Journal of Psychopharmacology
May 14, 2019
Albert Garcia-Romeu, Alan K Davis, Fire Erowid et al.
286 citations
In a survey of 343 people who had problematic alcohol use for an average of seven years and then used psychedelics in non-clinical settings, 83% no longer met criteria for alcohol use disorder after the experience. Most respondents were White males in the USA who took moderate or high doses of LSD or psilocybin. They rated the experience as highly meaningful and insightful, and 28% said changes in life priorities or values helped reduce alcohol misuse. Greater dose, insight, mystical-type effects, and personal meaning were linked to larger reductions in drinking. The results suggest naturalistic psychedelic use may reduce problematic alcohol use, supporting further research into psychedelic-assisted treatment.
Exp Clin Psychopharmacol
August 1, 2016
Albert Garcia-Romeu, Brennan Kersgaard, Peter H. Addy
198 citations
Hallucinogens are grouped into classes—psychedelics, entactogens, dissociatives, and others—based on how they work in the brain and their chemical structure. While these classes have different primary mechanisms, they all can temporarily and profoundly change consciousness, affecting body sensations, perception, thinking, and emotions. These effects likely explain their recreational use, but a growing body of evidence suggests therapeutic applications beyond abuse potential. This review covers data on several hallucinogen classes, focusing on psychedelics, entactogens, and dissociatives, where clinical utility is best documented. It traces historical insights, compares classes from molecular to behavioral levels, and presents up-to-date clinical research with implications for therapeutic value.
International Review of Psychiatry
July 4, 2018
Albert Garcia-Romeu, William A. Richards
186 citations
Serotonergic hallucinogens (psychedelics) have been used for millennia, but their integration into Western therapeutic practice is relatively new. Mid-20th-century work developed therapeutic models using both low (psycholytic) and high (psychedelic) doses, often combined with psychoanalytic concepts, and established the importance of set (mindset) and setting (environment) for safe, effective use. Recent clinical and pharmacological research has revisited these substances' therapeutic potential. This article reviews past and present models of psychedelic therapy and discusses key considerations for future research and clinical applications.
Culture, medicine and psychiatry
December 1, 2022
Daniel R George, Ryan Hanson, Darryl Wilkinson et al.
65 citations
An international ban on psychedelics in 1971 restricted clinical use of these ancient substances, but structured psychedelic use—long part of ritual healing—is regaining credibility in Western medicine for treating mental health conditions amid rising 'Deaths of Despair' (excess mortality from suicide, drug overdose, and alcoholism). Using a historical lens, the authors examine psychedelic therapies over time, translate ancient lessons to contemporary practice, and interrogate practical and ethical questions for mainstream medicine. Reflecting on COVID-19's contributions to global mental health burden, they argue that a 'psychedelic renaissance' anchored in antiquity could shift healthcare toward more humane practices attentive to underlying causes of distress and supportive of human flourishing.
Qualitative Research
September 29, 2014
Albert Garcia-Romeu, Samuel P Himelstein, Jacob Kaminker
64 citations
Self-transcendent experiences (STEs) are moments when a person feels connected to something larger than themselves, yet their nature and process are not well understood. Through in-depth interviews with 15 healthy adults, three major themes emerged: the context in which the experience occurs, the phenomenology or what it feels like, and the aftermath or long-term effects. The context includes the setting, the phenomenology involves perceptual changes, and the aftermath includes lasting impacts. These findings help build a preliminary theory of STEs in healthy adults, offering a clearer picture of how these experiences unfold and what they mean for individuals.
EClinicalMedicine
August 1, 2024
Marcus E Hughes, Albert Garcia-Romeu
42 citations
A systematic review of 39 studies published between 1994 and 2024 found that ethnoracial diversity remains low in clinical psychedelic research. Among all included studies (n=1393), 85.0% of participants identified as non-Hispanic White, 2.9% as Black, 5.9% as Latinx/Hispanic, 3.2% as Asian, 1.9% as Indigenous, and 3.7% as mixed race. In studies conducted in the USA (n=1074), 84.5% were White, 3.4% Black, 7.4% Latinx/Hispanic, 4.0% Asian, 1.4% Indigenous, and 3.7% mixed race. The proportion of White to non-White participants decreased in US studies after 2017, indicating some progress, but minoritized groups remain underrepresented.
