Phenomenological assessment of psychedelics induced experiences: Translation and validation of the German Challenging Experience Questionnaire (CEQ) and Ego-Dissolution Inventory (EDI)
Katharina Dworatzyk, Tallulah Jansen, Timo Torsten Schmidt
PLoS One March 16, 2022 DOI: 10.1371/journal.pone.0264927 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Validation study Peer reviewed |
|---|---|
| Population | Participants in an online survey on psychedelics induced experiences |
| Topics | Altered states of consciousness Ego dissolution |
| Keywords | Psychedelic research Psychedelic science Psychedelic studies Psychedelic measurement Psychedelic validation Ego loss Ego dissolution measurement Ego dissolution assessment Psychometric validation Tool validation Instrument validation Questionnaire validation Measurement validation Scale validation Reliability study Consciousness research States of consciousness |
| Citations | 19 |
| Key points | The German translation of the Challenging Experience Questionnaire showed acceptable psychometric properties, while the German Ego-Dissolution Inventory required a revised 5-item factor structure to measure ego-dissolution. |
Abstract
Several measures have been designed to assess subjective experiences induced by psychedelic substances or other mind-altering drugs as well as non-pharmacological methods. Recently, two self-report questionnaires have been introduced to measure acute adverse effects following psilocybin ingestion and the phenomenon of ego-dissolution associated with the use of psychedelics, respectively. The 26-item Challenging Experience Questionnaire assesses multiple facets of psilocybin induced experiences on seven subscales, whereas the 8-item Ego-Dissolution Inventory consists of a unidimensional scale. In the present study, these questionnaires were translated into German and their psychometric properties then evaluated in an online survey on psychedelics induced experiences. Confirmatory factor analysis suggested an acceptable fit of the 7-factor structure of the German Challenging Experience Questionnaire with overall good internal consistency for all subscales. The factor structure did not differ based on gender or prior struggle with a psychiatric disorder, furthering the evidence of internal validity. Correlations with the State-Trait-Anxiety Inventory and the Altered States of Consciousness Rating Scale demonstrated convergent validity. Confirmatory factor analysis did not support the hypothesized single-factor structure of the German Ego-Dissolution Inventory and exploratory factor analysis suggested an alternative factor structure, where only five items loaded onto a common factor that was interpreted as ego-dissolution. Internal consistency of this 5-item measure was high and correlation with selected items of the Mystical Experience Questionnaire and Altered States of Consciousness Rating Scale supported convergent validity. Translation and validation of these questionnaires contribute to the advancement of common standards in the psychological and neuroscientific study of altered states of consciousness.