Psilocybin-Assisted Therapy for Treatment-Resistant Depression in Bipolar II Disorder (PAT-BD-01)

This randomised, quadruple-blind, placebo-controlled Phase III trial (n=90) will study the effectiveness, safety, and tolerability of psilocybin (25 mg)–assisted therapy compared to an active placebo (1 mg psilocybin) in individuals with treatment-resistant depression associated with bipolar II disorder.

The study, led by Dr Lakshmi Yatham and conducted at multiple Canadian centres including the University of British Columbia and University of Toronto, targets adults aged 19 to 65 who are currently experiencing a depressive episode and have not improved with at least two standard treatments for bipolar II depression.

Participants will undergo one psilocybin dosing session (either 25 mg or 1 mg) alongside five therapy sessions delivered by trained study therapists. Over a total period of up to 16 weeks (including screening), researchers will assess changes in depression symptoms using the Montgomery–Åsberg Depression Rating Scale (MADRS), alongside other outcomes such as anxiety, functioning, sleep, quality of life, and the presence of any treatment-emergent manic symptoms. This trial will help determine whether psilocybin-assisted therapy is a viable and safe intervention for a population typically excluded from psychedelic research due to concerns over manic episodes.

Topic Treatment-Resistant Depression Depression Bipolar Disorder Safety
Compound Psilocybin Placebo
Country Canada
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Trial Details



Trial Number

Sponsors & Collaborators

University of British Columbia


Data attribution

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