Neuropharmacology
June 5, 2018
Matthew W. Johnson, Roland R. Griffiths, Peter S. Hendricks et al.
348 citations
Psilocybin, like other classic psychedelics that activate 5-HT2A receptors, has limited reinforcing effects and only marginal, transient non-human self-administration, indicating low abuse potential. Illicit use of psilocybin-containing mushrooms is occasional, with a few lifetime uses being typical. Potential harms include dangerous behavior in unprepared, unsupervised users and exacerbation of mental illness in those predisposed to psychotic disorders, but the scope of use and associated harms are low compared to prototypical abused drugs. The medical model mitigates these risks through dose control, patient screening, preparation, follow-up, and session supervision. If approved as a medicine, the review suggests that Schedule IV placement under the US Controlled Substances Act may be appropriate.
Journal of Psychopharmacology
October 17, 2017
Peter S. Hendricks, Michael Crawford, Karen L. Cropsey et al.
91 citations
Lifetime use of classic psychedelics, including psilocybin, is associated with lower odds of recent larceny/theft, assault, and arrests for property or violent crimes among over 480,000 U.S. adults surveyed from 2002 to 2014. In contrast, illicit use of other drugs generally increased the odds of these criminal behaviors. Lifetime classic psychedelic use was linked to higher odds of drug distribution, similar to other substances. The findings suggest a potential protective effect of psilocybin against antisocial criminal behavior and support further clinical research in forensic settings.
Journal of Psychopharmacology
March 9, 2021
Otto Simonsson, James Sexton, Peter S. Hendricks
75 citations
People who have used a classic psychedelic at least once in their lifetime report better overall health and are less likely to be overweight or obese, based on data from over 171,000 U.S. adults. The study also found a trend toward lower odds of having a heart condition or cancer in the past year among those who had used a classic psychedelic. The findings suggest that classic psychedelics may be linked to better physical health, but the authors note that further research is needed to determine whether the relationship is causal and to explore possible mechanisms.
Scientific Reports
July 13, 2021
Otto Simonsson, Walter Osika, Robin Carhart‐Harris et al.
54 citations
Lifetime use of classic psychedelics is associated with lower odds of heart disease and diabetes. Analyzing data from the National Survey on Drug Use and Health (2005–2014), people who had ever tried a classic psychedelic had 23% lower odds of past-year heart disease and 12% lower odds of past-year diabetes. The associations persisted after adjusting for other factors. The authors suggest classic psychedelic use might benefit cardiometabolic health but call for more research on causal pathways.
Frontiers in Psychiatry
February 11, 2020
James D. Sexton, Charles D. Nichols, Peter S. Hendricks
45 citations
Lifetime use of classic tryptamine psychedelics is linked to lower odds of past-month psychological distress and past-year suicidal thinking, while lifetime use of novel phenethylamines is linked to higher odds of past-year suicidal thinking and planning. These findings, from a large nationally representative U.S. survey, suggest that classic tryptamines may hold greater therapeutic potential than novel phenethylamines, which may pose risks for harm. No significant associations were found for other psychedelic classes.
Hypertension
March 8, 2021
Otto Simonsson, Peter S. Hendricks, Robin Carhart‐Harris et al.
36 citations
Adults who had used a classic psychedelic at least once in their lifetime had 14% lower odds of hypertension in the past year, after adjusting for confounders. The association was strongest for tryptamine psychedelics (DMT, ayahuasca, psilocybin), which were linked to 20% lower odds of hypertension. No significant association was found for LSD or mescaline. The authors note these findings are correlational and call for randomized controlled trials to test causal effects.
Neuropharmacology
May 13, 2022
Cynthia E. Ortiz, Haley Maria Dourron, Noah W Sweat et al.
26 citations
Psilocybin-facilitated psychotherapy may be effective across many mental health conditions, but vulnerable populations, who carry a disproportionate mental health burden, have been largely excluded from clinical research. This report highlights the need to include these groups in studies, considering their problematic historical context and differential experiences with psychedelics. It offers actionable recommendations for future research, such as improved recruitment strategies, careful communication of subjective effects, building therapeutic alliance, multicultural competence, and flexible study designs. The authors call for expanded and improved research in this rapidly advancing field.
Journal of Psychopharmacology
March 1, 2022
Neiloufar Family, Peter S. Hendricks, Luke T. J. Williams et al.
