RecruitingPHASE2INTERVENTIONAL

Subjective Experience Following Psilocybin

This study is exploring how the mind-altering experiences caused by psilocybin, found in 'magic mushrooms', might help people feel better. Researchers want to understand if these powerful subjective effects are actually needed for the drug to work. To do this, participants will receive either a high or low dose of psilocybin. Some will also take a different medicine called risperidone, which is expected to block the mind-altering effects of psilocybin. Others will receive a dummy pill (placebo). The study will look at how people feel and their stress levels to see if blocking the psychedelic experience changes the effects of psilocybin, both immediately and weeks later. This will help us understand more about how psilocybin works.

At a glance

Status

Recruiting

Phase

PHASE2

Sponsor

University of Calgary

Enrolment target

128

Start

15 May 2026

Estimated completion

01 Jan 2028

Investigating the Importance of the Subjective Psychedelic Experience

What is this study about?

This research study is all about understanding how a substance called psilocybin, which comes from certain 'magic mushrooms', affects people. We're especially interested in the powerful, mind-altering experiences people have when they take it, known as the 'subjective psychedelic experience'. The main question is: are these unique experiences actually important for psilocybin to have positive effects on a person's well-being and stress levels?

To figure this out, some participants will receive psilocybin. Others will also be given a medicine called risperidone. Risperidone is known to block, or lessen, these mind-altering effects. By comparing people who experience the full psychedelic effects with those whose experience is blocked, we can learn if the subjective journey is necessary for any positive changes. We'll be looking carefully at how people feel, their stress reactions, and even some markers in their blood, both right after taking the drug and in the weeks that follow.

The study also wants to see if certain things about a person, like how they usually handle stress, might affect how they respond to psilocybin. This will help us understand why different people might react differently to the same dose. This study is being done in one location and involves 128 people who are generally healthy and don't have any current mental health conditions.

Key takeaways

This study explores if the 'mind-altering trip' from psilocybin is needed for it to help people.
Participants will get either psilocybin (high or low dose) with a dummy pill or a drug called risperidone.
Risperidone is used to see if blocking the psychedelic experience changes how psilocybin works.
It's for healthy adults aged 18-65 with no current major mental health conditions.
Participation involves health checks, a dosing session, and follow-up checks over one month.
Your involvement helps us understand psilocybin better, but there's no guaranteed personal benefit.

Who may be eligible?

This study is looking for a diverse group of people, aged between 18 and 65, who can read and write in English. To make sure the results are clear, they are looking for people who are currently in good mental and physical health.

There are several reasons why someone might not be able to join. For example, if you have a history of certain mental health conditions, such as depression, anxiety, schizophrenia, or bipolar disorder, or if these conditions run in your close family, you likely won't be eligible. Also, if you're taking medications that could react with the study drugs, or if you're pregnant, breastfeeding, or planning to get pregnant, you won't be able to take part.

They will also check your general health with tests like blood work and heart scans (ECG). If there are any significant health issues or if you've recently had a head injury with specific symptoms, this might prevent you from joining. It's important that you also agree not to use psychedelic drugs during the study or other psychoactive drugs right before the dosing sessions.

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 18 and 65 years old?
Do you have good overall physical and mental health?
Do you currently NOT have any major mental health conditions like depression, anxiety, or bipolar disorder?
Do you NOT have a close family member (parent, sibling, child) with a history of psychosis or bipolar disorder?
Are you NOT pregnant, breastfeeding, or planning to become pregnant?
Are you NOT taking medications that could interfere with the study drugs (e.g., SSRIs, certain antipsychotics)?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll first go through some checks to see if you're suitable. This includes filling out questionnaires, having blood tests, and a medical check-up, including an ECG to check your heart. Once accepted, you'll complete some initial assessments to measure things like your mood, stress levels, and thinking skills.

After these initial checks, you'll be randomly put into one of four groups. This means neither you nor the doctors will choose which group you're in, similar to a coin toss. You could receive a high or low dose of psilocybin. Alongside this, you'll either get a dummy pill (placebo) or the medicine risperidone. You'll then have a dosing session.

After your dosing session, researchers will check in with you again one week later and then one month later. These follow-up visits will involve similar measurements to see how the psilocybin has affected you over time. The study will take place at a single location.

Potential risks and benefits

Taking part in any study has potential benefits and risks. You might not receive any direct benefit from taking part in this specific study, but your participation will help doctors and scientists learn more about how psilocybin works and if the psychedelic experience is important for its effects. This knowledge could help others in the future. Potential risks might include experiencing side effects from the study drugs, and the psychological experience of psilocybin can sometimes be intense or uncomfortable for some individuals. All medical procedures and drugs have potential risks, though trained staff will be on hand. You should know that taking part in this study is entirely voluntary, and you have the right to withdraw at any time without giving a reason.

Locations (1)

University of Calgary
Verified postcode
Calgary, Canada· Recruiting

Common questions

What is psilocybin?

Psilocybin is a natural substance found in certain types of mushrooms, sometimes called 'magic mushrooms'. It can cause changes in how you think, feel, and see things.

What is risperidone?

Risperidone is a medicine sometimes used to treat serious mental health conditions. In this study, it's being used to see if it can block or lessen the mind-altering effects of psilocybin.

Will I know if I'm getting psilocybin or a placebo?

No, because the study is 'blinded'. Neither you nor the study team will know which treatment you are receiving until after the study is complete. This helps ensure the results are fair.

How long will I be involved in the study?

After your initial checks and the dosing session, you will have follow-up visits one week and one month later. The total duration of your participation will be from your first assessment until the final follow-up.

Can I stop participating if I want to?

Yes, taking part is completely voluntary. You can decide to leave the study at any time, for any reason, without it affecting your medical care.

How to find out more

Ana Deutsch, MSc

ana.deutsch@ucalgary.ca 587-893-0257 Official trial record

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