Psilocybin Therapy for Psychological Distress in Palliative Patients

The goal of this clinical trial is to evaluate whether psilocybin therapy can effectively treat depression and psychological distress in adult patients with COPD, ALS, MS, or APD who have at least 6 months life expectancy. The main questions it aims to answer are: * Can psilocybin therapy safely reduce depressive symptoms compared to low-dose control? * Will the therapeutic effects be rapid and sustained over a 6-month period? Researchers will compare patients receiving two escalating doses of psilocybin (15mg followed by 25mg) against those receiving two low doses (1mg) to see if the higher doses lead to greater improvements in depression, anxiety, demoralization, and quality of life. Participants will: * Attend three preparation sessions with psychotherapists (1-2 hours each) * Undergo two supervised psilocybin dosing sessions (6-8 hours each) * Complete five integration therapy sessions following the dosing sessions * Participate in follow-up assessments at 6 weeks, 3 months, and 6 months * Have access to a digital care platform and peer support groups during the 6-month follow-up period * Optional: Control group participants may receive one high-dose psilocybin session (25mg) after the initial study period