LSD and language: Decreased structural connectivity, increased semantic similarity, changed vocabulary in healthy individuals.
Isabel Wießner, Marcelo Falchi, Dimitri Daldegan-Bueno, Fernanda Palhano-Fontes, Rodolfo Olivieri, Amanda Feilding, Draulio B Araujo, Sidarta Ribeiro, Natália Bezerra Mota, Luís Fernando Tófoli
European Neuropsychopharmacology March 1, 2023 DOI: 10.1016/j.euroneuro.2022.12.013 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized, double-blind, placebo-controlled, crossover study Peer reviewed |
|---|---|
| Sample size | 24 |
| Population | Healthy volunteers |
| Intervention | Lysergic acid diethylamide (LSD) |
| Dose | 50 μg |
| Duration | 24 hours |
| Topics | LSD |
| Keywords | Cognition Natural language processing Semantics Vocabulary Psychedelics hallucinogens Psychoactive drugs Language processing linguistics Speech patterns |
| Citations | 6 |
| Key points | LSD, compared to placebo, changed language structure, decreased semantic distances between words, and altered vocabulary across multiple time points and production types. |
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.
Comparable studies
Other randomized controlled trials on LSD, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases Patients with anxiety associated with life-threatening diseases | 2014 | Randomized controlled trial | n = 12 |
| Dose-Response Study of N,N-Dimethyltryptamine in Humans Experienced hallucinogen users | 1994 | Double-blind, saline placebo-controlled, randomized study | n = 12 |
| Acute Effects of Lysergic Acid Diethylamide in Healthy Subjects Healthy subjects (8 women, 8 men) | 2014 | Double-blind, randomized, placebo-controlled, crossover study | n = 16 |
| Changes in global and thalamic brain connectivity in LSD-induced altered states of consciousness are attributable to the 5-HT2A receptor Healthy human participants | 2018 | Double-blind, randomized, counterbalanced, cross-over study | n = 24 |
| LSD-induced entropic brain activity predicts subsequent personality change. Healthy adults | 2016 | Balanced-order, placebo-controlled study | n = 19 |
Citations in the library
Cited by 5
- Hemispheric annealing and lateralization under psychedelics (HEALS): A novel hypothesis of psychedelic action in the brain. Journal of Psychopharmacology May 1, 2025
- Quantitative natural language processing markers of psychoactive drug effects: A pre-registered systematic review Journal of Psychopharmacology February 16, 2025
- Participant Experiences of Therapeutic Touch in Psilocybin-Assisted Therapy. Brain and Behavior February 1, 2026
- Mixed-methods analysis on psychedelic-augmented meditation experiences from a randomized controlled mindfulness retreat Scientific Reports March 18, 2026
- Cellular mechanisms of serotonergic psychedelics - apical hypercontextualisation. Neuroscience & Biobehavioral Reviews July 1, 2026
Cites 23
- Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology July 1, 2008
- The Pharmacology of Lysergic Acid Diethylamide: A Review CNS Neuroscience & Therapeutics November 11, 2008
- Using Psilocybin to Investigate the Relationship between Attention, Working Memory, and the Serotonin 1A and 2A Receptors Journal of Cognitive Neuroscience October 1, 2005
- Graph analysis of dream reports is especially informative about psychosis Scientific Reports January 15, 2014
- Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide Journal of Psychopharmacology 2016
and 18 more in the library