protocols used in psychedelic research, noting limited reporting and heterogeneity as methodological challenges.

scoping review

Navigating ‘k-land’: a qualitative exploration of participants’ experiences of ketamine-assisted psychotherapy for methamphetamine use disorder 2026
Supports

Participants in ketamine-assisted psychotherapy for MAUD described reduced emotional and cognitive reactivity and translation of psychological shifts into behavioral change.

qualitative study embedded in open-label pilot trial Sample size: 14

Ketamine-assisted psychotherapy for posttraumatic stress disorder: a systematic review and individual participant data meta-analysis of predictors of treatment effects. 2026
Supports

Greater improvement in PTSD symptoms was associated with more psychotherapy sessions (β = 1.03 per session) and more ketamine sessions (β = 1.15 per session), but most included studies were of poor quality.

systematic review and individual participant data meta-analysis Sample size: 533

Music Playlist Use in Clinical Trials of Psychedelic Assisted Psychotherapy: A Systematic Review 2026
Unclear

There is considerable variation in music selection and use in psychedelic-assisted psychotherapy trials, with no standardized protocol.

systematic review

Integrating psychedelic-assisted psychotherapy into addiction care in the Czech Republic: Clinical evidence, safety, and regulatory developments 2026
Supports

The strongest direct evidence for psychedelic-assisted therapy in addiction treatment comes from a limited number of randomized and controlled studies, suggesting cautious clinical potential rather than established effectiveness.

narrative review

Attitudes and perceptions of psychedelic therapy among clinical trial participants with alcohol use disorder: a mixed-method study 2026
Supports

64.3% of participants were willing to participate in a psychedelic therapy trial, with willingness significantly associated with higher expectations of research success.

mixed-method study Sample size: 112

Points of agreement

  • Psychedelic-assisted therapy (with psilocybin, LSD, MDMA, and ketamine) is associated with large, rapid reductions in symptoms of depression, anxiety, and PTSD across multiple studies.
  • Subjective effects (e.g., mystical-type experiences, psychological flexibility) are consistently linked to therapeutic outcomes.
  • Improvements often persist for months to over a year after treatment, as shown in several follow-up studies.
  • The therapy is generally well-tolerated with no serious adverse events reported in the reviewed studies.

Conflicts

  • One pilot study (22029) found no significant clinician-rated improvement on the CAPS despite significant self-reported improvement, suggesting possible divergence between measures.
  • The quality of evidence varies widely, from open-label and qualitative studies to double-blind RCTs, leading to different levels of confidence in findings.

Gaps

  • Most studies have small sample sizes, limiting generalizability and statistical power.
  • There is a lack of large, multi-site phase 3 trials for most substances and conditions, though some are underway.
  • Heterogeneity in treatment protocols (dose, number of sessions, psychotherapy model, music use) makes cross-study comparisons difficult.
  • Long-term durability beyond 12 months is not well-established for most indications.
  • Few studies include diverse populations or examine effects on discrimination-related trauma, with most samples being predominantly white and male.
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 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.

Ask your own question in the Research Synthesis Tool

Latest monthly recap: June 2026 →

2,650 articles · 1,206 from the last two years · 1,575,552 participants across 784 studies reporting sample size

Common study designs

review 624 qualitative study 108 systematic review 141 randomized controlled trial 85 theoretical or philosophical paper 420

Research

Synthesize the evidence → Search all →

Simulated States of Consciousness: Inducing Psychedelic Experiences in Virtual Reality

Harman Brar

Virtual reality is used as a therapeutic tool for anxiety, PTSD, and depression through exposure therapy and simulated environments, but its potential to mimic psychedelic experiences has not been examined. Research suggests individuals in VR simulated psychedelic experiences undergo effects similar to those from psychedelic drugs, though the physiological impact on the brain and mind is largely unexplored. To determine whether VR can mimic psychedelics, targeting 5-HT receptor activity in the frontal lobe is proposed as a hypothesis. This paper examines drug mechanisms of psychedelics, the theoretical application of VR-based psychedelic therapy, and postulates a method to measure the effectiveness of psychedelic simulations for psychopathology.

