Journal of Psychopharmacology
December 17, 2021
Josephine Marschall, George Fejer, Pascal Lempe et al.
69 citations
In a double-blind, placebo-controlled, within-subject crossover study, psilocybin microdosing (a sub-hallucinogenic dose taken every third day) did not alter emotion processing, symptoms of anxiety or depression, or self-reported interoceptive awareness compared with placebo. Exploratory analyses showed that symptoms of depression and stress were significantly reduced in the first block compared with baseline, but participants broke blind in the second block, and there was no effect of expectations. The authors call for further research in a substance-naïve population with clinical-range anxiety and depressive symptoms to substantiate potential beneficial effects.
Drug Testing and Analysis
October 29, 2020
Klára Gotvaldová, Kateřina Hájková, Jan Borovička et al.
69 citations
Psilocybin, psilocin, baeocystin, norbaeocystin, and aeruginascin are tryptamines structurally similar to serotonin. Psilocybin and its active metabolite psilocin are known for psychoactive effects and occur in most Psilocybe fungi. Freshly cultivated Psilocybe cubensis fruit bodies were used to monitor stability under various storage and processing conditions. Mycelium and individual parts (caps, stipes, basidiospores) were examined via ultra-high-performance liquid chromatography-mass spectrometry. No tryptamines were detected in basidiospores; only psilocin was present at 0.47 wt.% in mycelium. Stipes contained about half the tryptamine alkaloids (0.52 wt.%) compared to caps (1.03 wt.%), but results were not statistically significant due to high variability. Highest degradation occurred in fresh mushrooms stored at -80°C; lowest decay in dried biomass stored in dark at room temperature.
Psychopharmacology
April 30, 2021
Michiel van Elk, George Fejer, Pascal Lempe et al.
53 citations
People who take small, non-hallucinogenic doses of psilocybin (microdosing) report feeling more awe when watching videos of funny animals and moving objects compared to when they take a placebo. However, about two-thirds of participants correctly guessed whether they had received psilocybin or placebo, suggesting that expectancy effects—rather than the drug itself—may explain the subjective benefits of microdosing. The study used a double-blind, placebo-controlled crossover design with a microdosing workshop and lab visits over several weeks.
International Journal of Molecular Sciences
November 15, 2022
Klára Gotvaldová, Jan Borovička, Kateřina Hájková et al.
50 citations
Wild mushrooms that contain psilocybin also carry several other tryptamine alkaloids in highly variable concentrations, making their effects unpredictable compared to pure psilocybin. Using ultra-high performance liquid chromatography with tandem mass spectrometry, researchers measured psilocybin, psilocin, baeocystin, norbaeocystin, and aeruginascin in 226 fruiting bodies from 82 collections across seven genera. Psilocybe species had the highest psilocybin and psilocin levels, but no tryptamines were detected in Psilocybe fuscofulva or Psilocybe fimetaria. For many species, concentrations of baeocystin, norbaeocystin, and aeruginascin were reported for the first time. The extreme variability in tryptamine content poses a risk of overdose for consumers and complicates interpretation of medicinal effects compared to chemically pure psilocybin.
Journal of Personalized Medicine
June 19, 2022
Vojtěch Viktorin, Inga Griškova-bulanova, Aleksandras Voicikas et al.
19 citations
Psilocybin, a psychedelic compound, reduces the brain's ability to synchronize its electrical activity at 40 Hz in response to auditory clicks. In a double-blind, placebo-controlled crossover study, 20 healthy volunteers received either psilocybin (0.26 mg/kg) or placebo. Measurements taken before and after ingestion showed that psilocybin decreased the phase-locking index and amplitude of the 40 Hz auditory steady-state response, and the degree of this reduction correlated with changes in cognition and affect. These findings support the role of gamma oscillations in cognitive processing and their disruption in psychosis.
Metabolites
November 12, 2021
Jitka Nykodemová, Anna Šuláková, Petr Palivec et al.
14 citations
The metabolism of the psychoactive compound 2C-B-Fly-NBOMe was investigated using three systems: human liver microsomes, the fungus Cunninghamella elegans, and live rats. Thirty-five phase I and nine phase II metabolites were identified. Major metabolic pathways include hydroxylation, O-demethylation, oxidative debromination, and N-demethoxybenzylation, followed by glucuronidation or N-acetylation. Human liver microsomes produced the most metabolites at highest concentrations. Two poly-hydroxylated metabolites appeared only in rat urine, while the fungus generated dehydrogenated, N-oxygenated, and dibrominated metabolites. These findings clarify how the body processes this substance, aiding understanding of its effects and potential toxicity.
British journal of pharmacology
January 1, 2022
Kristýna Štefková-mazochová, Hynek Danda, Wim Dehaen et al.
