Psilocybin microdosing fails to boost cognitive performance in rigorous trials

Psilocybin microdosing does not improve cognitive performance or mood in rigorous, randomized, double-blind placebo-controlled longitudinal trials. Two studies in the Netherlands used psilocybin-containing truffles with healthy volunteers who were screened for mental health issues. Participants took doses on a schedule over several weeks (about 0.65 g per dose for roughly four weeks in the first study, and about 1 g per dose for eight weeks in the second), while completing cognitive tasks that probed attention, memory, and task switching. Results showed no consistent advantages over placebo on memory, focusing, or cognitive flexibility. Any small differences (such as a social cognition change) were not statistically reliable after correcting for multiple comparisons. The only more consistent effect was increased negative physical sensations in the psilocybin group, including discomfort and nausea, suggesting the drug was pharmacologically active even without cognitive benefits. The findings challenge claims that microdosing provides a real “glow” in healthy people and point to placebo-driven expectations as a likely explanation for prior positive reports.