Classification Schemes of ​Altered States of Consciousness

Abstract

In recent years, there has been a renewed interest in the conceptual and empirical study of altered states of consciousness (ASCs) induced pharmacologically or otherwise due to their potential for clinical application. To draw attention to the rich history of research in this domain, we review prominent classification schemes that have been proposed to introduce systematicity in the scientific study of ASCs. The reviewed ASC classification schemes fall into three groups according to the criteria they use for categorization: (1) based on the nature, variety, and intensity of subjective experiences (state-based), including conceptual descriptions and psychometric assessments, (2) based on the technique of induction (method-based), and (3) descriptions of neurophysiological mechanisms of ASCs (neuro/physio-based). Comparison and extension of existing classification schemes can inform attempts to identify neural correlates of consciousness especially when comparing mechanisms through which an ASC is induced and its ensuing subjective experience. Further, an overview of what defining ASC characteristics different authors have proposed can inform future research in the conceptualization and quantification of ASC features, including the identification of features that might be relevant in clinical research. This review concludes by clustering the concepts from the state-based schemes, which are suggested for classifying ASC experiences. The resulting clusters can inspire future approaches to formulate and quantify the core phenomenology of ASC experiences to assist in basic and clinical research.

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Speakers

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​Larry Fort is a PhD student at the University of Liège where he works in the Physiology of Cognition lab as part of the GIGA-Cyclotron Research Center (CRC). His background is in general psychology (B.S.) and Experimental Psychology (M.A.) where he took interests in altered states of consciousness (ASCs). His research aims to understand phenomenological, neurobiological, and physiological underpinnings of ASCs, both phenomenological and non-phenomenological, to elucidate their interconnectedness and ultimately suggest how to create ASCs that elicit specific types of experience for possible clinical benefit