This trial is designed to evaluate efficacy and psychological mechanisms of single-dose psilocybin-assisted psychotherapy (PAP) to treat psychiatric (anxiety, depression) and existential distress (demoralization, death anxiety), and quality-of-life (QOL), in 200 outpatients with late-stage or advanced cancer. The study will assess the strength and durability of therapeutic effects in a double-blind, parallel-design, placebo-controlled, two-center RCT comparing a single 25mg oral 'high' dose of psilocybin to a single 100mg dose of niacin (active placebo), both delivered in conjunction with a psychotherapy platform.
The purpose of this research is to study the safety and effects of single-dose psilocybin 25mg versus an active placebo (single dose niacin 100mg) in the treatment of anxiety, depression, and existential distress (i.e., loss of meaning and hope; fear of death) in advanced cancer (i.e., stage 3 or 4). Study medications will be administered in conjunction with brief psychotherapy that is designed to treat anxiety, depression and existential distress in advanced cancer.