This single-blind, cross-over study (n=28) using MRI in healthy participants found that psilocybin (18.2mg/70kg) significantly decreased cerebral blood flow (CBF) and internal carotid artery (ICA) diameter. In contrast, ketanserin (20mg) had no significant effect. This finding suggests an asymmetric 5-HT2AR modulatory effect on CBF and provides the first in vivo human evidence of psilocybin-induced ICA constriction.
MedRvix
September 2024
Cited by 0
This randomized, double-blind, placebo-controlled, crossover study (n=16) investigates the dose-dependent acute effects, pharmacokinetics, and mechanism of action of mescaline (100-800mg; 5x) in healthy subjects. It finds that mescaline induces dose-dependent subjective effects, increases blood pressure and heart rate, and has dose-proportional pharmacokinetics, with effects primarily mediated by 5-HT2A receptors as demonstrated by ketanserin co-administration.
Translational Psychiatry
September 2024
Cited by 0
This open-label trial (n=15) evaluates the efficacy and safety of psilocybin (25mg) in veterans with severe treatment-resistant depression (TRD). It finds that 60% of participants met response criteria and 53% met remission criteria at 3 weeks post-treatment, with 47% maintaining response and 40% maintaining remission at 12 weeks.
Journal of Affective Disorders
September 2024
Cited by 0
This randomized, double-blind, placebo-controlled study (n=68) assesses the prosocial, entactogen effects of ketamine (35mg/70kg) in participants with treatment-resistant depression (TRD). Ketamine increased pleasure from social interactions and helping others, lasting for one week post-treatment. In a rodent experiment, ketamine-treated rats showed increased protective behaviour towards their cage mates, indicating entactogen effects.
American Journal of Psychiatry
July 2024
Cited by 2
This double-blind, placebo-controlled study (n=40) investigates the effect of DMT-harmine ('pharmahuasca') on meditative states during a 3-day retreat with experienced meditators. It finds that participants who received DMT-harmine reported greater mystical-type experiences, non-dual awareness, and emotional breakthrough during acute effects, as well as greater psychological insight one day later, compared to the placebo group.
Journal of Psychopharmacology
September 2024
Cited by 0
This open-label single ascending dose Phase I trial (n=25) determines the maximum tolerated dose (MTD) of oral pharmaceutical-grade harmine (component of ayahuasca brew) in healthy adults. It finds that doses <189mg/70kg can be administered with minimal or no adverse events, while doses >189mg/70kg are associated with vomiting, drowsiness, and limited psychoactivity.
Journal of Psychopharmacology
September 2024
Cited by 0
This re-analysis of a single-blind study (n=17) investigates the role of the autonomic nervous system in DMT-induced peak experiences (20mg, iv). It finds that balanced activity between the "fight-or-flight" and "rest-and-digest" systems (sympathovagal coactivation) is linked to stronger feelings of spirituality and insight during DMT sessions and improved well-being two weeks later. The study also notes that a person's nervous system (sympathovagal) balance before taking DMT can predict how insightful their experience will be.
Journal of Psychopharmacology
September 2024
Cited by 0
This comparative study (n=56) investigates the relationship between antidepressant effects and acute drug effects of LSD and psilocybin in 28 patients undergoing psychedelic-assisted therapy (PAT) in Switzerland and 28 healthy volunteers from a randomized, double-blind crossover trial. The study finds similar ratings of overall drug effect and mystical experience across groups, but lower ratings of ego dissolution in patients. It identifies relaxation during PAT sessions as the greatest predictor of antidepressant outcomes.
Journal of Psychopharmacology
September 2024
Cited by 1
This case study (n=1) finds that a single low dose of 5 µg (0.38µg/kg) of 1cp-LSD on a 13-year-old female dog with a history of separation-related behavioural problems significantly reduced anxiety after two hours. No adverse effects or signs of a psychedelic experience were observed during the 5.5-hour trial.
Veterinary Research Communications
September 2024
Cited by 0
This 6-month follow-up of a Phase II, double-blind, randomized controlled trial (n=59) finds sustained improvements in depressive symptoms for both psilocybin therapy (PT) and escitalopram treatment (ET) for moderate-to-severe major depressive disorder (MDD). PT shows greater improvements in psychosocial functioning, meaning in life, and psychological connectedness compared to ET at the 6-month follow-up.
