Psilocybin-Assisted Therapy for Treatment-Resistant Depression in Bipolar II Disorder

Starting soon · Phase 3 · Has a placebo group

Conditions studied: Bipolar II Depression

In brief

This study is a 12-week (in addition to up to 30 days of screening) randomized, double-blind, placebo-controlled, parallel-group trial. The primary objective of this study is to assess the effectiveness, safety, and tolerability of single-dose psilocybin (25 mg)-assisted therapy in comparison to active placebo (1 mg micro-dose) psilocybin-assisted therapy in patients with bipolar II depression who have not responded to adequate trials with at least two first or second-line treatments for bipolar II depression (i.e. quetiapine, lithium, lamotrigine, sertraline, or venlafaxine as monotherapy or adjunctive therapy, or bupropion adjunctive therapy). The active placebo is a substance that looks identical to the study medication but contains less therapeutic ingredients, and thus is less capable of producing the transformative and meaningful aspects of psychedelic experience compared to the 25 mg dose. Participants will have a total of 11 study visits over a period of up to 16 weeks, which includes 5 therapy sessions from trained study therapists.

Key facts

Study ID

NCT06943573

Run by

Lakshmi N Yatham

People needed

90

Starts

2026-05-01

Expected to finish

2028-12-01

Last updated by the study team

2026-05-01

Who can join

Age: 19 and older, up to 65. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• You are male or female aged 19 to 65 years inclusive.
• You have a diagnosis of bipolar disorder type II, and are currently in a major depressive episode.
• You are willing, for the entire duration of the study, to practice highly effective methods of contraception (e.g., contraceptive pills, intrauterine device or system, vasectomy and tubal ligation, or double-barrier methods of contraception) OR agree to completely abstain from heterosexual intercourse. Females who do not have childbearing potential are required to be postmenopausal for at least 1 year before the screening visit (confirmed by an FSH test) OR surgically sterile.
• You have sufficient English language skills to understand, consent to, and comply with study requirements, study visits, and to return to the clinic for follow-up evaluations.
• Your current medications have been at a stable dose for two weeks prior to the dosing visit.

You may not qualify if…

• You have a history of psychotic symptoms.
• You have a history of seizures.
• You have a current unstable or inadequately treated medical illness, especially cardiovascular illness, except for the current depression.
• You recently (i.e., within the past 6 weeks) started taking treatment for your acute bipolar depressive episode.
• You recently (i.e., within the past 8 weeks) began structured psychotherapy (e.g., cognitive-behavioral therapy, interpersonal psychotherapy, family-focused therapy, or interpersonal and social rhythm therapy).
• You have a history of nonresponse or intolerance to psilocybin.
• You have, in the past 6 months, used any psychedelic drugs, including ketamine, LSD, or psilocybin-containing mushrooms.
• You have a history of non-response to electroconvulsive therapy.
• You are pregnant or lactating.

Where it is running

• Djavad Mowafaghian Centre for Brain Health — Vancouver, British Columbia, Canada
• Department of Psychiatry, University of Ottawa, The Ottawa Hospital — Ottawa, Ontario, Canada
• Department of Psychiatry, University of Toronto, University Health Network, — Toronto, Ontario, Canada

Full record on ClinicalTrials.gov

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