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Scott Shannon

10 papers in the library · 1,470 citations · publishing 2021-2026

Papers

MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study.

Nature medicine June 1, 2021 Jennifer M Mitchell, Michael Bogenschutz, Alia Lilienstein et al. 965 citations

A phase 3 clinical trial tested MDMA-assisted therapy against placebo for severe PTSD. Participants received manualized therapy with either MDMA or placebo alongside preparatory and integrative sessions. At two months after the last session, the MDMA group showed a significantly greater reduction in PTSD symptoms (average 24.4-point drop on the CAPS-5 scale) compared to the placebo group (13.9-point drop), with a large effect size. Functional impairment also improved more with MDMA. No serious safety issues such as abuse potential, suicidality, or heart rhythm problems were observed. The findings suggest MDMA-assisted therapy is highly effective and safe for severe PTSD, including in people with common co-occurring conditions.

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

Nature medicine October 1, 2023 Jennifer M. Mitchell, Marcela Ot’alora G., Bessel Van der Kolk et al. 400 citations

In a phase 3 trial, MDMA-assisted therapy reduced PTSD symptoms and functional impairment more than placebo with therapy in 104 participants with moderate to severe PTSD. The average decrease in PTSD symptom severity was 23.7 points with MDMA-assisted therapy versus 14.8 points with placebo, and functional disability improved by 3.3 versus 2.1 points. Participants were ethnoracially diverse, with 27% identifying as Hispanic/Latino and 34% as other than White. Severe side effects occurred in 9.4% of the MDMA group and 3.9% of the placebo group; no deaths or serious adverse events were reported. The treatment was generally well tolerated.

MDMA-Assisted Therapy for Severe PTSD: A Randomized, Double-Blind, Placebo-Controlled Phase 3 Study.

Focus (American Psychiatric Publishing) July 1, 2023 Jennifer M Mitchell, Michael Bogenschutz, Alia Lilienstein et al. 97 citations

A phase 3 clinical trial tested MDMA-assisted therapy for severe PTSD. In 90 participants randomized to receive either MDMA or placebo alongside therapy, those receiving MDMA showed a significantly larger reduction in PTSD symptoms, with an average decrease of 24.4 points on the CAPS-5 scale compared to 13.9 points in the placebo group. Functional impairment also improved more with MDMA. No serious safety issues like abuse potential or suicidality were observed. The treatment was effective even for patients with common co-occurring conditions such as depression or substance use history. The authors conclude MDMA-assisted therapy is a safe and highly effective treatment for severe PTSD.

MDMA for PTSD and beyond: a new paradigm brings hope.

Front Hum Neurosci December 11, 2024 Scott Shannon, Jamarie Geller 3 citations

Post-traumatic stress disorder (PTSD) affects over 13 million people in the US annually, with women experiencing it at two to three times the rate of men and higher rates among African Americans, Latinos, Native Americans, and the homeless. Current treatments are inadequate: only about 50% of patients complete trauma-focused psychological therapy, and response rates among those who do are roughly 50%; approved medications like sertraline and paroxetine have small effect sizes (0.28 and 0.23). MDMA-assisted psychotherapy (MDMA-AP) represents a paradigm shift, combining a psychotherapeutic container, the MDMA catalyst, and a carrier of music and eyeshades. Phase III studies show a large effect size of 0.91 with no serious adverse effects, offering durable improvement and potential transdiagnostic utility for trauma-related conditions.

Ketamine-Assisted Group Therapy for Work-Related Stress in First Responders and Frontline Health Care Workers

Psychedelic Medicine April 21, 2025 Luke Flynn, Mary Rondeau, Martin Krsak et al. 1 citation

A 6-week community-based group ketamine-assisted psychotherapy (KAP) program reduced symptoms of trauma, anxiety, and depression in a sample of 16 first responders and frontline health care workers experiencing work-related stress. Participants completed the program in small groups of three to six. Pre- and post-treatment comparisons using standardized measures showed significant reductions in trauma, anxiety, and depression scores. The findings suggest that group KAP may be a useful treatment for work-related stress, though further formal evaluation is needed.

Systems-based psychiatry: insights from psychedelic research on mechanisms of healing

Frontiers in Psychiatry July 13, 2026 Scott Shannon, Andrew Weil

Psychiatric models that focus on isolated biological dysfunction fail to capture the complexity and context dependence of mental disorders. Drawing on neuroscience, complexity science, and psychedelic research, this paper proposes a systems-based framework where therapeutic change involves a phased process of perturbation, reorganization, and consolidation. Interventions modulate system stability and plasticity, with outcomes shaped by biological, psychological, relational, and environmental factors. Psychedelic-assisted therapies exemplify this by transiently destabilizing entrenched patterns, increasing flexibility, and enabling reorganization under supportive conditions. Recovery is reframed as increased coherence, flexibility, and adaptive capacity rather than mere symptom reduction. This perspective calls for longitudinal, context-sensitive outcome measures and hybrid methodologies.

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

Psychotherapy and psychosomatics June 19, 2026 Judith Rohde, Tyler M Moore, Kathryn Walker et al.

A systematic review and individual participant data meta-analysis of 12 studies (533 participants) found that higher baseline PTSD severity was the most robust predictor of symptom reduction after combined ketamine and psychotherapy. More psychotherapy sessions, more ketamine sessions, and shorter treatment duration were also associated with greater improvement, but these findings are tentative because most studies were of poor quality. The analysis showed that for each additional psychotherapy session, PTSD symptoms improved by an average of 1.03 points on the PCL-5, and for each additional ketamine session, improvement was 1.15 points. The results require confirmation in well-designed prospective trials.

Treating job-related stress with psychedelic group therapy: a case series on group ketamine-assisted psychotherapy for healthcare workers and first responders

Therapeutic Advances in Psychopharmacology October 1, 2025 Luke Flynn, Martin Krsak, Mary Rondeau et al.

A group ketamine-assisted psychotherapy program for frontline healthcare workers and first responders reduced symptoms of anxiety, depression, trauma, and burnout. Median scores on the GAD-7 (anxiety) dropped from 9.5 to 6, PHQ-9 (depression) from 12 to 5, and PCL-5 (trauma) from 27 to 10, all with statistically significant improvements. The Maslach Burnout Inventory also improved across all subcomponents. The seven-week program included three ketamine sessions and four group psychotherapy sessions. Adverse events were rare, suggesting this model may be a viable intervention for job-related stress, though larger controlled studies are needed.

Ketamine-Assisted Group Psychotherapy for Frontline Healthcare Workers with COVID-19-Related Burnout and PTSD: A Case Series of Effectiveness/Safety for 10 Participants.

Journal of psychoactive drugs January 1, 2024 Reid Robison, Madeline Brendle, Claire Moore et al.

Ten frontline healthcare workers with burnout and PTSD symptoms were treated with group ketamine-assisted psychotherapy (KAP) in a private clinic. They attended six weekly sessions: one preparation, three ketamine sessions (two sublingual, one intramuscular), and two integration sessions. PTSD, depression, and anxiety scores improved from pre- to post-treatment, with a 59% reduction in PTSD scores, 58% reduction in depression scores, and 36% reduction in anxiety scores. After treatment, all participants screened negative for PTSD, 90% had minimal or mild depression, and 60% had minimal or mild anxiety. Ketamine was well tolerated with no significant adverse events. Participant feedback supported the improvements.