Journal of psychopharmacology (Oxford, England)
April 1, 2015
Peter H Addy, Albert Garcia-Romeu, Matthew Metzger et al.
38 citations
In a double-blind, randomized, placebo-controlled trial, 30 healthy individuals who inhaled Salvia divinorum reported rapid, intense, and unique experiences. The experience included marked changes in auditory, visual, and internal bodily sensations, loss of normal self and environmental awareness, and various delusional phenomena. Three main themes and 10 subthemes of acute intoxication emerged from qualitative analysis of interviews and follow-ups, supported by quantitative Hallucinogen Rating Scale data. The findings provide an initial framework for understanding the subjective effects of this emerging drug of abuse and also examine its abuse potential post hoc.
Psychopharmacology
April 1, 2023
David S Mathai, Sandeep M Nayak, David B Yaden et al.
36 citations
For esketamine, a form of ketamine used for treatment-resistant depression, there is no clinically meaningful link between how dissociated a person feels during the drug experience and how much their depression improves. Analyzing data from 576 participants across two clinical trials, researchers measured dissociation with the Clinician-Administered Dissociative States Scale (CADSS) and depression with the Montgomery-Åsberg Depression Rating Scale (MADRS). A statistical model found no significant interaction between dissociation and antidepressant effect over four weeks. A separate analysis showed that each additional point on the dissociation scale on day 1 was associated with a very small 0.
The American Journal of Drug and Alcohol Abuse
June 5, 2021
David J. Cox, Albert Garcia-Romeu, Matthew W. Johnson
29 citations
People who quit or reduced using alcohol, cannabis, opioids, or stimulants after a psychedelic experience provided written narratives of that experience. Natural language processing extracted topic models from the narratives, and three machine learning algorithms predicted long-term drug reduction outcomes with about 65% accuracy. The quantitative descriptions of the experiences differed depending on which drug class was quit and whether the reduction was sustained. The findings suggest that analyzing written reports of psychedelic experiences with machine learning could help predict who will benefit from psychedelic therapy for substance use.
Psychedelic medicine (New Rochelle, N.Y.)
March 1, 2024
Justin C Strickland, Albert Garcia-Romeu, Matthew W Johnson
20 citations
Brief four- and seven-item versions of the Mystical Experience Questionnaire (MEQ-4) and Challenging Effects Questionnaire (CEQ-7) show strong correspondence with the full 30- and 26-item scales. In a sample of 1,160 individuals who used psychedelics therapeutically outside research settings, total scores for the brief versus full versions correlated at r = 0.89 for the MEQ and r = 0.90 for the CEQ. Classic psychedelics like LSD and psilocybin produced higher scores on both brief and full versions than MDMA. Higher mystical experience scores on both versions were linked to greater reductions in depression and anxiety, while challenging experiences showed limited association with mental health changes. The brief scales substantially reduce participant burden while maintaining validity.
Scientific reports
November 14, 2024
Erin Wang, David S Mathai, Natalie Gukasyan et al.
18 citations
Among 879 U.S. healthcare professionals surveyed online, most endorsed strong belief in the therapeutic promise of psychedelic-assisted therapy with psilocybin and MDMA, and showed moderate openness to clinical use and support for legal access, with higher ratings for psilocybin than MDMA. However, objective knowledge of therapeutic uses, risks, and pharmacology was low. Primary concerns included lack of trained providers, financial cost, and potential contraindications. Prior psychedelic use, self-rated knowledge, younger age, and professional role predicted greater openness, while physicians reported lower openness. Results indicate a pressing need for formal training to provide balanced, evidence-based information.
