Not yet recruitingPHASE3INTERVENTIONAL

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

This study is investigating a new approach for people in the UK with Bipolar II Depression, especially those who haven't responded well to standard treatments. We're exploring psilocybin-assisted therapy, where a single dose of psilocybin (a natural compound from certain mushrooms) is given alongside support from specially trained therapists. The main goal is to see how safe and effective this treatment is compared to a very low dose of psilocybin, which acts as a comparison. The study lasts about 12 weeks, with screening before that, and involves several visits to the clinic for therapy and check-ups. We hope to find a new way to help people suffering from persistent depression caused by Bipolar II Disorder.

At a glance

Status

Not yet recruiting

Phase

PHASE3

Sponsor

Lakshmi N Yatham

Enrolment target

Start

01 May 2026

Estimated completion

01 Dec 2028

Bipolar II Depression

What is this study about?

Bipolar II Disorder is a lifelong condition that causes people to experience significant swings in their mood, from periods of very high energy (hypomania) to long periods of deep depression. Many people with Bipolar II Disorder spend a lot of their time feeling depressed, even when they're receiving treatment. This is why doctors and researchers are always looking for new and more effective ways to help.

This study is looking into whether psilocybin-assisted therapy could be a useful new treatment. Psilocybin is a natural substance found in certain mushrooms. When given in a carefully controlled environment, and with support from therapists, it has shown promise in helping people feel better and improve their outlook. We want to test if a specific dose of psilocybin (25 mg) combined with therapy is better at helping people with Bipolar II Depression than a very small 'micro-dose' (1 mg) intended as a comparison treatment.

The study aims to understand how well psilocybin works, if it's safe, and if people can tolerate it. It's specifically for those who have tried at least two other common treatments for Bipolar II Depression (like certain medications) and haven't found sufficient relief. By carefully comparing the two doses, we hope to gather strong evidence to see if this approach could offer a new option for those who are struggling.

Key takeaways

Exploring psilocybin-assisted therapy for persistent Bipolar II Depression.
Specifically for those who haven't responded to at least two other standard treatments.
Compares a single psilocybin dose (25 mg) with a very low micro-dose (1 mg), alongside therapy.
Involves 11 clinic visits over up to 16 weeks, including 5 therapy sessions.
Aims to understand how safe and effective this new approach is.
Joining is voluntary, and you can withdraw at any time.

Who may be eligible?

This study is looking for men and women aged between 19 and 65 years old. You would need to have been diagnosed with Bipolar II Disorder and currently be experiencing a significant depressive episode. It's important that you have sufficient English skills to understand the study, give your consent, and follow all the instructions and attend appointments.

For the safety of participants, there are also some specific requirements around contraception for those who can have children, or for women who are past menopause. Also, any medications you are currently taking must have been at a stable dose for at least two weeks before starting the study.

There are also some reasons why you wouldn't be able to join. For example, if you have a history of certain mental health issues like psychosis or seizures, or if you have serious untreated heart problems. If you've recently started new depression treatments or therapy, or if you've used other psychedelic drugs in the past six months, you wouldn't be eligible. Also, if you are pregnant or breastfeeding, this study would not be suitable for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 19 and 65 years old?
Do you have a diagnosis of Bipolar II Disorder and are currently feeling depressed?
Have you tried at least two other treatments for Bipolar II depression without enough success?
Are you able to understand and speak English well enough for study activities?
For women, are you not pregnant or breastfeeding, and would you use effective contraception during the study?
Do you have a stable dose of any current medications for at least two weeks?

Answer every question to see your result.

What does participation involve?

If you join this study, it will involve a total of 11 visits to the study clinic over a period of up to 16 weeks, following an initial screening period of up to 30 days. You'll receive either a single dose of psilocybin (25 mg) or a very low 'micro-dose' (1 mg) as a comparison. This will be given in a controlled setting, and you won't know which dose you've received, nor will the study staff who are directly treating you.

Alongside the medication, you will have five therapy sessions with specially trained study therapists. These sessions are designed to support you throughout the process. Over the course of the study, you'll have regular check-ups and assessments to monitor your well-being, the effects of the treatment, and any changes in your depression. The overall commitment from your side, including screening and follow-up, could be up to 16 weeks.

Potential risks and benefits

Participating in this study could offer the potential benefit of trying a new therapy that might help improve your depression symptoms, especially if other treatments haven't worked for you. However, it's important to remember that this is a research study, and there's no guarantee that you will personally benefit. Potential risks include experiencing temporary changes in perception or mood during the psilocybin session, though this is managed with therapist support. There might also be other side effects, which will be carefully monitored. You will be fully informed of all potential risks before deciding to join, and you have the right to withdraw from the study at any time, for any reason, without it affecting your usual medical care.

Locations (3)

Djavad Mowafaghian Centre for Brain Health
Verified postcode
Vancouver, Canada
Department of Psychiatry, University of Ottawa, The Ottawa Hospital
Verified postcode
Ottawa, Canada
Department of Psychiatry, University of Toronto, University Health Network,
Verified postcode
Toronto, Canada

Common questions

What is psilocybin?

Psilocybin is a natural compound found in certain types of mushrooms that can change your perception and mood. In this study, it's being used under strict medical supervision and with therapy support.

What is Bipolar II Depression?

It's a type of Bipolar Disorder where people have periods of low mood (depression) and shorter periods of increased energy (hypomania). The depression often lasts a long time.

Will I know if I get the active dose or the comparison dose?

No, this is a 'double-blind' study, meaning neither you nor the staff giving the treatment will know if you receive the higher dose or the very low comparison dose. This helps ensure the results are fair.

How long will I need to be involved?

The study itself lasts about 12 weeks, plus an initial screening period of up to 30 days. In total, you could be involved for up to 16 weeks, including follow-up visits.

Can I continue my current medications?

Generally, yes, as long as your current medications have been at a stable dose for at least two weeks before you start the main part of the study. This will be discussed in detail during screening.

How to find out more

Vy Ngo, B.Sc

vy.ngo@ubc.ca 604-822-3769 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.