AuthorisedTherapeutic exploratory (Phase II)Interventional

POSITRON - PsilOcybin with pSychologIcal supporT foR cOcaiNe: a randomised controlled pilot feasibility trial of psilocybin with psychological support for cocaine use disorder

This research, called POSITRON, is exploring a new approach to help people who are struggling with cocaine addiction. It's a pilot study, which means it’s an early step to see if a larger study would be possible and how it would work. Participants will receive either a dose of psilocybin (often associated with 'magic mushrooms') or a common sleep aid (which acts as a comparison) alongside psychological support. The main goal is not to prove if the treatment works yet, but to understand things like how easy it is to find people for the study, whether they agree to take part, and if they stick with the treatment. This will help scientists plan future, larger studies more effectively.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Trinity College Dublin

Enrolment target

Start

27 Feb 2026

Cocaine addiction

What is this study about?

The POSITRON study is investigating a new way to help individuals who are living with cocaine addiction. This type of research is called a 'pilot feasibility trial,' which means it's an important early step. It's not about finding out if the treatment definitely cures addiction at this stage. Instead, researchers want to learn if it's practical to run a full-scale study later on.

Participants in this study will receive either psilocybin, which is the active compound found in some types of mushrooms, or a common sleep medication called diphenhydramine. Both treatments will be given alongside psychological support, which involves talking therapies. Researchers will be looking at how well they can recruit people, if people are happy to join, and if they complete the study. They also want to understand why some people might drop out.

While the main focus is on how feasible the study is to run, researchers will also be gathering some initial information about participant well-being. This includes tracking how many days people manage to stay away from cocaine, how they are feeling emotionally (like mood and anxiety), and how the treatment might affect their daily lives. They will also carefully monitor any side effects to make sure the treatment is safe.

Key takeaways

This is an early-stage study (pilot feasibility trial) for cocaine addiction.
It's testing psilocybin with talking therapy against a sleep aid with talking therapy.
The main aim is to see if a larger study is practical to run, not if the treatment cures addiction yet.
Participants will be carefully monitored for safety and well-being.
The study involves psychological support alongside medication.
You can withdraw from the study at any time if you decide it's not for you.

Who may be eligible?

This study is open to both men and women who are 18 years old or older. There isn't an upper age limit mentioned, so older adults could also be considered.

To be eligible, you would likely need to have been diagnosed with cocaine addiction. The study will have specific criteria that you'd need to meet, for example, about your current drug use patterns or your general health. These details would be checked by the study team.

There may also be specific reasons why someone wouldn't be able to join, such as certain medical conditions, mental health issues, or other medications they are taking. The study team would discuss all these points with you to make sure it's safe for you to take part.

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 18 years old or older?
Have you been diagnosed with cocaine addiction?
Are you able to attend appointments regularly?
Are you willing to discuss your cocaine use and feelings with the study team?
Are you comfortable potentially receiving either psilocybin or a sleep aid?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you would first go through a screening process to check if the study is right for you. If you're eligible, you would then be randomly assigned to receive either psilocybin (25mg) or diphenhydramine (100mg), which is a common sleep aid. This is done by chance, like flipping a coin, so neither you nor the study team can choose which treatment you get. Both treatments will be given with psychological support.

You would have several visits to the clinic for your treatment and assessments. These assessments would involve answering questions about your cocaine use, mood, anxiety, and general well-being. You might also be asked to provide urine samples and have basic health checks like blood pressure, heart rate, and blood tests. Researchers would also be interested in how you experience the treatment sessions themselves. The study will track you for a period after the main treatment to see how you are doing over time. The total duration of your participation, including follow-up, will be explained in detail by the study team.

Potential risks and benefits

Taking part in any clinical trial has potential benefits and potential risks. While this study's main aim is to understand how practical it is, you might experience some early benefits from the psychological support and potentially from the active treatments themselves, such as a reduction in cocaine craving or improved mood. However, there's no guarantee that you will personally benefit. Potential risks could include side effects from the medication (like nausea, dizziness, or changes in heart rate/blood pressure for psilocybin, or drowsiness for diphenhydramine) or emotional discomfort during the psychological sessions. All side effects will be carefully monitored by the study team. You have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Ireland

Common questions

What is psilocybin?

Psilocybin is a natural substance found in certain types of mushrooms. It can affect how you think, feel, and sense things. In this study, it's given under very controlled conditions with medical supervision.

What is a 'pilot feasibility trial'?

This type of trial is an early stage of research. It helps scientists learn if a larger study on a new treatment is possible and how best to design it. It's not designed to prove if the treatment works yet, but to check practical things like recruitment and participation.

Will I know if I'm getting psilocybin or the sleep aid?

No, it's a 'blinded' study, meaning neither you nor the doctors treating you will know which medication you receive. This helps ensure the results are fair and unbiased.

What kind of 'psychological support' will be offered?

The study will include talking therapy sessions designed to help you explore your thoughts and feelings, especially in relation to your cocaine use. The specific type of therapy will be explained by the study team.

How long will I be involved in the study?

The exact duration will be explained by the study team. It will involve treatment sessions and follow-up appointments over a period of time to see how you are doing.