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.
Journal of Psychopharmacology
March 1, 2022
Peter S. Hendricks, Heith Copes, Neiloufar Family et al.
8 citations
In a proof-of-concept study with 31 healthy participants given 50 to 100 µg of LSD, most felt safe throughout the experiment, attributing their comfort to the study structure and support from attendants, which allowed them to let go and immerse themselves. A minority initially worried about having a challenging experience, but those concerns lessened over time. Participants reported transcendent, mystical-type experiences typical of classic psychedelics, with nearly half noting the important role of music during the drug's acute effects. They endorsed the clinical utility of LSD in controlled environments, believing it is safe and could help others. Findings suggest this scalable intervention paradigm is feasible and warrants further research with clinical populations.
Psychedelic Med (New Rochelle)
March 13, 2023
Peter S. Hendricks, Charles D. Nichols, Kathryn A. Cunningham et al.
7 citations
A roundtable discussion among experts traces the history, current state, and future directions of psychedelic medicine. Participants review the early research era of the mid-20th century, the subsequent decades of prohibition, and the recent resurgence of clinical trials exploring psychedelics for mental health conditions. The conversation highlights therapeutic applications of substances such as psilocybin and MDMA, emphasizing their potential to treat depression, PTSD, and addiction. Experts also address challenges including regulatory hurdles, the need for trained therapists, and the importance of integrating these treatments into mainstream healthcare. The discussion concludes with cautious optimism about the field's trajectory.
Journal of Psychopharmacology
October 1, 2022
Grant Jones, Jocelyn A. Ricard, Peter S. Hendricks et al.
7 citations
Lifetime use of MDMA (ecstasy) is associated with better self-reported physical health, including lower risks of overweight/obesity, heart conditions, cancer, hypertension, and diabetes, along with higher odds of reporting good overall health. These associations emerged from a large, nationally representative U.S. sample, controlling for potential confounders. The findings suggest protective links between ecstasy use and various physical health markers, but the authors call for longitudinal studies and clinical trials to confirm causality.
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.
Psychedelic Med (New Rochelle)
September 13, 2023
Peter S. Hendricks, Charles D. Nichols
6 citations
A survey of psychedelic researchers found that a substantial majority have personal experience with psychedelics, and many report that this experience positively influences their professional work, including enhancing empathy and insight. The study highlights that personal use is common in the field, yet often remains an unspoken topic, suggesting it may shape research perspectives and practices.
Journal of Psychoactive Drugs
August 31, 2023
Haley Maria Dourron, Heith Copes, Agasthya Vedre-Kyanam et al.
6 citations
The subjective experiences of diphenhydramine (DPH) misuse, based on 32 first-hand YouTube accounts analyzed with thematic analysis, are predominantly unpleasant, featuring alterations in most sensory modalities, confusion, and dysphoria. Positive effects were rare and often overshadowed by negative aspects. Video makers frequently warned against misuse and occasionally reported adverse post-acute effects. Despite the prevalence of adverse experiences, patterns of repeated misuse were sometimes discussed. Motives for misuse included accessibility, affordability, and legality. The findings suggest DPH misuse can produce substantial, often distressing psychoactive effects that share phenomenological overlap with experiences produced by psychosis.
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.
EClinicalMedicine
October 1, 2020
Peter S. Hendricks
5 citations
An open-label pilot study demonstrated the feasibility, safety, and potential efficacy of psilocybin-assisted group therapy for demoralization in older long-term AIDS survivor (OLTAS) men, a marginalized population with high rates of comorbid mental health conditions. The group therapy paradigm is innovative because classic psychedelic treatments typically rely on individual sessions, raising scalability concerns. Half the sample met criteria for a comorbid condition such as generalized anxiety disorder, panic disorder, or borderline personality disorder. The findings are not conclusive; future randomized placebo-controlled trials with larger samples are needed to more definitively inform safety and effectiveness.
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.
Front Psychiatry
December 9, 2025
Haley Maria Dourron, Heith Copes, Daniel H. Grossman et al.
