This was the first double-blind and placebo-controlled study (n=48) into the effects of microdosing LSD. The topic was quite specific (time perception), but they also reported on other cognitive changes (of which there were few and a very small scale).

Abstract of The effects of microdose LSD on time perception

“Rationale Previous research demonstrating that lysergic acid diethylamide (LSD) produces alterations in time perception has implications for its impact on conscious states and a range of psychological functions that necessitate precise interval timing. However, the interpretation of this research is hindered by methodological limitations and an inability to dissociate direct neurochemical effects on interval timing from indirect effects attributable to altered states of consciousness.

Methods We conducted a randomised, double-blind, placebo-controlled study contrasting oral administration of placebo with three microdoses of LSD (5, 10, and 20 μg) in older adults. Subjective drug effects were regularly recorded, and interval timing was assessed using a temporal reproduction task spanning subsecond and supra-second intervals.

Results LSD conditions were not associated with any robust changes in self-report indices of perception, mentation, or concentration. LSD reliably produced over-reproduction of temporal intervals of 2000 ms and longer, with these effects most pronounced in the 10 μg dose condition. Hierarchical regression analyses indicated that LSD-mediated over-reproduction was independent of marginal differences in self-reported drug effects across conditions.

Conclusions These results suggest that microdose LSD produces temporal dilation of suprasecond intervals in the absence of subjective alterations of consciousness.“

Authors: Steliana Yanakieva, Naya Polychroni, Neiloufar Family, Luke T. J. Williams, David P. Luke & Devin B. Terhune

Notes on The effects of microdose LSD on time perception

This paper was included in a systematic review on microdosing psychedelics by Ona & Bouso (2020).

Data from this study was further analysed by Family et al. (2019).

Summary of The effects of microdose LSD on time perception

Time perception is important for momentary updating and integration of perceptual information in working memory, and is distorted in altered states of consciousness and psychiatric disorders.

Under lysergic acid diethylamide (LSD), subjects have been shown to have subjective distortions in time perception and to have increased variability in interval timing for 1 min intervals.

LSD alters human interval timing, potentially through 5-HT2A-mediated inhibition of dopamine, which is believed to play an important mechanistic role in the perception of time. This finding may contribute to or underlie the broader cognitive and perceptual effects of LSD.

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Find this paper

The effects of microdose LSD on time perception: a randomised, double-blind, placebo-controlled trial

https://doi.org/10.1007/s00213-018-5119-x

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Cite this paper (APA)

Yanakieva, S., Polychroni, N., Family, N., Williams, L. T., Luke, D. P., & Terhune, D. B. (2019). The effects of microdose LSD on time perception: a randomised, double-blind, placebo-controlled trial. Psychopharmacology, 236, 1159-1170.

Study details

Compounds studied
LSD

Topics studied
Microdosing Healthy Subjects

Study characteristics
Original Placebo-Controlled Double-Blind Randomized Re-analysis

Participants
48 Humans

Institutes

Institutes associated with this publication

Eleusis
Eleusis is a clinical-stage life sciences company that studies and develops psychedelic drugs for therapeutic use. Since 2013 the company has been researching psychedelics and is now developing ELE-Psilo (psilocybin) for depression that is in Phase I.

Compound Details

The psychedelics given at which dose and how many times

LSD 5 - 20
μg | 1x

Linked Research Papers

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LSD microdosing attenuates the impact of temporal priors in time perception
This pre-print re-analysis (n=48) of microdosing LSD (5-20μg) finds that LSD reduces the influence of our expectations (precision-weighted local priors) on what we think time should feel like (under-reproduction bias). When controlling for the expectations, the bias disappears, indicating that LSD microdosing reduces the relative weighting of priors (expectations).

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