23 citations
LSD doses of 50, 75, and 100 micrograms are tolerable and safe in healthy adults when administered in a novel group-based intervention paradigm with one attendant per participant. Thirty-two adults (mean age 28.8 years) received LSD or placebo across open-label and double-blind designs. No serious adverse events occurred; 28% of participants reported at least one mild expected adverse event and one moderate event. Peak blood plasma levels appeared 1.2 to 2 hours after administration, with an apparent half-life of 2.8 to 4.3 hours. LSD produced greater subjective effects than placebo, including mystical-type experiences. Further research is needed in clinical populations.
Journal of Psychopharmacology
November 30, 2016
Richard C. Shelton, Peter S. Hendricks
14 citations
No Summary
Journal of Drug Issues
August 30, 2019
Blake Beaton, Heith Copes, Megan Webb et al.
13 citations
People who microdose classic psychedelics such as LSD and psilocybin do not excuse their practice but instead justify it using six main strategies: denying that it causes harm, claiming it helps sustain themselves, pursuing self-fulfillment, appealing to normality, citing loyalty to valued groups, and emphasizing their knowledgeable. These justifications help align their actions with societal expectations. The findings come from interviews with 30 individuals who had microdosed.
Nature Mental Health
May 1, 2025
Daniel H. Grossman, Kevin R. Madden, Nicky J. Mehtani et al.
10 citations
Socioeconomic status (SES) strongly affects mental health outcomes and treatment access, but its reporting in psychedelic-assisted therapy trials is inadequate. A systematic review of 98 articles (49 primary trials and 49 secondary analyses) from 2006 to 2024 found that only 12% of primary trials reported participant income data, and 31% reported educational attainment. In US-based trials, participants had markedly higher SES than the general population: 93% had some college education (versus 62% nationally), and median incomes in major trials substantially exceeded the national median for all workers. Non-US trials showed variable patterns. This underreporting and evidence of socioeconomic disparities highlights an urgent need for standardized SES reporting and strategies to improve socioeconomic diversity in psychedelic-assisted therapy research.
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.
Scientific Reports
August 2, 2024
Jennifer Mitchell, Nicky J. Mehtani, Mallory O. Johnson et al.
9 citations
HIV-related shame predicts substance use and poor antiretroviral adherence among people with HIV, hindering national epidemic-ending goals. In a pilot clinical trial with 12 participants, psilocybin-assisted group therapy produced a large decrease in HIV-related shame, with a median reduction of 5.5 points on the HIV and Abuse Related Shame Inventory from baseline to 3-month follow-up. However, two participants experienced a paradoxical worsening of sexual abuse-related shame after psilocybin, raising concerns about its use in patients with trauma. These preliminary results suggest potential for addressing HIV-related shame but highlight cautions.
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.
Journal of Psychoactive Drugs
February 10, 2024
Alyssa F. Harlow, Peter S. Hendricks, Adam M. Leventhal et al.
6 citations
Among 2,396 young adults aged 18-22 in Southern California surveyed in 2018-2019, 12% had heard of microdosing psychedelics and 3% had ever tried it. Of those aware of microdosing, 79% correctly defined it as taking a much lower than standard dose, but 15% mistakenly thought it meant a standard dose. Psilocybin was the most commonly microdosed drug (70%), followed by LSD (57%). About 18% of those who microdosed reported using doses far higher than a typical microdose. Factors associated with having ever microdosed included white race, male/masculine gender identity, bisexual identity, past 6-month other drug use, greater ADHD symptoms, mindfulness, and sensation-seeking. The findings suggest microdosing merits attention to prevent misperceptions and potential harms while exploring therapeutic uses.
Drug Science Policy and Law
January 1, 2023
Brian S. Barnett, Noah Wiles Sweat, Peter S. Hendricks
6 citations
A person with red-green color blindness (mild deuteranomalia) self-administered the Ishihara color vision test before and after taking 5 grams of dried psilocybin mushrooms. Partial improvement in color vision peaked at 8 days and lasted at least 16 days after taking psilocybin, though later observations were confounded by additional substance use. The improvement extended beyond the acute drug effect, even though color blindness is typically a genetic condition. The authors call for systematic research to confirm these findings and understand the mechanism.
Expert review of neurotherapeutics
January 1, 2023
Emmanuelle A. D. Schindler, Peter S. Hendricks
5 citations
Most current psychedelic research targets depression and substance use disorders, but reports also indicate benefits for headache disorders and chronic pain. This perspective reviews conventional treatments for these conditions and describes historical, recent, and ongoing investigations of psychedelics' therapeutic effects, including the first two clinical trials of psilocybin in headache disorders and case reports of psilocybin mushroom self-administration in chronic pain patients. It highlights challenges when applying the standard psychedelic-assisted psychotherapy model—featuring larger doses, emphasis on subjective effects, and required adjunctive psychotherapy—to headache and chronic pain disorders. Flexibility in protocols is needed to evaluate different treatment paradigms and mechanisms.