13 citations
Deschloroketamine (DCK), a structural analogue of ketamine sold as a recreational drug, was tested in Wistar rats to examine its pharmacokinetics, acute effects, and addictive potential. DCK rapidly entered the brain, with peak levels at 30 minutes and sustained high levels for 2 hours. It blocks NMDA receptors similarly to ketamine, with the S-enantiomer more potent. DCK stimulated locomotion, induced place preference (a sign of reward), and strongly disrupted prepulse inhibition (PPI). Locomotor stimulation faded faster than PPI disruption. S-DCK had stronger stimulatory effects than R-DCK, but both equally disrupted PPI. DCK's behavioral and addictive profiles resemble ketamine's, with a slightly slower clearance, matching its reported longer duration. These findings clarify risks of illicit DCK use.
Pharmacological reports : PR
June 16, 2025
Tereza Klučková, Marek Nikolič, Filip Tylš et al.
4 citations
In healthy individuals, psilocybin produces lasting positive effects regardless of previous psychedelic experience, repeated use, setting, sex, or occupation. In a double-blind, placebo-controlled crossover study with 40 participants (20 females, mean age 38), each received two doses of psilocybin (0.26 mg/kg) at least 56 days apart. Acute effects were moderate on the Altered States of Consciousness Scales, with mostly pleasant or fluctuating experiences and only one unpleasant session; all sessions ended positively or neutrally. Long-term effects, assessed by the Persisting Effects Questionnaire, were positive across all domains with negligible negative effects. Peak experiences ending in a positive mood strongly predicted favorable long-term outcomes, while challenging experiences did not cause adverse outcomes. These findings support psilocybin's psychological safety and repeated use in clinical trials.
Frontiers in pharmacology
January 1, 2023
Kateřina Syrová, Klára Šíchová, Hynek Danda et al.
4 citations
2C-B-Fly-NBOMe, a new psychoactive substance related to the psychedelic entactogen 2C-B, was studied in adult male Wistar rats. After injection, peak drug levels in blood serum occurred at 30 minutes (28 ng/ml) and in brain tissue at 60 minutes (171 ng/g), with the compound still detectable in the brain after 8 hours. The drug dose-dependently reduced locomotor activity and strongly disrupted the acoustic startle response, with a weaker effect on prepulse inhibition. It did not cause significant changes in body temperature. The overall profile resembles that of 2C-B and other NBOMe substances, suggesting slow brain penetration and inhibitory effects on motor performance and sensorimotor gating.
medRxiv
August 26, 2024
Tereza Klučková, Filip Tylš, Vojtěch Viktorin et al.
2 citations
preprint
In healthy volunteers, two doses of psilocybin (0.26 mg/kg) given at least 56 days apart produced moderate acute psychedelic effects that were mostly pleasant or fluctuating, with only one unpleasant experience. All sessions ended in a positive or neutral state. Psilocybin led to sustained positive effects across all domains of the Persisting Effects Questionnaire, with negligible negative effects. Contrary to expectations, dread of ego dissolution was not linked to negative long-term outcomes. Peak experiences culminating in positive mood were associated with positive lasting effects, while the type of experience (pleasant or mixed) did not correlate with the intensity or direction of the lasting effect. Results were independent of previous psychedelic experience, sex, or study setting.
Journal of Psychopharmacology
January 1, 2026
Petr Scholle, Štěpán Wenke, Tereza Nekovářová et al.
1 citation
Under psilocybin, healthy volunteers perceived time as moving more slowly and their temporal precision decreased, particularly for intervals longer than 2 seconds. In a double-blinded placebo-controlled study with 24 participants, the bisection point shifted rightward, indicating subjective time slowing, and the just noticeable difference increased, reflecting reduced accuracy. These changes were captured both by performance on the Temporal Bisection Task and by self-report scales. The findings suggest psilocybin disrupts cognitive functions such as working memory and attention, altering time perception through serotonergic system involvement.
The International Journal of Neuropsychopharmacology
February 1, 2025
Martin Kuchař, Klara Gotwaldova, Jan Borovička et al.
1 citation
Tryptamine concentrations in psychotropic mushrooms vary enormously, which may alter medicinal effects compared to chemically pure psilocybin. Storage conditions strongly affect alkaloid decay: the greatest degradation occurred in fresh mushrooms stored at −80°C, while the least decay was seen in dried biomass kept in the dark at room temperature. The study measured psilocybin, psilocin, baeocystin, norbaeocystin, and aeruginascin in a large sample set of mushroom genera, using freshly cultivated Psilocybe cubensis fruit bodies for stability monitoring, and analyzed mycelium and individual fruiting body parts with validated UHPLC-MS/MS.