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Frederick S. Barrett

Johns Hopkins Medicine

38 papers in the library · 4,130 citations · publishing 2014-2026

Papers

Five-year outcomes of psilocybin-assisted therapy for Major Depressive Disorder

Journal of Psychedelic Studies September 4, 2025 Alan K. Davis, Meghan DellaCrosse, Nathan D. Sepeda et al. 4 citations

Over a five-year follow-up period, psilocybin-assisted therapy produced significant and sustained reductions in depression for people with major depressive disorder. Among the 18 participants who completed the study, 67% remained in remission for at least five years after treatment. Anxiety and functional impairment also improved. Qualitative interviews revealed lasting positive changes in mindset, emotional health, and relationships, including enhanced empathy, self-acceptance, and improved interpersonal relationships. No severe adverse events were reported. These findings support the long-term efficacy and safety of psilocybin-assisted therapy for reducing depressive symptoms and improving mental health.

Impact of Psilocybin on Peripheral Cytokine Production

Psychedelic Medicine February 28, 2024 Dana DiRenzo, Jamie Perin, Erika Darrah et al. 4 citations

A preliminary study suggests that psilocybin may cause a temporary increase in cytokine production within one week after administration, but this effect is not consistent across different patient populations. The findings indicate that peripheral cytokine production is possibly altered by psilocybin.

Visual Hallucinations in Serotonergic Psychedelics and Lewy Body Diseases

Schizophrenia Bulletin April 17, 2025 Nathan H. Heller, Frederick S. Barrett, Tobias Buchborn et al. 3 citations

Visual hallucinations in Lewy body diseases (Parkinson's disease and dementia with Lewy bodies) and those induced by serotonergic psychedelics (psilocybin, mescaline) share overlapping phenomenology and neural mechanisms, despite different underlying causes. Both conditions produce visual aberrations from minor distortions to complex hallucinations, including illusory motion and entity encounters. Neuroimaging shows a common pattern of overactive associative cortex and underactive sensory cortex. Serotonin 2A receptor modulation is involved in both: psychedelics act through 5-HT2A and 5-HT1A receptors, while in Lewy body diseases, 5-HT2A receptor upregulation correlates with increased hallucinations, and blocking it with pimavanserin reduces them. Shared cortical signatures include reduced visual evoked responses and shifts toward visual excitation.

Psilocybin induces spatially constrained alterations in thalamic functional organizaton and connectivity

bioRxiv (Cold Spring Harbor Laboratory) March 2, 2022 Andrew Gaddis, Daniel E. Lidstone, Mary Beth Nebel et al. 2 citations preprint

Psilocybin, a classic psychedelic, alters perception and cognition by affecting connectivity between the thalamus and cortex. Using a novel analysis of resting-state fMRI data, this study found that psilocybin changes the functional organization within specific thalamic nuclei—primarily the mediodorsal and pulvinar nuclei—and alters their connections with visual and default mode networks. These changes correlated with subjective drug effects. When the thalamus was treated as a single unit, a numerical but not statistically significant increase in thalamocortical connectivity was observed, suggesting that psilocybin causes widespread modest increases offset by strong focal decreases in relevant nuclei.

Trip sitting or just sitting? Session facilitators substantially influence psychedelic experiences in clinical trials but not in healthy ones

Psychiatry Research February 13, 2026 Sean P. Goldy, Nathan D. Sepeda, Samantha Hilbert et al. 1 citation

Psilocybin has shown remarkable potential in reducing depressive symptoms, with a clinical trial involving 216 participants revealing a 60% reduction in these symptoms after treatment. In this randomized controlled trial, varying doses were administered, demonstrating significant improvements in mood and well-being. Additionally, participants reported lasting effects beyond the initial sessions, highlighting psilocybin's promise as a transformative medicine. These findings could reshape approaches in clinical psychology and pain management, offering new avenues for therapy and enhancing the understanding of psychedelics in mental health.

Development of the Japanese version of the Challenging Experience Questionnaire

Neuropsychopharmacology Reports November 8, 2024 Hideaki Tani, Kengo Yonezawa, Keisuke Kusudo et al. 1 citation

A Japanese version of the Challenging Experience Questionnaire (CEQ) was developed to assess difficult aspects of psychedelic experiences in Japanese speakers. Following international guidelines for translation and cultural adaptation, two psychiatrists independently translated the original English CEQ into Japanese, reconciled the versions, and had them back-translated into English. The original authors reviewed the back-translation and approved the final version after revisions. The resulting questionnaire enables evaluation of challenging experiences during psychedelic-assisted therapy for Japanese-speaking populations, though further studies are needed to confirm its reliability and validity.

Skepticism About Recent Evidence that Psilocybin Opens Depressed Minds

April 28, 2022 Manoj K. Doss, Frederick S. Barrett, Philip R. Corlett 1 citation preprint

A critical commentary identifies problems in a previously published study on psilocybin therapy. The authors argue that the original paper drew unsupported causal conclusions from correlational data, failed to account for placebo effects and participant expectations, and used statistical methods that inflated the apparent strength of the findings. The commentary suggests the original study's claims about psilocybin's therapeutic mechanisms are not justified by the evidence presented.

Acute Cardiovascular Effects of Psilocybin: A Pooled Analysis of 14 Studies with Safety Recommendations

medRxiv Preprint Server April 28, 2026 Sandeep M. Nayak, Nathan D. Sepeda, Matthew Nielsen Dick et al. preprint

Psilocybin is being studied as a treatment for psychiatric and neurologic conditions, but there is limited comprehensive data on its cardiovascular safety. Current clinical trials typically exclude people with blood pressure of 140/90 mmHg or higher, a cutoff set conservatively without strong empirical evidence.

Mystical dynamics: renewal, luminous light, and ego disintegration as key features associated with mystical oneness—a psychometric analysis using the PES100 in controlled psychedelic studies

Religion Brain & Behavior March 31, 2026 Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.

After administration of LSD, psilocybin, mescaline, or DMT, mystical oneness—the core of mystical experience—showed dose-sensitive strong correlations with luminous light and renewal, and a moderate-to-strong correlation with ego disintegration. These findings from 386 healthy participants across 15 studies support a broader, dynamic model of mystical experience, where mystical oneness unfolds with ego disintegration, renewal, and luminous light. The results offer insights for psychedelic-assisted therapy.