3 citations
People diagnosed with non-affective psychotic disorders who used psychedelics reported a mix of positive and negative effects. Common challenges during the acute experience included transient anxiety, sometimes leading to brief hospitalizations. Some participants described psychosis-specific experiences such as reduced self-stigma and insight into their hallucinations and delusions. Perceived long-term benefits varied widely, with some reporting lasting positive changes and others noting negative effects or no lasting impact. The findings suggest psychedelics may pose both risks and potential benefits for this population, highlighting the need for careful safety trials.
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.
Int J Drug Policy
December 13, 2025
Michelle Olofsson, Walter Osika, Simon B. Goldberg et al.
2 citations
A cross-sectional survey of 3,168 U.S. adults with lifetime psychedelic use found that most (87.9%) reported no difficulties. Among those who did, 6.4% experienced post-acute difficulties lasting more than one day, and 1.3% for more than one year. The most common difficulties were general anxiety, negative changes in self-concept, and social disconnection. Childhood adversity was associated with higher odds of psychedelic-related difficulties: individuals with 2, 3, or 4 or more adverse childhood experiences had roughly double to nearly triple the odds of difficulties compared to those with none. Those with 4 or more ACEs also had higher odds of difficulties persisting beyond one day or one week.
J Psychiatr Res
March 17, 2025
Otto Simonsson, Sankalp Chaturvedi, Peter S. Hendricks et al.
2 citations
Psychedelic use is linked to increases in weekly mindfulness and loving-kindness or compassion meditation practice, especially among people new to psychedelics or meditation. In a longitudinal study of 13,012 US adults aged 18–50, with 7,484 completing follow-up and 336 reporting psychedelic use during the two-month study, those who used psychedelics showed greater gains in meditation days. Among psychedelic users, higher baseline trait mindfulness and self-compassion predicted less severe challenging experiences and lower odds of psychedelic-related thoughts or attempts of self- or other-harm. However, for those already meditating, psychedelic use was associated with more meditation-related difficulties and impairments.
November 22, 2024
Haley Maria Dourron, Melissa Bradley, Peter S. Hendricks
1 citation
preprint
Emergency room visits involving hallucinogens are associated with a 21.32 times greater risk of later being diagnosed with a schizophrenia spectrum disorder. The authors discuss implications for developing psychedelics as medicines, but important distinctions are highlighted.
Psychedelic Med (New Rochelle)
December 13, 2023
David E. Nichols, Peter S. Hendricks, Charles D. Nichols
1 citation
The authors argue that the term 'psychedelic' is being applied so broadly in recent scientific literature that it risks losing its meaning. They respond to two other articles, contending that not all altered states of consciousness or therapeutic experiences qualify as psychedelic. The piece calls for more precise terminology to preserve the distinctiveness of classic psychedelics and their effects, warning that overextension could dilute scientific classification and hinder research into specific mechanisms and therapeutic applications.
Psychedelic Medicine
June 22, 2026
Otto Simonsson, Peter S. Hendricks, Walter Osika et al.
Naturalistic psychedelic use on politically salient dates like the Fourth of July may shift support for partisan violence in directions tied to the event's political meaning. In a longitudinal observational study of 21,990 US adults, 12,345 completed follow-up surveys; 505 reported psychedelic use during the two-month period. Those whose most intense psychedelic experience occurred on the Fourth of July showed decreased support for partisan violence, with a similar pattern for the Trump assassination attempt date. Conversely, experiences on national party convention dates or closer to Election Day were associated with increased support for partisan violence. The broader sociocultural context appears to modulate these outcomes.
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.
BMJ Open
August 1, 2025
Nicky J. Mehtani, B. Anderson, Irina Alexander et al.
Methamphetamine use disorder (MeUD) has no FDA-approved pharmacotherapies and is linked to poor neurological, psychiatric, and cardiovascular outcomes, especially among low-income populations, while also increasing risks for sexually transmitted infections. The Ketamine-Assisted Recovery (KARE) trial is an open-label pilot study enrolling 12 to 24 Medicaid- or Medicare-insured adults with moderate-to-severe MeUD and HIV risk factors. Participants will receive three intramuscular ketamine sessions (0.50-0.75 mg/kg) combined with seven motivational enhancement therapy sessions over five weeks. The study will assess feasibility, acceptability, tolerability, safety, and potential mechanisms such as psychological flexibility, laying groundwork for future randomized trials.
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.