This study is designed to see if psilocybin, a psychedelic compound, is safe for older adults aged 65 to 85. **Psilocybin** is a substance that can cause changes in mood, thinking, and perception. The trial will evaluate how psilocybin affects the body, including blood pressure and heart rhythm. Participants will take two doses of psilocybin 30 days apart. There are two groups receiving different doses: a moderate dose (10mg and then 25mg) and a high dose (15mg and then 30mg). The study will also explore how the body absorbs and processes psilocybin and its impact on thinking and well-being.

• The study involves two visits for dosing, 30 days apart.
• Participants must be healthy and aged 65-85.
• People with certain medical or psychological conditions cannot participate.

To be eligible, participants should not have unstable health conditions or a high risk of blood pressure issues. They should not have any history of serious mental illnesses or active substance use disorders. The study seeks to ensure the safety and well-being of participants by carefully selecting eligible individuals.