medRxiv
September 11, 2024
M. Nikolič, Pedro A. M. Mediano, Tom Froese et al.
6 citations
preprint
Psilocybin, a classic psychedelic, alters perception, cognition, and emotion by activating 5-HT2A receptors and reducing serotonin reuptake. In a placebo-controlled crossover study with 20 healthy individuals, electroencephalography tracked brain activity changes over 24 hours after oral psilocybin (0.26 mg/kg). Acutely, absolute power decreased in alpha and beta bands but increased in delta and gamma frequencies; alpha power decreased occipitally between 1 and 3 hours, and beta decreased frontally at 3 hours. Global functional connectivity in the alpha band dropped acutely, while Lempel-Ziv complexity increased at 1 and 1.5 hours.
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.
Addiction Biology
March 1, 2026
Isis Koutrouli, Vojtěch Brejtr, Marek Schwendt et al.
Psilocybin and ibogaine, given in a dose-escalation protocol, facilitated extinction learning in male rats that had self-administered cocaine. Psilocybin reduced active lever pressing one day after the second dose, with a nonsignificant reduction after the first dose; ibogaine significantly reduced pressing even after the first administration. Neither drug significantly altered cue-induced reinstatement of drug-seeking, though psilocybin showed a trend toward attenuation. The treatments had no side effects on general locomotor activity or anxiety-like behavior in the open field test. These results suggest psilocybin and ibogaine may support extinction learning and possibly protect against relapse, warranting further research into their antiaddictive potential.
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.
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.