Journal of Psychoactive Drugs
May 7, 2024
Sandeep M Nayak, Sydney H White, Samantha N Hilbert et al.
18 citations
A prospective longitudinal study of 657 people planning a psilocybin experience outside a laboratory found that after the experience, participants reported increased perception of minds in various living and non-living entities such as plants and rocks, replicating earlier findings. However, the study found little to no change in participants' metaphysical beliefs, such as dualism, or in their self-reported Atheist-Believer status. These results contrast with cross-sectional studies suggesting psilocybin experiences alter Atheist-Believer status and non-naturalistic beliefs, but they support the relevance of mind perception and mentalization processes.
Journal of affective disorders
September 1, 2022
David S Mathai, Scott M Lee, Victoria Mora et al.
16 citations
Informed consent documents from 23 American ketamine clinics for psychiatric treatment cover most required elements but vary greatly in detail. Key gaps include poor communication about long-term side effects, alternative treatments, pre-treatment evaluations, support during treatment, psychological interventions, and dissociative effects. All forms are written at a readability level too high for many patients. The findings suggest that both patients and providers would benefit from more deliberate, evidence-informed consent processes to support shared decision-making as off-label ketamine use expands.
Journal of affective disorders
February 1, 2025
Grant Jones, Matthew X Lowe, Sandeep Nayak et al.
12 citations
Psilocybin, the psychoactive compound in magic mushrooms, is linked to improved mental wellbeing on average, but few studies examine how effects differ by race. In a large online longitudinal study of 2,833 people planning naturalistic psilocybin use, race/ethnicity moderated changes in spiritual wellbeing, cognitive flexibility, and emotion regulation (expressive suppression) at 2–3 months post-experience, but not at 2–4 weeks. Participants of Color reported minor differences in context and subjective effects, such as being more likely to set an intention before use. Both groups showed comparable reductions in anxiety and depression, with no significant moderation by race.
Pharmacological research
January 1, 2024
David B Yaden, Andrea P Berghella, Peter S Hendricks et al.
12 citations
Classic psychedelic-assisted therapies show initial promise for treating substance use disorders (SUDs) and may become legally available options. This article describes how these therapies could fit within current evidence-based SUD treatments, suggesting broad compatibility with most mainstream clinical approaches.
Therapeutic Advances in Psychopharmacology
January 1, 2024
Baeleigh VanderZwaag, Albert Garcia-Romeu, Mauricio A Garcia-Barrera
9 citations
Psychedelics were the third most used substance in the past year among athletes (35.8%), though regular use was low (7.5%). In a survey of 175 athletes and staff in Canada and the United States, 61.2% of athletes reported likely engaging in psilocybin-assisted therapy (PAT) for concussion recovery, and 71.1% of staff said they would support athletes using PAT. Attitudes toward psilocybin and knowledge of psilocybin predicted willingness to use or support PAT. The sports community may be receptive to PAT for managing persisting concussion symptoms.
JAMA Network Open
March 10, 2026
Mw Johnson, Gideon P. Naudé, Peter S. Hendricks et al.
6 citations
A single high dose of psilocybin combined with cognitive behavioral therapy (CBT) led to significantly higher long-term smoking abstinence rates than nicotine patch treatment plus CBT. At six months, 40.5% of participants who received psilocybin had biochemically verified prolonged abstinence, compared to 10.0% of those using the nicotine patch. No serious adverse events were attributed to either treatment. The pilot trial randomized 82 psychiatrically healthy adult smokers and used an intention-to-treat analysis. The findings suggest psilocybin-assisted therapy may be a promising intervention for tobacco smoking cessation.
Progress in neuro-psychopharmacology & biological psychiatry
April 2, 2025
C J Healy, Aaron Frazier, Stephen Kirsch et al.