JAMA Network Open
May 7, 2026
Peter S. Hendricks, Sara Lappan, Richard C. Shelton et al.
4 citations
A single 25 mg dose of psilocybin, combined with psychotherapy, led to a higher percentage of cocaine-abstinent days, a greater likelihood of complete abstinence, and a longer time before the first cocaine lapse over 180 days compared with an active placebo (100 mg diphenhydramine) in a randomized, quadruple-blind trial. Among 40 participants with cocaine use disorder, 33 were men, 33 were Black, and most had low income. Psilocybin appeared safe, with no serious adverse events, and may offer a treatment for cocaine use disorder in underrepresented populations.
Journal of Drug Issues
August 22, 2024
Heith Copes, Andrew Hochstetler, J. Ragland et al.
3 citations
People who used peyote in a naturalistic setting reported four core areas of change: reduced drug and alcohol misuse, new perspectives on life, improved mental health, and improved physical health. The duration of change varied by type. Participants attributed these changes to an improved ability to endure challenges, rewiring of the brain, and connecting with spiritual selves. The findings suggest specific areas for research on peyote and psychedelics in clinical and therapeutic settings.
October 28, 2016
Peter S. Hendricks, Charles S. Grob
3 citations
Psychedelics like psilocybin, ayahuasca, and lysergic acid diethylamide have shown promise in altering perception and improving mental health. In a study involving 100 participants, 60% reported significant reductions in anxiety and depression after using these substances. Notably, mescaline also demonstrated potential therapeutic effects, with 40% of users experiencing enhanced emotional well-being. The influence of these hallucinogens on neurotransmitter receptors may explain their behavioral impacts, making them valuable tools in modern psychiatry and psychology for addressing various mental health disorders.
International Journal of Mental Health and Addiction
March 17, 2026
Haley Maria Dourron, Melissa K. Bradley, Heith Copes et al.
Interviews with 19 people diagnosed with non-affective psychotic disorders who had used psychedelics revealed that, while some similarities exist in altered thinking and meaning attribution, most participants reported that psychedelic experiences did not closely resemble their psychosis. Sensory alterations, emotional experience, sense of control, and self-experience were points of contrast. When asked which drug most resembled their psychotic symptoms, the majority endorsed cannabis, followed by dissociative anesthetics and stimulants. The findings suggest that psychedelics may not accurately model many symptoms of psychosis and that interpreting psychedelic experiences as broadly psychosis-like may be misleading.
Scientific Reports
January 28, 2026
Nicholas A. Carlisle, Otto Simonsson, Sarah Maccarthy et al.
About one in five people who have used psychedelics report at least one major life change they attribute to the experience. Common changes involve relationships (6.9%), diet and exercise (6.2%), quitting alcohol, tobacco, or other substances (5.5%), and religious beliefs (5.5%). In a larger, more diverse sample, higher religiosity, younger age, and greater lifetime psychedelic use were strongly associated with reporting such changes. The findings suggest that major life changes after psychedelic use are not rare and may vary by demographic factors, but more longitudinal research is needed to understand their persistence, valence, and health impact.
Psychedelic Medicine
December 19, 2025
Amanda Husein, Madalynn Traylor, M. Frances Vest et al.
Most Louisiana psychiatrists surveyed are open to psilocybin's medical use if backed by regulation. 82% reported some knowledge of psilocybin; 86% believed it should be researched for medicinal value; 71% would prescribe it if proven beneficial for a patient's illness. 57% thought it should be a first-line treatment for certain conditions, while 73% believed it should be used only after other treatments failed. The 10.5% response rate limits generalizability. The findings suggest a need for educational programs on psychedelics to inform clinical decisions.
Sociology Compass
February 26, 2025
Heith Copes, Haley Copeland, Lynne M. Vieraitis et al.
People accused of cultural appropriation often resist the label by either denying that cultural appropriation exists or by claiming that their own actions are respectful and therefore not appropriative. An ethnographic study of individuals attending peyote ceremonies—a sacred Native American practice—in a Southern U.S. state found that participants used these two strategies to maintain a positive identity and avoid stigma. Those who denied appropriation argued that peyote is for everyone, while those who acknowledged appropriation as a concept insisted that their respectful conduct exempted them from being appropriators. The findings highlight how broader narratives help people minimize accusations of harm.