RecruitingNAINTERVENTIONAL

Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes

This study explores the effects of cannabis and tobacco, both separately and when used together, on driving ability, thinking skills, and physical responses. Many people use cannabis and tobacco at the same time, but we don't fully understand why or what the combined effects are. Some early ideas suggest tobacco might lessen the mind-altering effects of cannabis or even make using cannabis more enjoyable. However, this isn't certain. This research aims to clear up these questions using a driving simulator. It will also check to see if tobacco changes how much THC (the main active chemical in cannabis) gets into the blood.

At a glance

Status

Recruiting

Phase

Sponsor

Centre for Addiction and Mental Health

Enrolment target

Start

07 Oct 2024

Estimated completion

01 Mar 2027

Driving Under the Influence

What is this study about?

This research is looking into how cannabis and tobacco affect people, especially when they're used together. Many people who use cannabis also use tobacco at the same time, but we don't really know why this is such a common habit. We also don't fully understand what happens to your body and mind when you mix them.

Previous small studies have hinted that tobacco might actually reduce some of the confusing effects of cannabis on your thinking, and it might even make the experience of using cannabis more pleasant. However, these findings aren't yet strong enough to be sure. This study hopes to answer these important questions, especially about how these substances affect your driving and other day-to-day activities.

To do this, volunteers will try cannabis, tobacco, a mix of both, or a dummy substance called a placebo. Their driving will be tested safely in a special simulator, and their thinking skills will be assessed. Researchers will also look at how these substances affect their body and how much 'THC' (the main active ingredient in cannabis) is in their blood. This is one of the first studies to properly investigate why people use cannabis and tobacco together and what the combined effects truly are.

Key takeaways

This study investigates the combined effects of cannabis and tobacco.
It uses a safe driving simulator to test impacts on driving skills.
Participants will try cannabis, tobacco, both, or a dummy substance.
The study also examines how these substances affect thinking and the amount of THC in your blood.
Findings could help us understand why people mix cannabis and tobacco.
It's one of the first lab studies to look at these combined effects in detail.

Who may be eligible?

This study is looking for healthy adults between 19 and 45 years old. You need to be someone who uses cannabis regularly, but not too often – specifically, you typically use it at least once a month but no more than four times a week. You should also have experience smoking cannabis and have used nicotine products (like cigarettes or vapes) in the past year.

It's important that you have a valid G2 or full G driving licence that you've held for at least a year. You also need to have some history of using cannabis and tobacco together. Before each study visit, you'll need to agree not to drink alcohol or use other drugs for 48 hours, and not use cannabis for 72 hours or smoke tobacco for 12 hours. You'll also need a healthy heart and normal blood pressure.

There are some reasons why you might not be able to join. For example, if you're taking certain mental health medications, or if you have a history of serious addiction to alcohol or other drugs (including cannabis or nicotine). People with specific medical conditions, like serious lung problems, heart issues, or a family history of schizophrenia, would also not be able 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 between 19 and 45 years old?
Do you use cannabis regularly (1-4 times a week) and have you used nicotine in the past year?
Do you have a G2 or full G driving licence for at least a year?
Are you generally healthy with normal heart rate and blood pressure?
Are you willing to avoid cannabis for 72 hours and tobacco for 12 hours before each test?
Do you have experience using cannabis and tobacco together?

Answer every question to see your result.

What does participation involve?

If you join this study, you'll visit the lab four times. During each visit, you'll be given one of four things to smoke: cannabis, tobacco, a mix of cannabis and tobacco, or a placebo (which looks and tastes like the real thing but has no active ingredients). This is done in a careful order that's different for each person.

Before and after smoking, you'll use a special driving simulator to test your driving skills safely. You'll also complete tests to check your thinking and memory. Researchers will take blood samples to measure the levels of THC (the active chemical in cannabis) in your system at different times. You will also fill out questionnaires about how you feel after smoking. Each visit will involve these measurements at several points after you've smoked. The total time for participating in the study will involve these four separate lab visits.

Potential risks and benefits

Taking part in this study may help us understand more about how cannabis and tobacco affect people, which could lead to better public health advice in the future. As with any study involving substances, there are potential risks, such as experiencing the typical effects of cannabis or tobacco, which can include changes in heart rate, thinking, and mood. We've taken great care to ensure your safety by checking your health carefully before you start and by using a driving simulator rather than actual driving. You are free to stop participating in the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Centre for Addiction and Mental Health
Verified postcode
Toronto, Canada· Recruiting

Common questions

What is a 'placebo'?

A placebo is a 'dummy' substance that looks like the real thing but contains no active ingredients. It helps researchers compare the actual effects of a substance to a baseline.

Why do I need to abstain from alcohol and drugs before the sessions?

This is to make sure that only the cannabis and/or tobacco being studied are affecting you, so the study results are clear and accurate.

Will I be driving a real car?

No, you will be using a state-of-the-art driving simulator. This allows researchers to safely measure driving ability without any risk on actual roads.

Why do I need to have used both cannabis and tobacco before?

The study needs people who are familiar with both substances and their combined effects to understand their experiences and reactions.

What is 'THC'?

THC is the main chemical in cannabis that causes its mind-altering effects. Researchers will measure its levels in your blood.

How to find out more

Patricia Di Ciano

patricia.diciano@camh.ca 416-535-8501 Official trial record

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