ACS Pharmacol Transl Sci
December 10, 2020
David B. Yaden, Roland R. Griffiths
534 citations
Classic psychedelics induce altered states of consciousness that people often find meaningful. In human studies, when the overall intensity of drug effects is statistically controlled, specific subjective experiences—not just neurobiological changes—predict therapeutic and other positive outcomes. The authors argue that these subjective effects are necessary for lasting benefits and account for most of the improvement, while underlying brain mechanisms are likely necessary but insufficient on their own.
JAMA Psychiatry
October 1, 2022
David B. Yaden, James B. Potash, Roland R. Griffiths
153 citations
Public perception of psychedelics has swung from extreme stigma to uncritical enthusiasm, creating obstacles for clinical application. This viewpoint argues that both poles are problematic and advocates for continued scientific study while encouraging critical examination of claims not supported by evidence. The authors call for a balanced approach that neither dismisses therapeutic potential nor overpromises benefits, emphasizing the need for rigorous research to guide responsible clinical integration.
JAMA Psychiatry
September 4, 2024
Marianna Graziosi, Jared T. Hinkle, Sandeep M. Nayak et al.
126 citations
Classic psychedelics such as LSD and psilocybin are generally well tolerated in clinical or research settings, though serious adverse events do occur. In a systematic review and meta-analysis of 214 studies, serious adverse events were reported for no healthy participants and for about 4% of participants with preexisting neuropsychiatric disorders, including worsening depression, suicidal behavior, psychosis, and convulsive episodes. Nonserious adverse events requiring medical intervention, such as paranoia and headache, were rare. In contemporary research, no deaths by suicide, persistent psychotic disorders, or hallucinogen persisting perception disorders were reported after high-dose psychedelic administration. However, the quality of adverse event monitoring and reporting varied significantly across studies.
Journal of Humanistic Psychology
October 24, 2016
David B. Yaden, Khoa D. Le Nguyen, Margaret L. Kern et al.
125 citations
Religious, spiritual, or mystical experiences triggered by psychedelic substances are rated as more intensely mystical and produce a reduced fear of death, a greater sense of purpose, and increased spirituality compared to similar experiences arising through other means. These findings held even after controlling for gender, education, socioeconomic status, and religious affiliation. The results support the view that psychedelic-induced experiences are genuinely mystical and generally positive in outcome.
Frontiers in Psychology
May 23, 2022
David B. Yaden, Dylan Earp, Marianna Graziosi et al.
106 citations
The acute effects of psychedelics depend on users' expectations and surroundings (set and setting). Current clinical psychedelic administration draws on indigenous practices, 1960s new age spirituality, psychodynamic approaches, and cognitive-behavioral therapies. Cognitive-behavioral therapies, including acceptance and commitment therapy (ACT), have the strongest rationale for psychedelic-assisted psychotherapy because they avoid cultural insensitivity, make minimal speculative assumptions about the mind and reality, and have the largest empirical support for safety and effectiveness outside psychedelic therapy. Concepts from CBT, DBT, and ACT can usefully inform preparation, session, and integration phases. Evidence-based psychotherapeutic paradigms provide the best starting point for safety and efficacy.
JAMA Psychiatry
May 1, 2021
David B. Yaden, Mary E. Yaden, Roland R. Griffiths
102 citations
No Summary
August 18, 2022
David B. Yaden, Andrew B. Newberg
80 citations
Spiritual experiences have been reported worldwide throughout history, including the present day. Founders of major religions, philosophers since ancient Greeks, and about 30% of people in the United States and United Kingdom report them. William James analyzed these experiences a century ago, raising questions about triggers, brain and body effects, and lasting impacts. This book explores modern scientific breakthroughs from psychology and neuroscience, inviting readers into laboratories to learn research methods. It includes survey questions for classifying experiences and diverse personal accounts. Building on James's foundation, it provides a scientifically informed contemporary understanding of these profound, often life-meaningful events.
Psychology of Religion and Spirituality
July 27, 2015
David B. Yaden, Johannes C. Eichstaedt, H. Andrew Schwartz et al.
68 citations
People who report having had mystical experiences use language that is more socially and spatially inclusive—words like 'close,' 'we,' and 'with'—and fewer overtly religious terms such as 'prayed,' 'Christ,' or 'church' compared to those who have not had such experiences. This pattern emerged from quantitative linguistic analysis of 777 participants' written accounts of their most significant spiritual or religious experience. The findings suggest that mystical experiences, though often described as ineffable, can be meaningfully communicated, and that language analysis offers a way to study them.
Journal of Psychopharmacology
June 8, 2023
Natalie Gukasyan, Roland R. Griffiths, David B. Yaden et al.
