Integrating the Mystical Experience Questionnaire Into a Broader Psychometric Framework: English Validation of the Psychedelic Experience Scale and Comparison of Psilocybin and LSD Sessions Across Two Controlled Settings.
Kurt Stocker, Matthias Hartmann, Frederick S Barrett, William A Richards, Nathan D Sepeda, Laura Ley, Anna M Becker, Friederike Holze, Matthias E Liechti
International journal of methods in psychiatric research June 1, 2026 Peer reviewed DOI: 10.1002/mpr.70073 via PubMed
Summary
The eight-factor structure of the Psychedelic Experience Scale (PES48) has been validated for English, based on data from 280 measurements involving 145 healthy participants. Six of the eight subscales demonstrated high internal consistency, while two showed lower levels. The findings indicate that the PES48 is a valid psychometric tool for measuring both mystical and non-mystical experiences in psychedelic contexts, with higher scores observed in English participants compared to their German counterparts.
Study at a glance
| Design | observational cohort |
|---|---|
| Sample size | 145 |
| Population | healthy participants who experienced psilocybin in placebo-controlled studies |
| Key finding | The eight-factor PES48 is a valid psychometric tool in English for measuring mystical and non-mystical experiences. |
Abstract
For English, the validated part of Psychedelic Experience Scale (PES48) is a four-factor structure called the Mystical Experience Questionnaire (MEQ30). The other validated part of the PES48 consists of four more factors: two more mystical factors (paradoxicality and connectedness, which together with the MEQ30 form the MEQ40), and two more non-mystical factors (visual experience and distressing experience). However, this latter four-factor part of the PES48 has thus far only been validated for the German version of the PES48. We investigated whether the overall eight-factor structure of the PES48 (which includes the MEQ30 four-factor structure) can also be validated, and thus potentially be put to good use in English. Data from 280 English PES measurements (145 different healthy participants) from four placebo-controlled studies with low to high doses of psilocybin were included. The reliability of the eight subscales was evaluated using measures of internal consistency. The validity of the factor structure was assessed through model fit indices from confirmatory factor analysis. English results were then also compared with the German PES validation data set from Stocker et al. (2024). Six of the eight subscales (mystical, positive mood, transcendence of time and space, ineffability, connectedness, distressing experience) of the English PES48 show high internal consistency, one subscale (paradoxicality) shows good, and one (visual experience) acceptable internal consistency. Both MEQ models (MEQ30 and MEQ40) show similar fits (acceptable to good model fits). In English, both MEQ models show better fits than in German. All six MEQ40 scale means of the English data are higher compared to German data. The findings suggest that the eight-factor PES48 is also a valid psychometric tool in English. With the MEQ40 part of the PES48, one can measure mystical experience with a still wider conceptual breath than with the MEQ30. Furthermore, one can also measure non-mystical visual and distressing states in an overall more comprehensive and broader conceptualization of the psychedelic experience. Higher MEQ40 scale means for the English than the German study participants could inspire future research into the role of setting in relation to mystical experience.