SPEAKERS

Background: Since a decade, there has been an increased interest in the practice of microdosing with psychedelics such as LSD. A microdose is by definition sub-perceptual, suggested to be one-tenth of a ‘regular dose’ and used according to a specific schedule to enhance mood and/or performance. However, users indicate that they do not know the exact dose they actually consume when inducing the aforementioned effects. Therefore, the main objective was to determine the effective dose which positively affects mood and cognition.

Methods: A placebo-controlled within-subjects study including 24 healthy recreational drug users was set up to test the acute effects of three different microdoses of LSD (5, 10, and 20 mcg, p.o.) compared to placebo on measures of cognition (attention) and subjective experience (mood).

Results: The highest dose (20 mcg) significantly enhanced attention and increased self-rated positive mood and happiness while impairing performance of a more complex shifting task and decreasing self-rated levels of concentration and productivity compared to placebo. The intermediate (10 mcg) dose increased the feeling of productivity. Participants noticed they were under the influence of LSD after the high and intermediate microdose and a slight increase in psychedelic state was experienced.

Conclusion: While findings show that a single LSD dose of 20 mcg acutely enhances subjective (mood) effects and attention, more complex cognitive performance is impaired and perceptual effects are experienced. Future studies need to establish whether these effects are persisting beyond the acute stage and whether effects change after repeated administration.