60 citations
Psilocybin-containing mushrooms produce weaker drug effects in people taking SSRI or SNRI antidepressants, with a 47% probability of weaker-than-expected effects for SSRIs and 55% for SNRIs, compared to 29% for bupropion, a non-serotonergic antidepressant. This dampening effect persists for up to three months after discontinuing the antidepressant, based on retrospective survey data from over 2,000 reports. Removing responses involving fluoxetine, which has a long half-life, did not change the result. The findings suggest that serotonergic antidepressants may reduce psilocybin's effects both during use and for a period after stopping.
Nature Reviews Psychology
September 3, 2024
David B. Yaden, Sean P. Goldy, Brandon Weiss et al.
57 citations
No Summary
The International Journal of Neuropsychopharmacology
May 10, 2021
Natalie Gukasyan, David B. Yaden, Matthew W. Johnson et al.
56 citations
Psychedelic substances produce unusual changes in conscious experience, leading some to propose they offer unique insights into consciousness. However, psychedelics are unlikely to provide information relevant to the "hard problem of consciousness," which involves explaining how first-person experience emerges. Instead, they bear on multiple "easy problems of consciousness," involving relations between subjectivity, brain function, and behavior. This review discusses common meanings of "consciousness" regarding psychedelics and considers models of their effects on the brain linked to explanatory claims about consciousness. It calls for epistemic humility about psychedelic research's potential to explain the hard problem while noting ways psychedelics may advance study of specific aspects of consciousness.
Psychoactives
April 16, 2024
Daniel Meling, Rebecca Ehrenkranz, Sandeep M. Nayak et al.
26 citations
Psychedelic research has returned after a period of suppression, but media coverage now often overstates benefits as much as it once overstated risks. The actual evidence is more mixed than commonly portrayed, so conclusions about effectiveness remain preliminary. Poor communication may mislead patients and misinform policy. This article reviews studies on psychedelics for depression, noting that effect sizes for other depression treatments—cognitive behavioral therapy, mindfulness, SSRIs, and ketamine—have decreased over time as trials improved. The authors suggest the same may happen for psychedelics: larger, better-controlled trials will likely show smaller, more realistic benefits. Clear communication is essential to set public expectations and guide policy.
Frontiers in Psychology
May 23, 2022
Tomas Frymann, Sophie Whitney, David B. Yaden et al.
26 citations
Two new psychometric scales, the Integration Engagement Scale (IES) and the Experienced Integration Scale (EIS), were developed to measure different aspects of psychedelic integration—the period after acute drug effects. The IES captures positive behavioral engagement with integration, while the EIS captures internal feelings of being integrated. Scale items were refined with input from experts and clinicians using the Iterative Process Model. Content validity, internal structure, and reliability were assessed through expert surveys, cognitive interviewing, convergent validity analysis, exploratory and confirmatory factor analysis. The data indicate the scales are valid and reliable measures of behavioral and experiential forms of psychedelic integration.
Religion Brain & Behavior
March 22, 2017
Andrew B. Newberg, Nancy Wintering, David B. Yaden et al.
19 citations
A seven-day spiritual retreat involving meditation and prayer led to measurable changes in brain chemistry. After the retreat, dopamine transporter binding decreased in the basal ganglia and serotonin transporter binding decreased in the midbrain, suggesting altered neurotransmitter activity. Participants also reported changes in psychological and spiritual measures. This preliminary study of 14 individuals provides the first neurophysiological data on such retreats, though the authors note methodological challenges for future research.
Psychiatr Res Clin Pract
February 11, 2025
Jules Evans, Marc Aixalà, Brian T. Anderson et al.
18 citations
Thirty psychedelic researchers identified critical gaps in knowledge about harms from psychedelic use, including how to define those harms, predict them, and treat them effectively. They recommend better online information, peer support groups, affordable therapy, and psychiatric consultation for people experiencing post-psychedelic difficulties. The researchers also call for improved funding for a psychedelic safety net, suggesting that psychedelic philanthropists, investors, and companies commit 1% of their investment to support safety measures such as research and support services. The article outlines practical steps to make the field of psychedelic medicine safer.
Psychedelic Medicine
October 28, 2022
Bruna Giribaldi, Sandeep M. Nayak, Bilal A. Bari et al.
15 citations
A Bayesian reanalysis of a trial comparing psilocybin (25 mg) to escitalopram (20 mg) over 6 weeks in 59 patients with major depressive disorder found that psilocybin outperformed escitalopram on three of four depression scales, though evidence was not uniformly clinically meaningful. Using skeptical priors that bias results toward zero, the analysis showed strong to extremely strong evidence favoring psilocybin on the BDI-1A, MADRS, and HAMD-17, while evidence on the primary outcome (QIDS SR-16) was indeterminate. For clinically meaningful superiority, evidence was moderate against it for the QIDS SR-16 but moderate to strong for the MADRS and HAMD-17. Psilocybin showed extremely strong evidence of noninferiority to escitalopram across all scales. The findings support further research on psilocybin's relative efficacy.
Psychology of Consciousness Theory Research and Practice
June 12, 2025
Etzel Cardeña, Aviva Berkovich‐ohana, Katja Valli et al.
