**5. Conclusions**

This work demonstrated that psilocybin may be effective in reducing symptoms of depression and anxiety. The results also showed the presence of publication bias, which, however, do not invalidate the conclusions of this meta-analysis. The obtained results are promising and emphasize the importance of psilocybin translational research that may lead to clinically relevant studies. Mechanistic studies are also needed to clarify the mechanism of action of the drug.

**Author Contributions:** Conceptualization, A.S.V. and E.G.; methodology, Â.L.; validation, M.B.; formal analysis, A.S.V., Â.L., M.B., E.G. and L.P.; investigation, A.S.V. and L.P.; data curation, L.P.; writing—original draft preparation, A.S.V.; writing—review and editing, Â.L.; supervision, E.G. and L.P.; All authors have read and agreed to the published version of the manuscript.

**Funding:** Â.L. acknowledges the contract of Scientific Employment in the scientific area of Microbiology financed by Fundação para a Ciência e a Tecnologia (FCT). This work was partially supported by CICS-UBI, which is financed by National Funds from FCT and Community Funds (UIDB/00709/2020). Authors would also like to thank to "Operação Centro-01-0145-FEDER-000019-C4-Centro de Competências em Cloud Computing," co-financed by the CENTRO 2020 (C4 WP3.1-Data mining for systematic reviews and Meta-Analyses in Health Sciences).

**Conflicts of Interest:** The authors declare no conflict of interest.