DOI: 10.32920/23153678.v1

Associations between Hallucinogen Persisting Perception Disorder (HPPD) and non-visual perceptual disturbances

Anneliese McConnell, Wei He, Harry McConnell et al. preprint

People with Hallucinogen Persistent Perception Disorder (HPPD) are substantially more likely to also experience other perceptual disturbances, suggesting a shared underlying vulnerability. In a survey of 138 individuals with HPPD and 116 controls, HPPD was strongly associated with photosensitivity (odds ratio 10.65) and phonosensitivity (odds ratio 8.00), and with a greater number of perceptual disturbances overall. Trends also linked HPPD to tinnitus, migraine with aura, vertigo, paraesthesia, and synaesthesia. Those with both HPPD and other perceptual disturbances were more likely to develop additional disturbances after HPPD onset. These findings highlight potential risk factors for HPPD, relevant as psychedelic therapies become more common.

DOI: 10.31234/osf.io/xeg96

Evidence-Based Medicine is inadequate to develop evidence-based psychedelic therapies.

Eduardo Ekman Schenberg preprint

Between April and October 2024, expert bodies in the US and the Netherlands reached opposite conclusions on MDMA for PTSD. The FDA rejected Lykos Therapeutics' New Drug Application despite prior breakthrough therapy status, while the Dutch State Commission recommended making the treatment available as soon as possible. These contrasting decisions highlight epistemic differences in evidence assessment: the FDA's approach aligned with traditional Evidence-Based Medicine (EBM), whereas the Dutch approach resembled the newer EBM+ framework. Drawing on historical fatal examples and recent evidence-assessment debates (e.g., masking during COVID-19), the authors argue that shifting to EBM+ is essential for reliable assessments of psychedelic therapies.

DOI: 10.31234/osf.io/rzdpm

Binaries, Multitudes, and Beyond: A Client-Authored Case Study in Psychedelic-Assisted Therapy, Artificial Intelligence, and Narrative Agency

Mark A. Michaels

A client who is also the author documents a 10-week course of collaborative therapy that integrates EMDR, ketamine, MDMA, psilocybin, creative expression, and AI-assisted reflection and writing. Drawing on affect theory, mentalization, earned secure attachment, and Dabrowski's theory of positive disintegration, the paper analyzes how recognition of core affects, rupture-and-repair processes, and the reclamation of narrative agency contributed to rapid, positive change. Psychoeducation supported a deep exploration of these concepts. The case critiques traditional psychoanalytic framings, diagnostic overreach, and hierarchical therapeutic structures, arguing for a model emphasizing collaboration, agency, and narrative coherence. It also highlights the potential and limitations of generative AI as an adjunct in psychotherapy and narrative self-reclamation.

DOI: 10.2139/ssrn.6317678

Malpractice without a Baseline: Tort Liability and the Structural Paradoxes of Psychedelic-assisted Therapy

Michael Palmieri

Psychedelic-assisted therapy is moving toward clinical legitimacy in the United States, with the FDA granting Breakthrough Therapy designations to psilocybin and MDMA and major research investments underway. However, the legal framework for malpractice liability in this field remains undeveloped. The article identifies three structural challenges: the standard of care is unclear because the profession lacks settled credentialing and practice standards; causation analysis is complicated when treatment intentionally alters a patient's evaluative framework; and damages calculations face a paradox when identity transformation may later be viewed as beneficial. The article argues these are permanent structural features, not transitional problems, and proposes doctrinal adaptations such as prospective consent architectures and tiered standard-of-care frameworks.

