EClinicalMedicine
September 24, 2025
Megan Hosein, Matthew J Reid, Sarah A. Walser et al.
5 citations
Psilocybin and other psychedelics show promise as a new class of psychiatric treatments, but their rapid development risks outpacing the guidelines and infrastructure needed for safe clinical integration. A consensus statement from the US National Network of Depression Centers (NNDC) Task Group on Psychedelics and Related Compounds, comprising psychiatrists, psychologists, neuroscientists, psychedelic researchers, and healthcare consultants, recognizes psilocybin's therapeutic potential while emphasizing the need for further research. Key gaps include understanding therapeutic dosage, efficacy across diverse populations, and long-term safety. The authors call for diversified funding, collaborative research, standardized provider training, and careful ethical consideration. They advocate for a balanced approach prioritizing rigorous science and equitable access, noting the single-country focus limits international generalizability.
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.
Neuropsychopharmacology
August 6, 2024
Nathan H. Heller, Frederick S. Barrett
4 citations
No Summary
Psychedelic Medicine
February 28, 2024
Dana D. 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.
Drug and Alcohol Dependence
December 16, 2014
Frederick S. Barrett, Matthew P. Bradstreet, Jeannie‐marie Leoutsakos et al.
4 citations
No Summary
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.
Drug and Alcohol Dependence
December 16, 2014
Theresa M. Carbonaro, Frederick S. Barrett, Matthew P. Bradstreet et al.
3 citations
No Summary
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.
Psychiatry Research
February 13, 2026
Sean P. Goldy, Nathan D. Sepeda, Samantha Hilbert et al.
1 citation
The acute subjective effects of psychedelics are known to predict therapeutic benefits like reduced depression and anxiety. Session facilitators—who support participants before, during, and after dosing—are a key part of the setting, but their influence on subjective effects was unclear. Analyzing data from 9 psilocybin studies with 298 participants, 670 sessions, and 60 facilitators, multilevel models showed facilitators accounted for negligible variance (0.8%) in healthy volunteers but greater variance in clinical samples (13.6%), after controlling for study and participant differences. This suggests facilitators may play a clinically meaningful role in shaping outcomes for patient populations, comparable to or exceeding therapist effects in traditional psychotherapy (~8%).
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.
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.
International Journal of Methods in Psychiatric Research
June 1, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
The eight-factor structure of the Psychedelic Experience Scale (PES48), which includes the Mystical Experience Questionnaire (MEQ30) and additional factors for paradoxicality, connectedness, visual experience, and distressing experience, is valid for use in English. Analysis of 280 measurements from 145 healthy participants in four placebo-controlled psilocybin studies found that six subscales have high internal consistency, one good, and one acceptable. Both the MEQ30 and MEQ40 models show acceptable to good model fits, with better fits in English than in German. All six MEQ40 scale means were higher in English data, suggesting that the PES48 provides a broader conceptualization of mystical and non-mystical psychedelic experiences, and that setting may influence mystical experience.
Psychopharmacology
May 28, 2026
Mazen A Atiq, Eli Weisman, Rodrigo B Guerra et al.
A healthy 35-year-old man experienced a rare hypotensive adverse event—neurocardiogenic syncope (fainting)—about 60 minutes after taking 25 mg of oral psilocybin in a clinical trial. His blood pressure dropped to 93/51 mmHg, with rapid heart rate and sweating, but he stabilized quickly with leg elevation and oral hydration. The episode may have been triggered by upright seated posture, restrictive EEG equipment, and anxiety about upcoming transcranial magnetic stimulation. Fewer than one-quarter of contemporary psychedelic trials report systematic adverse event assessment, highlighting the need for transparent documentation of both hypertensive and hypotensive events as psilocybin moves toward potential FDA approval.