EClinicalMedicine
September 2024
Cited by 0
This open-label study (n=4) investigated the effects of low-dose oral psilocybin (5-10mg) with psychological support in patients with chronic short-lasting unilateral neuralgiform headache attacks (SUNHA). The study aimed to assess cognitive effects, safety, tolerability, and impact on headache severity and frequency, but was terminated early due to recruitment difficulties.
Headache
September 2024
Cited by 0
This survey (n=319) of psychedelic users measured personality traits using the Ten-Item Personality Inventory (TIPI) and a simplified Risk Taking Index (RTI). The study finds participants scored higher than norms on all Big Five traits except Extraversion, and on all dimensions of risk-taking. Personality structure was linked to psychedelic experience characteristics such as feelings of fear, love, peace, and perceptions of contact with transcendent forces.
Journal of Psychoactive Drugs
November 2020
Cited by 24
This retrospective survey (n=143) of Amazon Mechanical Turk participants who self-administered psilocybin identifies factors related to mystical experiences (MEs) and challenging experiences. The study finds a state of surrender predicts MEs, while preoccupation predicts challenging experiences, explaining 66% and 56% of the variance in ME and dread scores, respectively. Mystical experiences during the session also relate to long-term positive changes.
Psychology of Consciousness Theory Research and Practice
March 2019
Cited by 56
This mixed-design study (n=48) finds significant increases in agreeableness and reductions in neuroticism post-ayahuasca administration (n=24), sustained at 6-month follow-up, with trait level increases in openness also observed at follow-up. The study also reports an association between greater perceived mystical experience and increased reductions in neuroticism.
Psychopharmacology
July 2020
Cited by 47
This double-blind, placebo-controlled, crossover trial (n=28) finds that LSD (100μg), d-amphetamine (40mg), and MDMA (125mg) reduced network integrity in healthy volunteers. LSD uniquely reduced default-mode network integrity and showed more pronounced effects on network segregation and seed-based connectivity compared to amphetamines.
Molecular Psychiatry
September 2024
Cited by 0
This cross-sectional survey study (n=863) of meditators with psychedelic experience finds that most participants (73.5%) perceive psychedelic use as beneficial to their meditation practice. The study identifies four key predictors of this perceived benefit: regularity of psychedelic use, intention setting during use, agreeableness, and exposure to DMT.
MedRvix
August 2024
Cited by 0
This online survey (n=1967) examines the set and setting of psychedelic use and its outcomes concerning users' well-being and personality traits. It finds that individuals with low well-being and higher neuroticism scores are more likely to experience positive mood changes after using LSD, psilocybin, or MDMA. However, they also report a higher likelihood of adverse side effects.
Drug Science, Policy and Law
January 2020
Cited by 16
This health economics study (n=14.8 million) estimates the potential demand for psilocybin-assisted therapy (PSIL-AT) for major depressive disorder (MDD) and treatment-resistant depression (TRD) in the United States. It finds that 24% (lower-bound; 2.2m), 56% (mid-range; 5.1m), and 62% (upper-bound; 5.6m) of patients with MDD or TRD may be eligible for PSIL-AT, with variance largely influenced by exclusion criteria and comorbidity considerations.
Psychedelics
September 2024
Cited by 0
This re-analysis of an RCT (n=80) finds no effect of LSD microdosing (10µg, x14) on creativity in healthy adult males. Participants received either LSD or placebo every third day for six weeks, with creativity assessed using multiple tests at baseline, during acute dosing, and after the six-week regimen.
Psychopharmacology
September 2024
Cited by 0
This pooled analysis of nine double-blind, placebo-controlled, cross-over studies (n=213) investigates predictors of LSD effects in healthy subjects. It finds that LSD dose is the most influential predictor, with pre-drug mental states, personality traits, and previous hallucinogen experiences also significantly affecting the subjective experience.
