Evolution and Comparative Analysis of Clinical Trials on Psilocybin in the Treatment of Psychopathologies: Trends in the EU and the US

<b>Background/Objectives:</b> This study examines the development of clinical trials investigating psilocybin for the treatment of psychopathologies, with a comparative focus on the United States (US) and the European Union (EU). The objective is to identify regional differences in trial progression, research infrastructure, and regulatory frameworks. <b>Methods</b>: A mixed-methods approach was applied, combining case studies, qualitative and quantitative research. Key variables included trial phase, geographical distribution, demographic factors, funding, governmental support, and public health policies. <b>Results</b>: The US demonstrated a substantially higher number of psilocybin trials across both early and advanced phases. This reflects a strong research infrastructure, growing financial investment, and increasing interest in psychedelic-assisted therapies. In contrast, the EU showed fewer trials and slower advancement, reflecting a more cautious stance that emphasizes patient safety and therapeutic efficacy. These divergences are shaped by differences in regulation, funding mechanisms, and sociocultural attitudes toward psychedelics in psychiatry. <b>Conclusion</b>: This comparative analysis highlights the uneven pace of psilocybin research across different regions. It also emphasizes the importance of international collaboration, harmonization of public health policies, and the development of standardized procedures prioritizing safety and effectiveness. Integrating psilocybin-assisted interventions into psychiatric practice has the potential to expand treatment options and strengthen mental health care, but coordinated global efforts are essential to ensure both scientific rigor and patient protection.