6 citations
Adults with histories of childhood maltreatment who used psychedelic drugs with therapeutic intent at ceremonies or raves showed significant improvements in PTSD symptoms, complex PTSD symptoms, trait shame, social connectedness, and general connectedness from before the experience to two months afterward. The size of these improvements was large. Changes in these outcomes were linked to specific aspects of the acute psychedelic experience, such as subjective effects. The findings suggest that the social and psychological context of group psychedelic use may contribute to lasting mental health benefits for this population.
Journal of psychopharmacology (Oxford, England)
February 1, 2025
Sophie-Athéna Chapron, Guilhem Bonazzi, Laura Di Lodovico et al.
5 citations
A systematic review of 31 studies involving 2639 participants found that 12 studies reported a significant decrease in craving for alcohol, opioids, cocaine, or tobacco after psychedelic use. However, all but two studies had moderate to high risk of bias due to methodological issues, so the promising anti-craving effects must be interpreted cautiously. The review highlights the need for larger, well-controlled trials to better understand psychedelics' effects on craving, a core symptom of substance use disorders and a predictor of relapse.
International Journal of Mental Health and Addiction
April 24, 2025
Jérémie Richard, Jeremy Scott, Sandeep M. Nayak et al.
3 citations
No Summary
Scientific Reports
February 25, 2026
Albert Garcia-Romeu, Gideon P. Naudé, Alison W. Rebman et al.
2 citations
An estimated 10–20% of Lyme disease patients develop post-treatment Lyme disease (PTLD), a chronic syndrome with no established treatments. In an open-label pilot study of 20 participants with PTLD, two sessions of psilocybin (15 mg then 15 or 25 mg) with psychological support led to significant improvements in symptom burden and quality of life from enrollment through one month after the second dose, with benefits sustained at six months. At six months, general PTLD symptom burden decreased 40% from baseline, and mental and physical quality-of-life scores improved 13%. Mood, fatigue, sleep, and pain also improved. No serious adverse events occurred; common side effects were transient hypertension, headache, and tachycardia. The findings suggest psilocybin-assisted treatment is feasible and well-tolerated, warranting further research.
NPP Digit Psychiatry Neurosci
August 20, 2025
Albert Garcia-Romeu
2 citations
The term 'hallucinogen' is a misleading label for drugs like ketamine, MDMA, and psilocybin, which rarely cause true hallucinations (false perceptions believed to be real). Instead, they produce perceptual alterations such as pseudo-hallucinations, synaesthesia, and illusions, along with changes in thinking, emotions, sense of time, self, and bodily awareness. These subjective effects—not hallucinations—are more often linked to therapeutic benefits. Historically, terms like psychotomimetics, phantastica, and psychedelics have been used, reflecting the complex mind-altering effects of these substances.
The International journal on drug policy
July 1, 2026
Alex K Gearin, I Glenn Cohen, Albert Garcia-Romeu
1 citation
The revival of psychedelic medicalization is often presented as a story of scientific legitimacy and neurotherapeutic promise, but the sensitivity of psychedelics to environmental conditions has encouraged research on music, therapy, setting, and other contextual factors. This article examines how regulation actively shapes atmospheres of consumption for substances that alter affective and sensory perception. Debates over drug-centric versus therapy-centered models are situated within the broader issue of how law shapes contexts and settings of psychedelic consumption.
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%).
European journal of trauma & dissociation = Revue europeenne du trauma et de la dissociation
September 1, 2025
Shahar Almog, Albert Garcia-Romeu, Kathryn A Walker et al.
1 citation
People with post-traumatic stress disorder (PTSD) who also have depression, anxiety, and sleep problems reported that ketamine treatment improved multiple PTSD symptoms, based on a survey of 202 real-world patients. Before starting ketamine, those with PTSD had more severe depression, anxiety, and sleep disturbance than those without PTSD, but after treatment their scores were no different, indicating they responded equally well. Most PTSD patients also received psychotherapy, but similar improvements occurred in those who did not. Patients described ketamine as allowing them to reprocess trauma and improve a range of symptoms.