Background Due to inconsistencies in current drug policies and regulatory frameworks, there is a lack of knowledge regarding the adverse event profile of psilocybin mushrooms in Brazil. Our study investigated whether these fungi have potential for abuse and pose a risk to public health.

Methods We conducted a retrospective cross-sectional study following the STROBE Initiative guidelines, using data from the Sistema de Agravos de Notificação (SINAN) to obtain a representative sample of adverse events reported between 2007 and 2022. Participants were divided into three groups: drug abuse, psilocybin mushrooms, and unknown mushrooms. The clinical outcomes evaluated were non-hospitalization, hospitalization, and death. To analyze associations between categorical variables, we applied the Chi-square test (χ²).

Results During the study period, 112,451 individuals sought medical attention due to adverse events associated with drug abuse. Men (n = 79.514; 70.7%), whites (n = 37.565; 33.4%), and the 26-35 age group (n = 29.163; 25.9%) were the most well-represented (p < 0.001). Alcohol (n = 71.824; 49.2%) (p < 0.001) was the primary toxic agent. Hospitalization and mortality rates in the drug abuse group were 19.5% (n = 21,923) and 1.8% (n = 2035), respectively. Psilocybin mushroom group included 13 adverse events, which represents 0.02% of all hospitalizations (n = 6; 46.2%). Unknown mushroom group accounted for 51 adverse events, comprising 0.04% of hospitalizations (n = 12; 23.5%). There were no fatalities in either the psilocybin or unknown mushroom groups. Most hospitalizations involved alcohol (45.0%) and deaths represented mainly by cocaine (33.3%).

Conclusion While our findings suggest that psilocybin mushrooms present a low-risk profile of adverse events, underreporting is a possibility. Given the increasing public interest in psilocybin mushrooms, this study underscores the importance of evidence-based regulatory discussions to prevent arbitrary arrests and ensure safe access to psilocybin for both clinical and ceremonial purposes.

The authors have declared no competing interest.

This study did not receive any funding.

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