Repository for Publications and Research Data (ETH Zurich)
April 30, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
The Psychedelic Experience Scale (PES48) has an eight-factor structure that includes the well-validated Mystical Experience Questionnaire (MEQ30) plus four additional factors: paradoxicality, connectedness, visual experience, and distressing experience. This study tested whether the full eight-factor structure is valid in English, using data from 280 PES measurements from 145 healthy participants in four placebo-controlled psilocybin studies. Six of the eight subscales showed high internal consistency, one good, and one acceptable. Confirmatory factor analysis indicated acceptable to good model fits for the MEQ30 and MEQ40, with English data showing better fits than the German validation sample. The findings suggest the PES48 is a valid psychometric tool in English, enabling broader measurement of mystical and non-mystical aspects of psychedelic experience.
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.
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.
Journal of psychopharmacology (Oxford, England)
February 5, 2026
Benjamin R. Lewis, Matthew J Reid, Andrew M Novick et al.
Clinical trials of classical psychedelics like psilocybin for mental health conditions face unique challenges that may persist if these treatments enter clinical practice. Four categories of challenges with trial participants are identified: treatment nonresponse, expectancy effects and functional unblinding, post-session psychological difficulties, and contagion effects. Management strategies for study teams to mitigate these risks are described. The National Network of Depression Centers and similar organizations can guide best practices to responsibly advance this promising field.
Journal of psychopharmacology (Oxford, England)
January 1, 2026
Jack E Henningfield, Frederick S. Barrett, Suzette M Evans et al.
Roland R. Griffiths was a highly influential scientist in behavioral and neuropsychopharmacology, known for his rigorous research on abuse liability of substances including alcohol, benzodiazepines, caffeine, tobacco, and psychedelics. This review, authored by his former mentees and collaborators, describes his methodical approach to research, his inclusive and collegial mentoring style, and his role in advancing scientific methods for abuse liability assessment, policy, and regulation. His work culminated in the establishment of the Johns Hopkins Center for Psychedelic and Consciousness Research, reflecting his curiosity-driven, humanity-serving science that continues to inspire innovation.
Repository for Publications and Research Data (ETH Zurich)
January 1, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
Mystical oneness after psychedelics is linked to ego disintegration, renewal, and luminous light, and these connections intensify with higher doses. Analyzing 816 measurements from 386 healthy participants given LSD, psilocybin, mescaline, or DMT across 15 studies, researchers found dose-sensitive strong correlations between mystical oneness and luminous light and renewal, and a moderate-to-strong correlation with ego disintegration. The results support a dynamic model of mystical experience and suggest relevance for psychedelic-assisted therapy.
Drug and Alcohol Dependence
July 1, 2024
Alan K. Davis, Adam W. Levin, Rafael Lancelotta et al.
No Summary
Neuroimage
May 4, 2023
Andrew Gaddis, Daniel E. Lidstone, Mary Beth Nebel et al.
correction
No Summary
Clinical Chemistry
March 7, 2023
Steven W. Cotten, Frederick G. Strathmann, Frederick S. Barrett et al.
Experts in psychedelic research, drug discovery, and regulation discuss the challenges of clinical adoption of psychedelic compounds and their impact on laboratory medicine. FDA approval of psychedelics like psilocybin, which has Phase III trials for major depressive disorder and treatment-resistant depression, would be a major milestone. Approval would require federal workplace drug testing guidelines to address new prescription drugs, potential false positives, and Medical Review Officer decisions. Laboratories must adapt by evaluating test panels, analytical ranges, and interpretive comments. Media portrayal ranges from dangerous drugs to panaceas, but regulatory decisions should rely on objective scientific data. Patients with mood and substance use disorders stand to benefit most.
Research Square
April 20, 2022
Aviv Aharon-Almagor, Frederick S. Barrett
People who have used hallucinogens show greater openness to new experiences and higher cognitive ability scores compared to non-users, along with denser structural connectivity in white matter tracts linked to cognition, emotion, and creativity. The study compared 53 hallucinogen users with 53 matched non-users from a public database, using diffusion tensor imaging and psychological assessments. Hallucinogen users also reported more lifetime use of other illicit drugs. These findings suggest hallucinogen use may be associated with lasting changes in brain structure and personality, offering clues to possible neural mechanisms behind therapeutic effects.