BACKGROUND: Taking very small doses of psychedelics (LSD, truffles) over an extended period became prevalent in Western societies for its alleged cognitive benefit, including enhanced creativity. However, in the absence of robust, double-blind-controlled quantitative studies, such claims remain anecdotal.
METHODS: Here we present results from 3 double-blind placebo-controlled longitudinal trials (one of which pre-registered) assessing the effects of microdosing psilocybin on convergent and divergent creativity in a well-controlled semi-naturalistic setting. To enhance statistical power and generalizability, data from all trials (N = 171) were pooled in a mega-analysis, resulting in one of the most robust laboratory-based studies on microdosing to date.
RESULTS: We found that active microdosing increased the ratio of original responses (originality/fluency), indicating higher quality of divergent thinking in the active microdosing condition. The unadjusted originality score was significantly more pronounced in the active microdosing condition, but only when relative dosage (dose/weight of participants) was considered. Importantly, these effects survived controlling for dose guess and demographic biases. No effects of active microdosing were found for other divergent-thinking scores or convergent thinking.
CONCLUSION: The results suggest that the effects of truffle mirodosing are limited to the quality of divergent thinking. Moreover, our findings highlight the importance of controlling for placebo effects and prior psychedelic experience in assessing the impact of microdosing.
