Safety and Efficacy of Psilocybin-assisted Psychotherapy for Demoralization Syndrome in Patients Diagnosed With Advanced Stage Cancer

The intervention will be psilocybin-assisted psychotherapy. The first treatment period will include four preparation sessions with Managing Cancer and Living Meaningfully (CALM) therapy elements. The psilocybin dosing session will take place after these preparation sessions are completed. The dosing session will include an in-person visit lasting approximately 8 hours in which the participant will receive a capsule of psilocybin 25 mg under constant supervision of therapists. The following day, the first integration session will take place and two weeks later the second integration session along with CALM will be conducted. Participants who show a partial response will be offered a second dosing session, entering the second treatment period. The second treatment period includes a second dosing session using the same dose and safety measures as the first one. It will also be followed by an integration session the following day, and a second integration session with CALM two weeks later.