RecruitingNAINTERVENTIONAL

Investigating the Neural Correlates of Cognitive Function in Psychosis Patients and Non-Psychiatric Controls With Cannabis Use

This study aims to understand how using cannabis affects thinking and memory in people who have psychosis, as well as in others who use cannabis but don't have psychosis. We know that thinking problems are common in people with psychosis and can be linked to cannabis use. Researchers are looking into the brain changes that happen after someone stops using cannabis for 28 days. Participants will have brain scans before and after this period. The goal is to find out if taking a break from cannabis can help improve memory and other brain functions, and to learn more about how the brain recovers. This information could help develop better ways to support people who struggle with problematic cannabis use.

At a glance

Status

Recruiting

Phase

Sponsor

Douglas Mental Health University Institute

Enrolment target

134

Start

21 Apr 2022

Estimated completion

01 May 2027

Psychotic Disorders Cannabis Use Disorder Cannabis Dependence Cannabis Use Schizophrenia; Psychosis Cognitive Dysfunction Memory Impairment Neuroimaging

What is this study about?

This study is investigating how using cannabis affects people's thinking and memory, especially if they have psychosis. Even for people without psychosis, cannabis can impact brain function. Researchers want to understand exactly what happens in the brain when someone uses cannabis, and more importantly, what changes occur if they stop using it for a period.

To do this, the study will involve two main groups: people who have psychosis and use cannabis, and people who use cannabis but do not have psychosis. Some participants will be asked to stop using cannabis for 28 days, while others will continue using it as usual. Everyone will have special brain scans (called MRI scans) and memory tests at the start of the study and again after 28 days. These scans help doctors see how the brain is structured and how it works during tasks like remembering things.

The main aim is to see if taking a break from cannabis for 28 days can improve memory and brain activity. The study also hopes to learn if certain brain patterns can predict who might find it easier to stop using cannabis. By understanding these brain changes, researchers hope to develop better support and treatments for people who are finding cannabis use problematic.

Key takeaways

The study explores how cannabis affects memory and brain function in people with and without psychosis.
It investigates if 28 days without cannabis can improve cognitive abilities.
Brain scans (MRI) and memory tests are used before and after the 28-day period.
Participation involves either stopping cannabis for 28 days or continuing as usual.
The aim is to develop better support for problematic cannabis use.
You must be 16-80 years old and meet specific health criteria to take part.

Who may be eligible?

This study is looking for volunteers between 16 and 80 years old. You need to be able to understand and sign consent forms in English or French.

For most people, you must use cannabis weekly for at least six months, or have a diagnosis of cannabis use disorder. Your IQ should be 75 or higher. If you have psychosis, you must also be an outpatient, taking a steady dose of medication for at least two months, and your symptoms should be stable. However, if you don't have psychosis, you can't have other major mental health diagnoses or be taking certain medications.

There are also some reasons why you might not be able to join. These include having other serious drug use issues (apart from cannabis), having metal in your body that would prevent an MRI scan, or testing positive for other drugs besides cannabis, nicotine, or caffeine. You also can't join if you've had a serious head injury, have other health conditions needing hospitalisation, are pregnant, or are feeling suicidal or violent.

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 16 and 80 years old?
Do you use cannabis weekly or have a recent diagnosis of cannabis use disorder?
Can you provide consent in English or French?
If you have psychosis, are your symptoms stable and have you been on the same medication dose for at least two months?
Do you NOT have other serious drug use issues (besides cannabis, nicotine, caffeine)?
Are you able to have an MRI (no metal in your body, no severe claustrophobia)?
Are you NOT pregnant?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll be assigned by chance to one of two groups: either a group that stops using cannabis for 28 days, or a group that continues using cannabis as usual. Some people in the non-psychosis group who stop using cannabis might receive a small reward for staying abstinent, confirmed by urine tests.

Before you start, you'll have an initial visit where you'll get brain scans (MRI) and complete some memory tasks. You'll also provide a urine sample to check for drugs. Throughout the 28-day period, if you're in the abstinence group, you'll provide urine samples twice a week to confirm you haven't used cannabis. At the end of the 28 days, you'll have another set of brain scans and memory tasks. The total time you'd be involved in the study, including all visits and follow-ups, would be just over one month.

Potential risks and benefits

Participating in this study might help researchers understand more about how cannabis affects the brain and how it recovers if someone stops using it. This could lead to better support for people struggling with cannabis use. However, there are some potential risks. MRI scans can be noisy and feel Claustrophobic for some, and you might feel withdrawal symptoms if you stop using cannabis. There's also a small chance you could feel anxious or stressed during the memory tasks. Remember, your participation is completely voluntary, and you can withdraw from the study at any time without giving a reason, and it won't affect any medical care you receive.

Locations (1)

Douglas Mental Health University Institute
Verified postcode
Montreal, Canada· Recruiting

Common questions

What is psychosis?

Psychosis describes a mental health condition where a person experiences a distorted or changed view of reality, which might include seeing or hearing things that aren't there (hallucinations) or having unusual beliefs (delusions).

What is an MRI scan?

An MRI (Magnetic Resonance Imaging) scan is a type of medical imaging that uses strong magnets and radio waves to create detailed pictures of the inside of your body, including your brain. It does not use X-rays.

What does 'contingency management' mean?

Contingency management in this study means that if you successfully stop using cannabis for 28 days and this is confirmed by tests, you might receive a reward for your efforts.

Will I have to stop using cannabis permanently?

No, if you are in the abstinence group, you will only be asked to stop using cannabis for 28 days for the purpose of the study. After that, your choices about cannabis use are up to you.

Will I know my brain scan results?

The researchers will be analysing the scan results as part of a group to understand general patterns. While individual results typically aren't shared for research studies, you can discuss this with the study team if you have questions.

How to find out more

Charlene Osei-Afrifa

aimh.research@gmail.com (514) 761-6131 Official trial record

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