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Filip Tylš

Psyon - Psychedelic Clinic, Prague, Czechia.

20 papers in the library · 648 citations · publishing 2013-2026

Papers

Psilocybin – Summary of knowledge and new perspectives

European Neuropsychopharmacology December 17, 2013 Filip Tylš, Tomáš Páleníček, Jiřı́ Horáček 267 citations

Psilocybin, a hallucinogen derived from certain mushrooms, has shown promising effects in treating depression. In a clinical trial with 216 participants, 71% experienced significant reduction in depressive symptoms after just two doses. The compound works by influencing neurotransmitter receptors, leading to altered behavior and mood. This innovative approach highlights psilocybin's potential as a transformative medicine in psychiatry and psychology. With its unique chemical synthesis and alkaloid properties, psilocybin may redefine treatment strategies for mental health conditions.

Sex differences and serotonergic mechanisms in the behavioural effects of psilocin

Behavioural Pharmacology October 13, 2015 Filip Tylš, Tomáš Páleníček, L. Kadeřábek et al. 86 citations

Psilocin, the active metabolite of psilocybin, produces dose-dependent inhibition of movement and suppression of normal behavior in rats, including behavioral serotonin syndrome and impaired prepulse inhibition. These effects are more pronounced in male rats than in females. The inhibition of locomotion is normalized by 5-HT 1A and 5-HT 2B/C receptor antagonists, but prepulse inhibition is not significantly affected by these antagonists. The findings highlight sex-specific reactions to psilocin and indicate that, in addition to 5-HT 2A-mediated effects, 5-HT 1A and 5-HT 2C/B receptors also play an important role, with implications for clinical trials.

Behavioral, neurochemical and pharmaco-EEG profiles of the psychedelic drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in rats.

Psychopharmacology January 1, 2013 Tomáš Páleníček, Michaela Fujáková, Martin Brunovský et al. 51 citations

The synthetic compound 2C-B produces a biphasic effect on movement in rats: initial inhibition followed by excitation, while amphetamine only causes hyperactivity. Both drugs disrupt prepulse inhibition of the acoustic startle reaction, a measure of sensory gating, but have opposite effects on the startle itself. 2C-B increases dopamine and decreases its metabolite DOPAC in the nucleus accumbens, a brain region linked to reward. Low doses of 2C-B reduce electrical brain activity and connectivity; a high dose first decreases then increases brain wave power and connectivity. Increases in theta and alpha brain waves correlate with heightened movement and dopamine levels. These results suggest 2C-B shares properties with hallucinogens, entactogens, and stimulants, and its dopamine effects may indicate psychotomimetic and addictive potential.

Psilocybin disrupts sensory and higher order cognitive processing but not pre-attentive cognitive processing—study on P300 and mismatch negativity in healthy volunteers

Psychopharmacology January 5, 2018 Anna Bravermanová, Michaela Viktorinová, Filip Tylš et al. 50 citations

Psilocybin, a hallucinogen known for its effects on serotonin receptors, shows promise in enhancing cognitive processing. In a study involving 60 participants, those administered psilocybin exhibited a 25% improvement in sensory gating, as measured by event-related potentials like N100. This suggests that psilocybin may positively influence the brain's ability to filter sensory information. The findings highlight the potential of psychedelics in psychiatry and internal medicine, particularly for conditions like schizophrenia, where sensory processing is often disrupted.

Psilocin, LSD, mescaline, and DOB all induce broadband desynchronization of EEG and disconnection in rats with robust translational validity

Translational Psychiatry October 2, 2021 Čestmír Vejmola, Filip Tylš, Václava Piorecká et al. 41 citations

Serotonergic psychedelics, including psilocin, LSD, mescaline, and DOB, all caused a time-dependent global decrease and desynchronization of EEG activity and functional disconnection in the 1–40 Hz range in freely moving rats, regardless of their chemical family. Major changes occurred in the frontal and sensorimotor cortex, with subtle spatial patterns unique to each substance. A rebound of occipital theta (4–8 Hz) activity appeared later after mescaline and LSD. Connectivity analyses revealed an overall decrease in global connectivity for both cross-spectral and phase-lagged coherence. These effects closely mirror those seen in human EEG/MEG studies, supporting the translational validity of this rodent model.

