International journal of methods in psychiatric research
June 1, 2026
Kurt Stocker, Matthias Hartmann, Frederick S Barrett et al.
The eight-factor structure of the Psychedelic Experience Scale (PES48), which includes the Mystical Experience Questionnaire (MEQ30) and additional factors for paradoxicality, connectedness, visual experience, and distressing experience, is valid for use in English. Analysis of 280 measurements from 145 healthy participants in four placebo-controlled psilocybin studies found that six subscales have high internal consistency, one good, and one acceptable. Both the MEQ30 and MEQ40 models show acceptable to good model fits, with better fits in English than in German. All six MEQ40 scale means were higher in English data, suggesting that the PES48 provides a broader conceptualization of mystical and non-mystical psychedelic experiences, and that setting may influence mystical experience.
Repository for Publications and Research Data (ETH Zurich)
April 30, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
The Psychedelic Experience Scale (PES48) has an eight-factor structure that includes the well-validated Mystical Experience Questionnaire (MEQ30) plus four additional factors: paradoxicality, connectedness, visual experience, and distressing experience. This study tested whether the full eight-factor structure is valid in English, using data from 280 PES measurements from 145 healthy participants in four placebo-controlled psilocybin studies. Six of the eight subscales showed high internal consistency, one good, and one acceptable. Confirmatory factor analysis indicated acceptable to good model fits for the MEQ30 and MEQ40, with English data showing better fits than the German validation sample. The findings suggest the PES48 is a valid psychometric tool in English, enabling broader measurement of mystical and non-mystical aspects of psychedelic experience.
Religion Brain & Behavior
March 31, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
After administration of LSD, psilocybin, mescaline, or DMT, mystical oneness—the core of mystical experience—showed dose-sensitive strong correlations with luminous light and renewal, and a moderate-to-strong correlation with ego disintegration. These findings from 386 healthy participants across 15 studies support a broader, dynamic model of mystical experience, where mystical oneness unfolds with ego disintegration, renewal, and luminous light. The results offer insights for psychedelic-assisted therapy.
Repository for Publications and Research Data (ETH Zurich)
January 1, 2026
Kurt Stocker, Matthias Hartmann, Frederick S. Barrett et al.
Mystical oneness after psychedelics is linked to ego disintegration, renewal, and luminous light, and these connections intensify with higher doses. Analyzing 816 measurements from 386 healthy participants given LSD, psilocybin, mescaline, or DMT across 15 studies, researchers found dose-sensitive strong correlations between mystical oneness and luminous light and renewal, and a moderate-to-strong correlation with ego disintegration. The results support a dynamic model of mystical experience and suggest relevance for psychedelic-assisted therapy.
Repository for Publications and Research Data
January 1, 2025
Kurt Stocker, Matthias Hartmann, Schmid, Yasmin et al.
The Altered States of Consciousness Scale (ASC), commonly used in psychedelic research, has two incompatible scoring systems: a three-dimensional model (3D-ASC) and an eleven-subscale model (11-ASC). Analyzing data from 901 questionnaires across 16 psychedelic studies, researchers found that ten of the eleven subscales could be reorganized into three higher-order dimensions—Positive, Distressing, and Perceptual effects—that closely mirror the original three dimensions but with improved statistical fit. This revised version, called the 3D-ASCr, retains the Anxiety subscale separately due to floor effects. The 3D-ASCr is recommended for use with classic serotonergic psychedelics in clinical practice and research.