DOI: 10.2139/ssrn.6383498

Consent Without Continuity: Psychedelic-Assisted Therapy and the Structural Failure of Informed Consent Doctrine

Michael Palmieri

American informed consent law assumes that a patient's values and decision-making framework remain stable from the moment they authorize a treatment through the period when they experience its effects. Psychedelic-assisted therapy, using compounds like psilocybin and MDMA, deliberately alters patients' values, self-concept, and evaluative frameworks as a therapeutic goal, breaking that continuity. This article argues that when a treatment transforms the cognitive architecture through which risk is assessed, standard consent doctrines—materiality, causation, and capacity—fail. The author proposes a dynamic consent model with pre-session identity-impact disclosures, staged reaffirmation checkpoints, integration-phase consent validation, and longitudinal documentation reforms.

DOI: 10.2139/ssrn.6383378

Co-Boost: Boosting and guiding neuroplasticity by combining ketamine with neurofeedback-assisted learning – towards an individualised and integrated pharmaco-psychotherapy for cocaine addiction: study protocol for a randomised, placebo-controlled, double-blind, parallel-group, single-centre trial

Anna Stefania Trippel, Ladina Philomena Gubser, Etna Jennifer Elektra Engeli et al.

A randomized, placebo-controlled, double-blind trial will test a single ketamine infusion, three sessions of reward-imagery real-time fMRI neurofeedback training, and their combination in 120 people with cocaine use disorder. The study expects both interventions to reduce the proportion of cocaine use days, with ketamine increasing glutamate in the reward system and lowering craving, and neurofeedback re-sensitizing participants to natural rewards. This neurobiologically informed approach aims to open new treatment avenues through individualized pharmaco-psychotherapy.

DOI: 10.21203/rs.3.rs-5677691/v1

Qualitative analysis of a patient’s experience of ketamine-assisted psychotherapy for substance use disorder: Empirical synergies with twelve-step programs.

Dan Petrovitch, Jacob Spinks, Hannah B Yoo et al. preprint

A 28-year-old woman with alcohol and prescription opioid misuse underwent a collaborative treatment plan that combined ketamine-assisted psychotherapy with existing psychosocial and 12-step-based treatments. The patient attributed psychological and spiritual changes to her ketamine treatments, and her ketamine-induced experiences overlapped with the 12 steps. The report details clinical practices for managing the unique risks of ketamine interventions as substance use disorder treatments.

DOI: 10.31234/osf.io/f53wp_v1

Improvement in Depressive Symptoms in a Patient with Severe and Enduring Anorexia Nervosa and Comorbid Major Depressive Disorder Using Psychotherapy-Assisted IV Ketamine : A Case Report

Amanda Timek, Catherine Daniels-Brady, Stephen Ferrando

A 33-year-old woman with severe and enduring anorexia nervosa and major depressive disorder, who had not improved with numerous prior treatments including antidepressants, mood stabilizers, antipsychotics, electroconvulsive therapy, and various therapies, received seven sessions of intravenous ketamine combined with acceptance and commitment therapy in a hospital setting. She showed increased cognitive flexibility, disappearance of suicidal ideation, and reduction in Beck Depression Inventory scores. Her body mass index was profoundly low at 13, whereas the lowest previously documented in the literature was 16.9. Ketamine-assisted psychotherapy may be a promising treatment for patients with anorexia nervosa and comorbid depression who have failed other interventions.

DOI: 10.21203/rs.3.rs-3976846/v1

Suggestions effects in psychedelics: Confounds and opportunities

Madeline Victore Stein, Devin B. Terhune 1 citation preprint

Growing excitement about psychedelics in media and science often overlooks the influence of suggestion—where expectations and beliefs shape outcomes. Suggestion can distort experimental research on psychedelics' neurocognitive effects, yet it may also enhance therapeutic results when used deliberately. The authors call for greater attention to suggestion as both a source of bias and a potential tool to maximize benefits in psychedelic-assisted therapy.

DOI: 10.31234/osf.io/5krs4

Clinical trials

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