Skip to content

Andres Ort

Department of Adult Psychiatry and Psychotherapy, Psychiatric University Clinic Zurich and University of Zurich, Lenggstrasse 31, Zurich 8032, Switzerland.

4 papers in the library · 91 citations · publishing 2023-2026

Papers

TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology.

iScience May 19, 2023 Andres Ort, John W Smallridge, Simone Sarasso et al. 47 citations

Classical psychedelic drugs like psilocybin induce profound changes in consciousness, including heightened sensory-emotional awareness and arousal, accompanied by increased spontaneous EEG signal diversity. By combining Transcranial Magnetic Stimulation (TMS) with EEG, this work shows that psilocybin creates a state of increased chaotic brain activity, which is not due to altered complexity in causal interactions between brain regions. The study also maps regional effects of psilocybin on TMS-evoked activity, identifying changes in frontal brain structures that may relate to the phenomenology of psychedelic experiences.

Psilocybin-assisted therapy for relapse prevention in alcohol use disorder: a phase 2 randomized clinical trial

EClinicalMedicine March 14, 2025 Raoul Bitar, Simon Halm, Christina Rossgoderer et al. 42 citations

A randomized controlled trial investigated whether psilocybin-assisted therapy could reduce relapse in patients with alcohol use disorder. The study compared psilocybin therapy against a control condition, finding that the psilocybin group showed a significantly lower rate of heavy drinking days over the follow-up period. The results suggest that psilocybin, when combined with psychotherapy, may be a promising intervention for relapse prevention in alcohol dependence, though further research is needed to confirm these findings.

Psilocybin-induced alterations in EEG power, connectivity and network dynamics in healthy subjects: Correlations with subjective experience and implications for therapeutic applications

Progress in Neuro-Psychopharmacology and Biological Psychiatry January 1, 2026 Cheng-Teng Ip, Sebastian Olbrich, Mateo de Bardeci et al. 1 citation

In a double-blind, randomized, crossover, placebo-controlled trial with 25 healthy adults, psilocybin (10–20 mg oral) decreased EEG power in slow frequency bands (theta and alpha) and increased power in fast frequency bands (beta, gamma1, gamma2) compared to placebo. Connectivity within the default-mode network and localized parietal network increased under psilocybin. Changes in EEG power and connectivity correlated positively with subjective experiences measured by the Altered States of Consciousness Questionnaire. Baseline EEG features predicted subjective alterations, suggesting that specific brain activity patterns could serve as biomarkers for tailoring psilocybin therapy.

The influence of psilocybin on subconscious and conscious emotional learning

iScience May 19, 2024 Andres Ort, John W Smallridge, Erich Seifritz et al. 1 citation

Psilocybin, a serotonergic psychedelic being studied for psychiatric treatment, preserved reinforcement learning in a probabilistic cue-reward task using emotional faces presented consciously or subconsciously. Across dosages, psilocybin was statistically noninferior to placebo and suggested higher exploratory behavior. The 20 mg group showed significantly better learning rates than placebo. Psilocybin led to inferior learning with subconscious cues compared to placebo, but better results with conscious neutral cues in some conditions. The findings indicate that modulating serotonin signaling with psilocybin sufficiently preserves reinforcement learning.