Swinburne Three-dose Psilocybin Assisted Psychotherapy (3PAP): a clinical trial of 2 vs 3 doses of psilocybin-assisted psychotherapy vs psychotherapy with placebo for Treatment-Resistant Depression

This randomised, double-blind, 3-arm Phase IIb clinical trial (n=160) investigates two versus three doses of psilocybin-assisted psychotherapy (25mg) vs psychotherapy with placebo for Treatment-Resistant Depression (TRD).

Conducted by Swinburne University of Technology, Hawthorn, Australia, the trial aims to assess the efficacy and safety of two versus three high-dose psilocybin-assisted therapy sessions compared to a placebo for treatment-resistant major depressive disorder (TR-MDD). The intervention arms involve psilocybin doses (25mg) administered with psychotherapy, while the control group receives placebo with psychotherapy.

The primary outcome, measured by the Montgomery-Åsberg Depression Rating Scale (MADRS), is evaluated immediately after the second dosing session (week 5) and at short-term follow-up 3 months after the second dosing session (week 17). Secondary outcomes include long-term sustainability, anxiety, quality of life, employment status, cognitive function, and more.

The trial, funded by Woke Pharmaceuticals, is currently recruiting participants in Australia (QLD, TAS, VIC), with an anticipated completion date of June 2025. The principal investigator is Prof Susan Rossell, and the study is registered on ANZCTR with the registration number ACTRN12623000667617. Ethics approval was granted by the Swinburne University Human Research Ethics Committee on 16/02/2023 (Approval number: 20236919-13556).

Trial Details

This is a 3-arm study using psilocybin-assisted psychotherapy. A randomised controlled, multi-arm design will be used with the same control group all the way through the 57 weeks of the study. Potential participants will be screened to ensure suitability for trial inclusion, and 160 participants will be accepted into the trial upon completion of informed consent. The schedule for all participants will consist of two courses of therapy separated by 4 weeks, each course is comprised of a dosing session plus preparatory and post-integrative psychotherapy sessions with a co-therapist dyad that will generally consist of one female and one male therapist. After the 3-month face to face follow-up session, a third course of therapy (preparatory, dosing, post-integrative) will occur. Participants randomly allocated to the treatment arm will receive an active dose of psilocybin during the first two dosing sessions. Participants in the treatment arm will then be randomly re-allocated to receive either active psilocybin (Arm 1) or an inactive placebo (Arm 2) for the third and final dosing session. Participants allocated to the control group (Arm 3) will receive an in-active placebo at all three dosing sessions. Self-report follow-up assessments will be conducted for all participants every 4 weeks after the first dose-session until 12 months after the second dosing session. Face to face follow-up sessions will occur at 3 months, 6 months and 12 months after the second dosing sessions.

NCT Number ACTRN12623000667617

Data attribution

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