Natural language signatures of psilocybin microdosing
This double-blind placebo-controlled trial (n=34) assessed natural language as a resource to identify speech produced under the acute effects of psilocybin microdoses (0.5g dried mushroom), focusing on variables known to be affected by higher doses: verbosity, semantic variability and sentiment score. Verbosity and sentiment scores significantly differed between groups suggesting that microdosing can be identified from natural speech.
Authors
- Enzo Tagliazucchi
- Claudio Pallavicini
- Michal Kuchar
Published
Abstract
Serotonergic psychedelics are being studied as novel treatments for mental health disorders and as facilitators of improved well-being, mental function and creativity. Recent studies have found mixed results concerning the effects of low doses of psychedelics (microdosing) on these domains. However, microdosing is generally investigated using instruments designed to assess larger doses of psychedelics, which might lack sensitivity and specificity for this purpose. Following a double-blind and placebo-controlled experimental design, we explored natural language as a resource to identify speech produced under the acute effects of psilocybin microdoses, focusing on variables known to be affected by higher doses: verbosity, semantic variability and sentiment scores. Except for semantic variability, these metrics presented significant differences between a typical active microdose of 0.5 g of psilocybin mushrooms and an inactive placebo condition. Moreover, machine learning classifiers trained using these metrics were capable of distinguishing between conditions with high accuracy (AUC close to 0.8). Our results constitute first proof that low doses of serotonergic psychedelics can be identified from unconstrained natural speech, with potential for widely applicable, affordable, and ecologically valid monitoring of microdosing schedules.
Research Summary of 'Natural language signatures of psilocybin microdosing'
Introduction
Psychedelic microdosing involves taking small amounts of serotonergic compounds, typically about 10-20% of a full dose, with users reporting improvements in mood, productivity and cognition. The evidence base is mixed: observational and open-label studies frequently report benefits but are prone to expectancy and selection biases, while double-blind placebo-controlled trials have produced weaker support. The authors argue that standard questionnaires and tasks—often designed for full psychedelic doses—may lack the sensitivity and specificity needed to detect the subtler acute effects of microdoses, creating a need for alternative, more sensitive measurement approaches. Sanz and colleagues therefore investigated whether natural language produced during the acute effects of a psilocybin microdose could reveal objective signatures of drug action. Using a double-blind, placebo-controlled within-subject design, they extracted three speech-based metrics previously linked to higher psychedelic doses—verbosity, semantic variability and mean sentiment score—and tested whether these measures differed between a typical microdose (0.5 g dried Psilocybe cubensis) and placebo. They also trained machine learning classifiers on these features to determine whether speech alone could discriminate active vs placebo and explore the role of participant unblinding (correctly guessing condition).
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Study Details
- Study Typeindividual
- Journal
- Compound
- Topics
- Authors
- APA Citation
Sanz, C., Cavanna, F., Muller, S., de la Fuente, L., Zamberlan, F., Palmucci, M., Janeckova, L., Kuchar, M., Carrillo, F., García, A. M., Pallavicini, C., & Tagliazucchi, E. (2022). Natural language signatures of psilocybin microdosing. Psychopharmacology, 239(9), 2841-2852. https://doi.org/10.1007/s00213-022-06170-0
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