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Scott Shannon

Wholeness Center, Fort Collins, CO, USA.

4 papers in the library · 1,062 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 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.

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.