for people ages 18-55 (full criteria)
at San Diego, California and other locations
study started
estimated completion
Principal Investigator
by Sidney Zisook
Headshot of Sidney Zisook
Sidney Zisook



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).

Official Title

Multicentre Study To Assess Safety And Efficacy Of Psilocybin In Patients With Treatment-Resistant Depression Following Completion Of COMP 001 And COMP 003 Trials (P-TRD LTFU)


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.


Treatment Resistant Depression Depression Depressive Disorder, Treatment-Resistant


You can join if…

Open to people ages 18-55

Signed ICF Each participant having completed the final study visit of either COMP 001 or COMP 003 Ability to complete all protocol required assessment tools (including having access to the internet in order to complete the digital assessments) without any assistance or alteration to the copyrighted assessments, and to comply with all study visits

You CAN'T join if...

Subject has any condition, for which in the opinion of the investigator, participation would not be in the interest of the subject eg participation could compromise the wellbeing of the participant or prevent, limit, or confound the protocol-specified assessments


  • Altman Clinical and Translational Research Institute, University of California accepting new patients
    San Diego California 92093 United States
  • Kadima Neuropsychiatry Institute accepting new patients
    La Jolla California 92037 United States

Lead Scientist at UCSD

  • Sidney Zisook
    Sidney Zisook, M.D., is director of the University of California, San Diego Residency Training Program, and a Distinguished Professor of Psychiatry at UCSD. Dr. Zisook received his Bachelor of Arts from the University of California at Berkeley and his medical degree from Stritch-Loyola, Chicago.


accepting new patients
Start Date
Completion Date
COMPASS Pathways
Study Type
Expecting 150 study participants
Last Updated