LSD, afterglow and hangover: Increased episodic memory and verbal fluency, decreased cognitive flexibility.
Isabel Wießner, Rodolfo Olivieri, Marcelo Falchi, Fernanda Palhano-Fontes, Lucas Oliveira Maia, Amanda Feilding, Draulio B Araujo, Sidarta Ribeiro, Luís Fernando Tófoli
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology May 1, 2022 Peer reviewed DOI: 10.1016/j.euroneuro.2022.01.114 via PubMed
Summary
A low dose of 50 μg LSD improved visuospatial memory and phonological verbal fluency while impairing cognitive flexibility in 24 healthy volunteers, measured 24 hours after dosing. Improvements were noted in immediate recall and consolidation tasks, but participants showed fewer categories achieved and more errors in cognitive flexibility tasks. The findings suggest potential therapeutic applications for LSD in conditions affecting memory and language.
Study at a glance
| Design | randomized controlled trial |
|---|---|
| Sample size | 24 |
| Population | healthy volunteers |
| Key finding | LSD sub-acutely improved visuospatial memory and phonological verbal fluency but impaired cognitive flexibility. |
Abstract
Psychedelics acutely impair cognitive functions, but these impairments decline with growing experiences with psychedelics and microdoses may even exert opposing effects. Given the recent evidence that psychedelics induce neuroplasticity, this explorative study aimed at investigating the potential of psychedelics to sub-acutely change cognition. For this, we applied a randomized, double-blind, placebo-controlled, crossover study with 24 healthy volunteers receiving 50 μg lysergic acid diethylamide (LSD) or an inactive placebo. Sub-acute changes in cognition were measured 24 h after dosing, including memory (Rey-Osterrieth Complex Figure, ROCF; 2D Object-Location Memory Task, OLMT; Rey Auditory-Verbal Learning Test, RAVLT), verbal fluency (phonological; semantic; switch), design fluency (basic; filter; switch), cognitive flexibility (Wisconsin Card Sorting Test, WCST), sustained and switching attention (Trail Making Test, TMT), inhibitory control (Stroop Task) and perceptual reasoning (Block Design Test, BDT). The results show that when compared to placebo and corrected for Body Mass Index (BMI) and abstinence period from psychedelics, LSD sub-acutely improved visuospatial memory (ROCF immediate recall points and percentage, OLMT consolidation percentage) and phonological verbal fluency and impaired cognitive flexibility (WCST: fewer categories achieved; more perseveration, errors and conceptual level responses). In conclusion, the low dose of LSD moderately induced both "afterglow" and "hangover". The improvements in visuospatial memory and phonological fluency suggest that LSD-assisted therapy should be explored as a novel treatment perspective in conditions involving memory and language declines such as brain injury, stroke or dementia.