LSD and language: Decreased structural connectivity, increased semantic similarity, changed vocabulary in healthy individuals

This double-blind cross-over study (n=24) of a low/moderate dose of LSD (50μg) on the structure of language finds simpler and semantically more similar language after LSD.

Abstract

“Language has been explored as a window into the mind. Psychedelics, known to affect perception and cognition, seem to change language, but a systematic, time-dependent exploration is lacking. Therefore, we aimed at mapping the psychedelic effects on language over the time course of the acute and sub-acute effects in an explorative manner. For this, 24 healthy volunteers (age [mean±SD, range]: 35±11, 25–61 years; 33% women) received 50 μg lysergic acid diethylamide (LSD) or inactive placebo in a randomized, double-blind, placebo-controlled, crossover study. We assessed different language productions (experience reporting, storytelling), components (structure, semantics, vocabulary) and time points (+0 h to +24 h). Language productions included 5-min experience reporting (+1.5 h, +6.5 h) and 1-min storytelling (+0 h, +2 h, +4 h, +6 h, +24 h). Language structure was assessed by computing speech topology (SpeechGraphs), semantics by semantic distances (FastText), vocabulary by word categories (LIWC). LSD, compared to placebo, changed language structure, including decreased verbosity, lexicon, global and local connectivity (+1.5 h to +4 h); decreased semantic distances between neighbouring words and overall words (+2 h to +24 h); and changed vocabulary related to grammar, persons, time, space and biological processes (+1.5 h to +24 h). In conclusion, low to moderate LSD doses changed language over diverse production types, components and time points. While simpler and disconnected structure and semantic similarity might reflect cognitive impairments, changed vocabulary might reflect subjective perceptions. Therefore, language under LSD might provide a window into the psychedelic mind and automated language quantifications should be better explored as valuable tools to yield more unconstrained insights into psychedelic perception and cognition.”

Authors: Isabel Wießner, Marcelo Falchia, Dimitri Daldegan-Bueno, Fernanda Palhano-Fontes, Rodolfo Olivieri, Amanda Feilding, Draulio B. Araujo, Sidarta Ribeiro, Natália B. Mota & Luís F. Tófoli

Summary of LSD and Language

Language is a fundamental tool for human communication, enabling us to express thoughts and experiences and tell stories. Recent computational approaches provide powerful tools for automated language quantifications, such as structural analyses of speech connectedness and semantic analyses of dream content.

Serotonergic psychedelics alter perception, emotion and cognition, but are often measured by predefined items in self-report questionnaires. So, might psychedelic language provide a more direct window into the psychedelic mind?

Psychedelics increase semantic distances in free association and creativity tasks, and semantic similarities to positive sentiment. Online experience reports describe thinking distortions, emergencies and perceptual alterations.