Aims: The experience of a compromised sense of ‘self’, termed ego-dissolution, is a key feature of the psychedelic experience and acute psychosis. This study aimed to validate the Ego-Dissolution Inventory (EDI), a new 8-item self-report scale designed to measure ego-dissolution. Additionally, we aimed to investigate the specificity of the relationship between psychedelics and ego-dissolution. Method: Sixteen items relating to altered ego-consciousness were included in an internet questionnaire; 8 relating to the experience of ego-dissolution (comprising the EDI), and 8 relating to (...) the antithetical experience of increased self-assuredness. Items were rated using a visual analogue scale. Participants answered the questionnaire for experiences with classical psychedelic drugs, cocaine or alcohol. They also answered the 7 questions from the Mystical Experiences Questionnaire (MEQ) relating to the experience of unity with one’s surroundings. Results: 691 participants completed the questionnaire, providing data for 1828 drug experiences (1043 psychedelics. 377 cocaine. 408 alcohol). Exploratory factor analysis demonstrated that the 8 EDI items loaded exclusively onto a single common factor, which was orthogonal to a second factor comprised of the items relating to increased self-assuredness (rho= -.110), demonstrating discriminant validity. The EDI correlated strongly with our measure of unitive experience (rho =.735), demonstrating convergent validity. EDI internal consistency was excellent (Cronbach’s alpha 0.93). Three analyses confirmed the specificity of ego-dissolution for experiences occasioned by psychedelic drugs. Firstly, EDI score correlated with drug-dose for psychedelic drugs (rho=.371), but not for cocaine (rho=.115) or alcohol (rho=-0.055). Secondly, the linear regression line relating the subjective intensity of the experience to EDI was significantly steeper for psychedelics (unstandardized B coefficient= 0.701) compared with cocaine (0.135) or alcohol (0.144). Finally, a binary support vector machine classifier identified experiences occasioned by psychedelic drugs vs. cocaine or alcohol with over 85% accuracy using ratings of ego-dissolution and ego-inflation alone. Conclusions: Our results demonstrate the psychometric structure, internal consistency and construct validity of the EDI. Moreover, we demonstrate the close relationship between ego-dissolution and the psychedelic experience. The EDI will facilitate the study of the neuronal correlates of ego-dissolution, which is relevant for psychedelic-assisted psychotherapy and our understanding of psychosis. (shrink)

The ethical value—and to some scholars, necessity—of providing trial patients with post-trial access (PTA) to an investigational drug has been subject to significant attention in the field of research ethics. Although no consensus has emerged, it seems clear that, in some trial contexts, various factors make PTA particularly appropriate. We outline the atypical aspects of psychedelic clinical trials that support the case for introducing the provision of PTA within research in this field, including the broader legal status of psychedelics, the (...) nature of the researcher-therapist/participant relationship, and the extended time-frame of the full therapeutic process. As is increasingly understood, the efficacy of psychedelic-assisted psychotherapy is driven as much by extrapharmacological elements and the cultural therapeutic container as by the drug itself. As such, we also advocate for a refocusing of attention from post-trial access to a broader concept encompassing other elements of post-trial care. We provide an overview of some of the potential post-trial care provisions that may be appropriate in psychedelic clinical trials. Although the World Medical Association’s Declaration of Helsinki calls on researchers, sponsors, and governments to make provisions for post-trial access, such provision may feel impracticable or out-of-reach within psychedelic trials that are already constrained by a high resource demand and significant bureaucratic burden. We show how conceiving of post-trial provision as an integral site of the research process, and an appropriate destination for research funding, will serve to develop the infrastructure necessary for the post-legalisation psychedelic medicine ecosystem. (shrink)