Long disregarded as a party drug, loved by hippies and alternative thinkers, LSD has been recently demonstrated to be much more than that, being useful as an anti-depressive and in therapy against PTSD and other traumas. Now, another “power” of LSD has been uncovered: it potentiates brain plasticity, thereby improving memory and other cognitive processes.
A recently published work 1 by Sidarta Ribeiro and colleagues has shown that LSD has positive effects on memory, and that this is mediated by brain plasticity. First, the researches performed behavioural experiments in both rats and humans to test memory after receiving LSD. In a novel object preference test, rats which received a single dose of LSD spent more time investigating new objects than rats which received saline. This indicates that LSD improved memory and cognition in rats, as preference for novel items instead of known ones is an indication for it.
To see how these effects translate to humans, they run a randomized, double-blind, placebo-controlled study in 25 participants which had already tried LSD, and given them alternatively and randomly a placebo or an LSD dose in two test sessions. These test sessions used two behavioural tests, a visuospatial 2D object-location task and a Rey-Osterrieth Complex Figure test, to assess memory formation and consolidation. When receiving LSD, participants outperformed themselves when only receiving placebo, showing that a single dose was already enough to produce brain plasticity and improve memory.
To look deeper into the mechanism responsible for these improvements in memory, the investigators performed in vitro experiments in organoids, 3D biological structures derived from stem cells and which better resemble organs like the brain than simple cell culture. The experiments showed changes to various metabolic pathways including changes to mTOR expression levels. Since this protein is involved in numerous biological processes like plasticity and learning and memory, the authors conclude that LSD’s effects on memory are mediated by plasticity.
Despite these encouraging results, it is soon to start popping LSD tablets into your mouth like candy. More research is needed into sex, or age differences, and the effects of the setting, which is known to greatly affect psychedelic experiences and determining the nature of the “trip”.