Translational Psychiatry
September 2024
Cited by 0
This systematic review (2024) and meta-analysis (s=12) examines the therapeutic effects of single-dose and two-dose psilocybin administration on depressive symptom severity in MDD and TRD patients. It finds that psilocybin is highly effective in reducing depressive symptoms in both patient groups, with two-dose treatments potentially offering more pronounced and lasting effects (but no statistically significant difference).
Brain Sciences
August 2024
Cited by 0
This cell-based study investigates the role of serotonin receptors in the claustrum's response to psychedelic drugs. It finds that the claustrum is rich in 5-HT2C receptors on glutamatergic neurons and that serotonin and the psychedelic DOI have opposite effects on synaptic signalling, both mediated by 5-HT2C receptors rather than 5-HT2A receptors as previously thought.
Progress in Neurobiology
September 2024
Cited by 0
This review (2024) examines the acute subjective effects of classic psychedelics, their relationship to risks and therapeutic benefits, and the current limitations in measuring these effects. It discusses existing measures, their construct validity, and predictive value for outcomes, while proposing recommendations for improving conceptualization and measurement in future research.
Nature Reviews Psychology
September 2024
Cited by 1
This systematic review (2024) and meta-analysis (s=214, n=3504) examines adverse events (AEs) associated with classic psychedelics in clinical or research settings. It finds that serious AEs were rare, occurring in approximately 4% of participants with preexisting neuropsychiatric disorders, while no serious AEs were reported in healthy participants.
JAMA Psychiatry
September 2024
Cited by 1
This double-blind, randomized, placebo-controlled, crossover study (n=24) compares the acute effects of MDMA, S-MDMA, R-MDMA (the left and right-handed parts of MDMA), and placebo in healthy participants. It finds that S-MDMA (125 mg) induced stronger subjective effects and higher increases in blood pressure than R-MDMA and racemic MDMA while also increasing plasma prolactin, cortisol, and oxytocin more significantly. The study also notes differences in elimination half-lives and metabolite concentrations between the different forms of MDMA.
Neuropsychopharmacology
August 2024
Cited by 0
This pre-print, open-label study (n=10) investigates the effects of single-dose psilocybin (25mg) therapy in adults with severe alcohol use disorder (AUD). It finds significant reductions in alcohol consumption, craving, and increases in self-efficacy over 12 weeks following treatment despite notable between-participant pharmacokinetic variations.
Research Square
August 2024
Cited by 0
This double-blind, randomized, placebo-controlled study (n=39) examines the effects of a single low dose of LSD (26µg) on event-related potentials during an emotional face oddball task. It finds that LSD significantly reduced the amplitude of N170 ERP to neutral faces and P300 ERP to neutral and happy faces, suggesting differential effects on brain responses to social and emotional information.
Psychedelic Medicine
August 2024
Cited by 0
This review (2024) examines the potential role of the gut microbiome in mediating the effects of psychedelic drugs on behaviour. It argues that the current understanding of psychedelic mechanisms, focused primarily on serotonin 2A receptor agonism, is incomplete and needs to incorporate the gut microbiome and its (two-way) interactions with the brain.
Pharmacological Research
August 2024
Cited by 0
This survey (n=68) of researchers and clinicians involved in MDMA-assisted therapy (MDMA-AT) examines opinions on clinical practices, training, and regulation. The study finds broad support for training standardization and highlights challenges in the national (European) approval process. Experts emphasize the importance of science-informed policy, active regulatory involvement, and international cooperation to integrate MDMA-AT into the European mental healthcare system, particularly for treating PTSD.
European Journal of Psychotraumatology
August 2024
Cited by 0
This theoretical review examines how psychedelics may lead to false insights and beliefs by connecting experimental work on false memories with insights under psychedelics using the active inference framework. It suggests that psychedelics increase the quantity and intensity of insights, which could include false beliefs, and proposes future research directions to minimize such risks while maximizing therapeutic potential.
Communications Psychology
August 2024
Cited by 0
Find Psychedelic Papers
Find all relevant psychedelic research papers in our ever-growing database. Here we cover and connect the latest research and seminal papers. From early open-label psychedelic studies with healthy volunteers to large-scale double-blind, placebo-controlled trials.
We have not only indexed over 2000 papers but have added additional contexts such as type of study, a compound studied, which paper it’s related to, the trial associated with a study, and over 30 more variables.
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