Psilocybin mushrooms and public health in Brazil: a low-risk adverse event profile calls for evidence-based regulatory discussions

Background Current drug policy classifies psilocybin, a substance produced by psychoactive mushrooms, as having a high potential for abuse, neglecting its therapeutic properties. We aimed to investigate if psilocybin mushrooms pose a risk to Brazilian public health compared to other toxic agents and whether evidence-based regulatory discussions are needed. Methods A retrospective cross-sectional study was conducted following STROBE guidelines. Data were obtained from the Sistema de Agravos de Notificação (SINAN) on adverse events reported from 2007 to 2022. Participants were categorized into three groups: drug abuse, psilocybin mushrooms, and unknown mushrooms. Clinical outcomes assessed included non-hospitalization, hospitalization, and death. Associations between variables were analyzed using the Chi-square test. Results A total of 112,451 individuals sought medical attention for drug abuse-related adverse events. Among them, men constituted the majority (n = 79,514; 70.7%), followed by whites (n = 37,565; 33.4%) and those aged 26-35 (n = 29,163; 25.9%) (p < 0.001). Alcohol was the primary toxic agent (n = 71,824; 49.2%) (p < 0.001). The psilocybin mushroom group reported 13 adverse events, and the unknown mushroom group recorded 51 adverse events. Hospitalization rates were 19.5% (n = 21,923) for drug abuse, 46.2% (n = 6) for psilocybin mushrooms (0.02% of all hospitalizations) (99% CI: 10.6% - 81.6%), and 23.5% (n = 12) for unknown mushrooms (0.04% of hospitalizations) (99% CI: 8.3% - 38.7%). The mortality rate was 1.8% (n = 2035) for drug abuse, with no fatalities in the psilocybin or unknown mushroom groups. Most hospitalizations involved alcohol (45.0%), and deaths were mainly associated with cocaine (33.3%). Conclusion Our findings suggest that psilocybin mushrooms have a low-risk profile for adverse events, although underreporting may be a factor. This study highlights the need for evidence-based regulatory discussions to prevent arbitrary arrests and ensure safe access to psilocybin for clinical and ceremonial use.