Neuroimaging & Brain Measures

Language as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs

This review (2022) explores how the acute effects of psychedelic drugs impact speech organization regardless of its semantic content, and how to characterize the subjective effects of psychedelic drugs by analyzing the semantic content of written retrospective reports. It is suggested that researchers studying psychedelics can considerably expand the range of their potential scientific conclusions by analyzing brief interviews obtained before, during and after the acute effects.

Authors

  • Enzo Tagliazucchi

Published

Frontiers in Pharmacology
meta Study

Abstract

Psychedelics are drugs capable of eliciting profound alterations in the subjective experience of the users, sometimes with long-lasting consequences. Because of this, psychedelic research tends to focus on human subjects, given their capacity to construct detailed narratives about the contents of their consciousness experiences. In spite of its relevance, the interaction between serotonergic psychedelics and language production is comparatively understudied in the recent literature. This review is focused on two aspects of this interaction: how the acute effects of psychedelic drugs impact speech organization regardless of its semantic content, and how to characterize the subjective effects of psychedelic drugs by analyzing the semantic content of written retrospective reports. We show that the computational characterization of language production is capable of partially predicting the therapeutic outcome of individual experiences, relate to the effects elicited by psychedelics with those associated with other altered states of consciousness, drawing comparisons between the psychedelic state and the symptomatology of certain psychiatric disorders, and investigate the neurochemical profile and mechanism of action of different psychedelic drugs. We conclude that researchers studying psychedelics can considerably expand the range of their potential scientific conclusions by analyzing brief interviews obtained before, during and after the acute effects. Finally, we list a series of questions and open problems that should be addressed to further consolidate this approach.

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Research Summary of 'Language as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs'

Introduction

Psychedelic drugs, particularly serotonergic 5-HT2A receptor agonists, induce profound and idiosyncratic alterations in perception, sense of self, emotion and cognition that are difficult to capture using behavioural observation alone. Tagliazucchi notes that because users typically must rely on language to communicate the full extent of their subjective experiences, natural language reports are a potentially rich but underused source of data for understanding psychedelic phenomenology, mechanisms of action and therapeutic effects. The paper highlights a gap in recent literature: while questionnaires and neuroimaging have been widely applied, the interaction between psychedelics and language production — both in terms of the structure of speech during the acute state and the semantic content of retrospective reports — has received comparatively little systematic attention. This review sets out to synthesise work that uses computational natural language processing (NLP) to extract quantitative information from speech and text related to psychedelic experiences. Tagliazucchi describes two complementary aims: (1) to survey evidence on how acute psychedelic effects alter the organisation of speech independent of semantic content, and (2) to evaluate approaches that characterise the semantic content of retrospective reports and relate that content to pharmacology, neurobiology and therapeutic outcomes. The review also introduces fundamental NLP concepts and outlines open questions and methodological challenges for future research.

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