The revival of the psychedelic experience scale: Revealing its extended-mystical, visual, and distressing experiential spectrum with LSD and psilocybin studies

Summary & key facts

Researchers looked at whether a common psychedelic questionnaire called the Psychedelic Experience Scale (PES) measures more than just "mystical" experiences. They used about 240 questionnaire responses from 140 healthy people who took moderate to high doses of LSD or psilocybin in six studies. The team used careful item selection and statistical grouping to show that the PES can be split into more meaningful parts, including visual experiences and distressing experiences, which makes the scale cover psychedelic experiences more fully than before.

Key facts:

• The study used about 240 PES measurements from 140 healthy people across six studies with moderate to high doses of LSD or psilocybin.
• The researchers tested whether the PES includes reliable parts beyond the well-known 30-question mystical scale (MEQ30).
• They removed very rare items, picked candidate questions, and used statistical methods that find and confirm groups of related questions.
• The original four parts of the MEQ30 were confirmed to be reliable in this data set.
• Four additional reliable subscales were found for non-mystical items: paradoxicality (strange or puzzling experiences), connectedness (feeling linked to people or the world), visual experience, and distressing experience.
• Paradoxicality and connectedness were strongly linked to the MEQ30 mystical subscale, meaning they relate closely to what people call mystical experiences.
• Adding the new subscales improved how well the PES matched a different broad altered-states questionnaire, so the PES now explains more of the variety in psychedelic reports.
• The authors propose a new MEQ40 (the original 30 mystical items plus paradoxicality and connectedness) and a PES48 that together describe psychedelic experience more completely; the full PES100 is offered for future research.
• The results come from healthy volunteer studies in controlled settings and excluded very rare experiences, so the findings may need testing in other groups and real-world contexts before we assume they apply everywhere.

Abstract

BACKGROUND: Research with the Psychedelic Experience Questionnaire/Scale (PES) focuses on questions relating to mystical experience (Mystical Experience Questionnaire (MEQ)). The psychometric potential of the non-MEQ items of the PES remains largely unexplored. AIMS: We investigated whether the PES also yields subscales besides the MEQ30 subscales. METHODS: Data from 239 PES measurements (140 healthy participants) from six studies with moderate to high doses of lysergic acid diethylamide and/or psilocybin were included. New subscales (with items other than MEQ30) were created and validated as follows: (1) theoretical derivation of candidate items; (2) removal of items with rare experiences; (3) exploratory factor analysis; and (4) confirmatory factor analysis. Correlations of subscales within the PES and between the PES and the 5-Dimensional Altered States of Consciousness Scale (5D-ASC) were performed. In addition, a cluster analysis using all items (except rare experiences) was performed. RESULTS: The reliability of the four original factors of the MEQ30 was confirmed and four additional factors for the non-MEQ items were revealed: paradoxicality, connectedness, visual experience, and distressing experience. The first two additional factors were strongly correlated with the MEQ30 mystical subscale. Adding the new subscales to the MEQ30 subscales increased the explained variance with the 5D-ASC. The cluster analysis confirmed our main results and provided additional insights for future psychedelic psychometrics. CONCLUSION: The study yields a new validated 6-factor structure for extended mystical experience (MEQ40: MEQ30 + Paradoxicality + Connectedness) and covers psychedelic experience as a whole more comprehensively than has hitherto been possible within a single questionnaire (PES48). The entire PES (PES100) can also be used for further future psychedelic-psychometric research.

Topics

Forensic Toxicology and Drug Analysis Paranormal Experiences and Beliefs Psychedelics and Drug Studies

Categories

Clinical Psychology Psychology Social Sciences

Tags

Anxiety Clinical psychology Confirmatory factor analysis Experiential avoidance Exploratory factor analysis Hallucinogen Mathematics Mysticism Philosophy Psilocybin Psychiatry Psychology Psychometrics Statistics Structural equation modeling Theology

Substances

LSD Psilocybin

Conditions & symptoms

Anxiety