11 citations
A multidisciplinary, international group used taxonomic principles and a modified Delphi method to create a taxonomy of altered states of consciousness based on central phenomenological features. They identified eight distinct states, some with subcategories: proto and transitional, delirium, minimal to no awareness, experiential detachment, enhanced physicality, altered identity, imaginary/fantasy/visionary, and unity/mystical. The authors hope this taxonomy will foster conceptual clarity and stimulate research across specializations, helping reveal what is common and different across triggers and antecedents of altered states, and encouraging phenomenological, psychological, cultural, and neuroscientific understanding.
International Review of Psychiatry
June 5, 2024
Katherine Cheung, Caleigh Propes, Edward Jacobs et al.
11 citations
Psychedelic integration groups, offered in person or online, may attract individuals who feel disconnected or lonely after a psychedelic experience. These groups can provide community and shared coping strategies, but also carry risks. This essay explores both benefits and risks, offering preliminary guidelines for physicians, researchers, and individuals to assess and evaluate such groups.
Journal of Psychoactive Drugs
September 7, 2023
Marianna Graziosi, Manvir Singh, Sandeep M. Nayak et al.
10 citations
Reports of psychedelic experiences show both similarities and differences across cultural contexts, yet most current characterizations come from Western medical and naturalistic settings. This article reviews the history of diverse psychedelic use in non-Western settings and compares accounts of acute subjective effects within and beyond Western, educated, industrialized, rich, and democratic (WEIRD) contexts. It contrasts themes from direct testimony and psychometric measures including the mystical experiences questionnaire, five-dimensional altered states of consciousness scale, Survey of God Encounters, Survey of Entity Encounters, Challenging Experiences Questionnaire, and Inventory of Nonordinary Experiences. Recommendations are offered for future empirical research to quantify cross-cultural similarities and differences.
Psychedelic Medicine
January 20, 2025
Marianna Graziosi, Gabrielle Agin-Liebes, Mary P Cosimano et al.
9 citations
Psilocybin and other serotonergic psychedelics are used in research settings with safety measures including controlled environments, staff presence, screening, and psychoeducation. An analysis of study materials from psilocybin trials over the past two decades found that psychoeducation documents varied but commonly emphasized biological and physical safety, psychological safety and well-being, aspects of setting, and the potential for expectancies. The materials prioritized biological and psychological safety across all sites. The authors also identified elements unrelated to safety that may contribute to participant expectancies and suggest these extrapharmacological factors be studied systematically to maximize safety while minimizing extraneous expectancies.
Psychedelic Medicine
June 1, 2023
Praachi Tiwari, Andrea Berghella, Ceyda Sayalı et al.
9 citations
Classic psychedelics may treat mood and substance use disorders by reversing learned helplessness, a well-studied phenomenon across mammals. The neural circuits underlying resilience to learned helplessness, including the dorsal raphe nucleus, overlap with those activated by psychedelics. Preclinical data show psychedelics improve performance in rodent behavioral despair tasks, supporting this hypothesis. The learned helplessness paradigm offers a robust model for investigating psychedelic mechanisms across behavioral, neurobiological, and clinical levels, potentially explaining transdiagnostic therapeutic effects.
The Lancet Child & Adolescent Health
September 2, 2025
Khaleel Rajwani, Edward Jacobs, Lori Bruce et al.
6 citations
A scoping review of medical literature from 2000 to 2025 found no completed or published clinical trials testing psychedelic-assisted therapy in adolescents under 18, despite three trial registrations and one trial plan. The proposed studies would have investigated MDMA-assisted or psilocybin-assisted psychotherapy for adolescents with post-traumatic stress disorder, autism with social anxiety, or self-harm. Ethical approval and recruitment details were inconsistently reported. This absence of data represents a major evidence gap that could hinder informed care. The authors argue for cautious, ethically grounded research starting with older adolescents who have the highest foreseeable benefit-risk ratio due to special circumstances.
Frontiers in Psychology
January 1, 2023
Katherine Cheung, David B. Yaden
6 citations
A general commentary on a previously published article, offering critical perspective or additional context on the topic of consciousness research. The commentary engages with the original work's arguments, highlighting areas of agreement or disagreement and suggesting refinements or future directions for the field.
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.
International Review of Psychiatry
May 23, 2024
Rebecca Ehrenkranz, Manish Agrawal, J. Kim Penberthy et al.
5 citations
Prolonged Grief Disorder (PGD) affects up to 10% of bereaved people, causing functional impairment and intense yearning for at least a year after loss. Current treatments are mainly psychological, and more options are needed. Psychedelics like psilocybin and MDMA may help because they reduce depression and PTSD symptoms in clinical trials and produce subjective effects relevant to existential distress in PGD. No randomized clinical trials have yet tested psychedelics for PGD, but initial survey and open-label studies suggest a consistent trend toward grief reduction. A randomized clinical trial is the appropriate next step to explore this potential.