Development of the Japanese version of the Ego‐Dissolution Inventory (EDI)

A Japanese version of the Ego-Dissolution Inventory (EDI) was developed through a translation and back-translation process following international guidelines. Two Japanese psychiatrists independently translated the original English EDI, reconciled differences, and had the resulting version back-translated into English. The original authors reviewed and approved the back-translated version after iterative revisions. The final Japanese EDI is intended to help assess ego-dissolution experiences during psychedelic-assisted therapy in Japanese-speaking populations. Further research is needed to test the reliability and validity of this new instrument.

Study at a glance

Abstract

Abstract Aim Psychedelics have recently gained attention as potential therapeutic agents for various psychiatric disorders. Previous research has highlighted that a diminished sense of self, commonly termed “ego‐dissolution” is a pivotal feature of the psychedelic‐induced state. While the Ego‐Dissolution Inventory (EDI) is a widely acknowledged instrument for measuring this phenomenon, no Japanese version has been available. This study aimed to develop a Japanese version of the EDI. Methods We adhered to the “Guidelines for Best Practices in the Translation and Cultural Modification Process for Patient‐Reported Outcomes Instruments: Document from the ISPOR Committee on Translation and Cultural Modification” during our translation approach. Two Japanese psychiatrists independently conducted initial translations, and a consolidated version was achieved via mutual agreement. This version was then back‐translated to English and assessed by the original authors for consistency. The repetitive modification process was conducted in continuous dialogues with the original authors until they accepted the concluding back‐translated version. Results The finalized, approved back‐translated version of the EDI is presented in the accompanying figure. In addition, the authorized Japanese version of the EDI is included in the Appendix. Conclusions In this study, we successfully developed the Japanese version of the EDI. This instrument will assist in assessing ego‐dissolution experiences associated with psychedelic‐assisted therapy among Japanese speakers. Additional studies are necessary to evaluate the reliability and validity of this newly translated instrument.