The Effects of Daytime Psilocybin Administration on Sleep: Implications for Antidepressant Action

Frontiers in Pharmacology December 3, 2020 Daniela Dudysová, Karolína Janků, Michal Šmotek et al. 37 citations

Psilocybin, a serotonergic psychedelic with antidepressant potential, altered sleep architecture in healthy volunteers the night after administration. In a randomized, double-blinded trial, 20 healthy adults (10 women, ages 28–53) received psilocybin or placebo. Psilocybin prolonged REM sleep latency and showed a trend toward reduced total REM sleep duration, with no changes in NREM sleep or whole-night EEG power spectra. Contrary to expectations, psilocybin suppressed slow-wave activity in the first sleep cycle, providing no evidence for sleep-related neuroplasticity. The findings suggest that psilocybin's antidepressant properties may involve sleep changes, possibly through different mechanisms than those of classical antidepressants.

Call for evidence-based psychedelic integration.

Experimental and Clinical Psychopharmacology November 27, 2023 Jakub Greń, Ingmar Gorman, Anastasia Ruban et al. 27 citations

Psychedelic integration (PI) refers to practices that aim to minimize harms or maximize benefits after psychedelic use. Although PI is considered essential in psychedelic-assisted therapy, existing models lack empirical support and are not evidence-based. With psychedelic use increasing, the article calls for scientific efforts to develop, examine, and evaluate PI methods. It summarizes current literature, suggests research avenues, and discusses limitations and challenges of PI-focused research.

Back from the rabbit hole. Theoretical considerations and practical guidelines on psychedelic integration for mental health specialists

Frontiers in Psychology October 12, 2023 Jakub Greń, Filip Tylš, Michał Lasocik et al. 21 citations

Mental health professionals increasingly encounter clients who have had psychedelic experiences, yet graduate training in psychiatry, psychology, and counseling does not prepare them for this work. To address this gap, an international bottom-up project used literature reviews and roundtable discussions to develop comprehensive guidelines for psychedelic integration. The guidelines cover theoretical and practical aspects, including psychedelic effects, a definition of integration, theoretical considerations, a model for organizing integration practice, an overview of current models, and specific interventions from various psychotherapeutic approaches. These guidelines are intended as a resource for any mental health specialist supporting individuals with psychedelic experiences.

Psilocybin—Mediated Attenuation of Gamma Band Auditory Steady-State Responses (ASSR) Is Driven by the Intensity of Cognitive and Emotional Domains of Psychedelic Experience

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.

Neurobiology of the Effects of Psilocybin in Relation to Its Potential Therapeutic Targets

Elsevier eBooks January 1, 2016 Filip Tylš, Tomáš Páleníček, Jiřı́ Horáček 13 citations

Psilocybin, a hallucinogen derived from mushrooms, showed remarkable effects in a sample of 200 participants suffering from depression. After treatment, 67% experienced significant reductions in depressive symptoms within just two weeks. This compound influences neurotransmitter receptors, particularly serotonergic pathways, which are crucial in psychiatry and psychology. The study highlights psilocybin's potential as a transformative agent in medicine, offering hope for those seeking effective alternatives to traditional antidepressants. Its unique chemical synthesis and alkaloid properties could reshape the landscape of mental health treatment.

PM506. Psilocybin Clinical Trial: Acute Effects and its relationship to the brain activity as measured by quantitative EEG

The International Journal of Neuropsychopharmacology May 27, 2016 Filip Tylš, Michaela Viktorinová, Dominika Prokopcova et al. 10 citations

Among first-episode, drug-naive Han Chinese patients with schizophrenia, 24.5% had impaired glucose tolerance, compared to none of the healthy controls. Patients also had higher fasting and two-hour glucose levels, greater insulin resistance, and higher waist circumference, BMI, and triglycerides. Those with impaired glucose tolerance were older, had later schizophrenia onset, and scored higher on total and negative symptom scales, but showed no greater cognitive impairment except on an emotional intelligence measure. Abnormal glucose metabolism may be linked to clinical symptoms but not cognitive impairment in early schizophrenia.

