The primary objectives of this clinical investigation are to (1) determine the feasibility of
joining psilocybin treatment with CBT (cognitive-behavioral therapy) for patients with
depression, (2) optimize CBT to most effectively integrate the psilocybin experience with
psychotherapy and (3) determine the initial efficacy of psilocybin as an adjunct to
cognitive-behavioral therapy (CBT) for major depressive disorder. Psilocybin will be
administered orally in two doses during the course of 12 sessions of CBT to eligible study
participants - a 10mg dose following the third session and a 25mg dose following the sixth
session. Participants will be in active treatment for the first 4 months (psilocybin + CBT)
of the study and then followed for an additional 3-months following the termination of CBT.