In this present study (COMP 004), the aim is to follow up participants from COMP 001 and COMP 003 in a long-term follow up study, with both remote and digital assessments, to explore the long term efficacy and safety of the three different doses of psilocybin (1 mg, 10 mg, and 25 mg) administered to patients with TRD as a monotherapy in COMP 001 and 25 mg psilocybin administered as an adjunct to an SSRI in COMP 003. Patients previously treated in COMP001 will be followed for approximately 40 weeks and patients previosuly treated in COMP003 will be followed for approximately 49 weeks giving a total follow up period of 52 weeks from psilocybin dosing.
The primary objective of this study is to assess the long-term efficacy of psilocybin with respect to use of new antidepressant treatment, hospitalisations for depression, suicidality, and depressive severity rated using the Montgomery and Asberg Depression Rating Scale (MADRS) over a total of 52 weeks (compared across the 1 mg, 10 mg and 25 mg psilocybin groups from COMP 001).