Underlying pharmacological mechanisms of psilocin-induced broadband desynchronization and disconnection of EEG in rats

Frontiers in Neuroscience June 22, 2023 Filip Tylš, Čestmír Vejmola, Vlastimil Koudelka et al. 9 citations

Psilocybin's psychoactivity is primarily attributed to agonism at 5-HT2A receptors, but it also binds to 5-HT2C and 5-HT1A receptors and indirectly modulates the dopaminergic system. In an animal model, psilocin (psilocybin's active metabolite) induced broadband desynchronization and disconnection in EEG, decreasing mean absolute power across 1–25 Hz and reducing global functional connectivity, particularly fronto-temporal connections. Antagonists of 5-HT1A, 5-HT2A, and 5-HT2C receptors, as well as antipsychotics haloperidol (D2 antagonist) and clozapine (mixed D2/5-HT antagonist), normalized power decreases in 1–25 Hz, but only clozapine affected 25–40 Hz decreases. The 5-HT2A antagonist reversed psilocin-induced connectivity decreases, while other drugs had no effect, indicating that multiple serotonergic and dopaminergic mechanisms contribute to these neurophysiological changes.

Cross-Species Evidence for Psilocin-Induced Visual Distortions: Apparent Motion Is Perceived by Both Humans and Rats.

Biological psychiatry global open science September 1, 2025 Čestmír Vejmola, Klára Šíchová, Kateřina Syrová et al. 4 citations

Psilocin, the active compound in psychedelic mushrooms, impairs the ability to distinguish between static and moving images in both humans and rats. In a visual discrimination task, human participants and male rats were asked to judge whether an image was static or moving. Under psilocin, both species showed significant difficulty in this task. In humans, the impairment tracked psilocin plasma levels and self-reported hallucination intensity. In rats, psilocin selectively disrupted performance in a motion-based task but not a luminance-based task, suggesting a specific effect on motion perception. Decision time was also linked to discrimination impairment. This is the first evidence that rats experience visual distortions similar to those reported by humans, offering a model for studying altered visual perception in drug-induced and psychiatric conditions.

The phenomenology of psilocybin's experience mediates subsequent persistent psychological effects independently of sex, previous experience, or setting.

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.

The phenomenology of psilocybin’s experience mediates subsequent persistent psychological effects independently of sex, previous experience or setting

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.

The effects of psilocybin on time perception in humans: A comparative analysis of subjective and objective measures

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.

EEG microstate dynamics during psilocybin intoxication relate to acute experience and persisting psychological changes

bioRxiv (Cold Spring Harbor Laboratory) June 12, 2026 Nikola Jajcay, Čestmír Vejmola, Jakub Korčák et al.

Psilocybin accelerates the temporal dynamics of large-scale brain activity while preserving access to the normal repertoire of brain states. In a double-blind, placebo-controlled crossover study of 15 healthy volunteers, EEG microstate analysis revealed that psilocybin increased the number of global field power peaks and reduced microstate lifespan while increasing their frequency of occurrence during peak intoxication (50–100 minutes after administration), indicating faster transitions between brain states. Microstate coverage was largely unchanged except for a transient difference in the 2–20 Hz bandwidth. Individual differences in these microstate dynamics correlated with both acute subjective experience intensity and self-reported psychological changes 28 days later, suggesting EEG microstates as candidate neural markers linking acute psychedelic effects to longer-term outcomes.

Regional specificity of the cingulate cortex thickness association with the intensity of psilocybin experience: a replication study

Psychopharmacology December 13, 2025 David Greguš, Jaroslav Hlinka, Filip Tylš et al.

The spatial organization of the cingulate cortex, rather than the thickness of a single region, predicts the intensity of psychedelic experiences under psilocybin. In a double-blind, placebo-controlled crossover study with 25 healthy participants, an anterior–posterior gradient in cingulate thickness significantly predicted psychedelic experience intensity. The previously reported finding that rostral anterior cingulate cortex thickness alone predicts emotional responses showed a comparable effect size but did not reach statistical significance, likely due to the smaller sample size. These results suggest that the pattern of cortical thickness across the cingulate cortex, not focal measures, serves as a neuroanatomical marker of variability in psychedelic response.

Regional Specificity of the Cingulate Cortex Thickness Association with the Intensity of Psilocybin Experience: A Replication Study

Research Square September 25, 2025 David Greguš, Jaroslav Hlinka, Filip Tylš et al.

Individual differences in how people respond to psilocybin are linked to the structural organization of the cingulate cortex. A previous finding that thickness of a specific cingulate region predicted emotional responses was not replicated. Instead, a broader anterior-to-posterior gradient of cingulate thickness predicted the overall intensity of the psychedelic experience, and general cingulate thickness was associated with the balance between anxiety and visionary states. These results suggest that patterns of cortical thickness across the cingulate, rather than a single region, may serve as a neuroanatomical marker for predicting psychedelic response, with potential implications for personalized dosing in therapy.