CannabisADCUFNCT04325958
Age Differences in the Effects of Cannabis on Simulated Driving
A study testing Cannabis in people with Cannabis, run by Centre for Addiction and Mental Health at 1 site in Canada.
Trial summary
Epidemiological studies suggest that the use of cannabis is associated with an increase in the risk of motor vehicle collisions. It is also known that younger users may be at increased risk for motor vehicle collisions. Read more about this study
- Who is it for?
- Ages 19 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Cannabis
- What is being tested?
- Cannabis
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 128 participants
- Where
- 1 siteCanada
- Study dates
- 27 Mar 2024to Mar 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 19-25 or 35-45 years of age;
- Use of smoked cannabis at least once in the past 6 months.
- Use of smoked or vaped cannabis primarily for recreational purposes on up to 1 day per week or on at least 6 days per week in the past 3 months;
- Holds a class G or G2 Ontario driver's licence (or equivalent from another jurisdiction) for at least 12 months;
- Willing to abstain from using alcohol for 24 hours and cannabis for 72 hours prior to Practice and Test Sessions;
- Willing to abstain from all other drugs not prescribed for medical purposes for 48 hours prior to Practice and Test Sessions;
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- Resides within Toronto (study site) or can reside with friends/family in Toronto after a Test Session; this area may be extended to the Greater Toronto area if recruitment challenges arise;
- Participant willing to use appropriate contraception until their participation in the study is completed;
- Provides written and informed consent.
Who cannot join
- Use of cannabis primarily for therapeutic purposes, or equally for therapeutic and recreational purposes;
- Diagnosis of medical condition that contraindicates use of cannabis determined by self-report as judged by the Principal Investigator and a study physician; this includes a history of hypersensitivity to cannabinoids smoke, respiratory disease and/or severe cardiovascular, cerebrovascular, renal or liver disease, and bleeding disorders. Smoking cannabis is not recommended for individuals with respiratory diseases, and they will be excluded;
- Diagnosis of psychiatric condition that contraindicates use of cannabis determined by self-report or SCID-5;
- Participants of childbearing potential: Pregnancy (point-of-care test) or breastfeeding;
- Meets criteria for current or lifetime alcohol or other substance use disorder (DSM-5), except tobacco use disorder and caffeine use disorder;
- Is a regular user of medications that affect brain function (based on self-report); this includes concomitant therapy with sedative-hypnotics or other psychoactive drugs
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- Use of anti-hypertensives;
- First-degree relative diagnosed with schizophrenia or another psychotic disorder.
- Participation in a past driving study at CAMH (to limit practice effects).
- Participation in a clinical study concurrent with their participation in this study.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
Centre for Addiction and Mental Health
Toronto, Ontario, M5S 2S1
Christine Wickens, PhD, 416-535-8501 ext. 34711, christine.wickens@camh.ca
About this study
Official title: The Influence of Age on Driving-related Cannabis Effects: Exploring Cannabis Use Frequency and Related Factors
Epidemiological studies suggest that the use of cannabis is associated with an increase in the risk of motor vehicle collisions. It is also known that younger users may be at increased risk for motor vehicle collisions. Further, the frequency with which cannabis is used may be an important variable in determining the effects of cannabis on driving. The purpose of the present study will be to investigate the effects of cannabis on simulated driving in young as compared to middle-aged drivers. Half of the participants will be occasional users of cannabis and half will be frequent users of cannabis.
Read the detailed description
Epidemiological studies have established that the use of cannabis can increase the risk of a motor vehicle collision. A number of variables can influence the effects of cannabis on driving. For example, frequent users of cannabis have been shown to have different cognitive and physiological responses to cannabis as compared to occasional users. In addition, we know that younger drivers are more likely to be involved in motor vehicle collisions after alcohol use as compared to older users. The contribution of age and experience with cannabis on cannabis-mediated effects on driving have yet to be delineated in laboratory studies. The purpose of the present investigation will be to determine whether cannabis has different effects on driving in young, as compared to middle aged, drivers. Half of each age group will be occasional users of cannabis and the other half will be frequent users.
Eligible participants will attend the laboratory for two test sessions; in one session they will smoke a cannabis cigarette and in the other they smoke a placebo cigarette. Participants will drive a driving simulator before and after smoking the cigarette. Blood for measurement of THC and metabolites will also be collected before smoking the cigarette and at a number of times after smoking. Subjective and cognitive tasks will be completed before and after smoking.
It is hoped that the findings of this study will help to inform public perception and policy into the potential effects of cannabis on driving.
- Conditions
- Cannabis
- Being tested
- Cannabis, Placebos
- Medical subject headings
- Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CannabisDrug
Also called Marijuana
750mg cigarette of plant material
PlacebosDrug
Also called Dummy
750mg cigarette of plant material
| Study group | Role | What they receive |
|---|---|---|
| Age group 19 to 25 | Other | Participants will complete two sessions: one where they drive the simulator before and after smoking a placebo cannabis cigarette (<1% THC), the other where they drive the simulator before and after smoking an active cannabis cigarette (15% ± 5% THC). Receives: Drug: Cannabis; Drug: Placebos |
| Age group 35 to 45 | Other | Participants will complete two sessions: one where they drive the simulator before and after smoking a placebo cannabis cigarette (<1% THC), the other where they drive the simulator before and after smoking an active cannabis cigarette (15% ± 5% THC). Receives: Drug: Cannabis; Drug: Placebos |
What is being measured
The primary outcome is the main question the study is designed to answer.
Standard deviation of lateral position
A measure of 'weaving' when driving the simulator (meters)
Measured: Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure
Secondary outcomes (18)
Mean speed
A measure of the average speed while driving the simulator (km/hr)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Standard deviation of speed
A measure of the variability in speed while driving the simulator (km/hr)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Maximum speed
A measure of the greatest speed obtained while driving the simulator (in km/hr)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Following distance
A measure of the distance between the car being driven and the car in front (meters)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Braking latency
A measure of the time it takes to move the foot from the gas pedal to the brake when a stop sign is encountered (seconds)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Number of collisions
The number of collisions while driving the simulator (total number)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Blood concentration of delta-9-tetrahydrocannabinol (THC)
A measure of the psychoactive component of cannabis in blood (ng/ml)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Blood concentration of carboxy-tetrahydrocannabinol (THC-COOH)
A measure of the inactive metabolite of cannabis in blood (ng/ml)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Blood concentration of 11-hydroxy-tetrahydrocannabinol (11-OH-THC)
A measure of the active metabolite of cannabis in blood (ng/ml)
Measured: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Systolic blood pressure
A vital sign (mmHg)
Measured: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Diastolic blood pressure
A vital sign (mmHg)
Measured: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Heart rate
A vital sign (beats/minute)
Measured: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Visual Analog Scales such as 'I feel this effect', 'I like this drug effect', 'I feel the good effects'
A measure of the subjective effects of cannabis (on a scale of 0 to 100, where is 100 is the strongest level of agreement)
Measured: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Trail Making Test
A measure of the cognitive effects of cannabis (performance speed in seconds)
Measured: Before cannabis exposure and 70 minutes after cannabis
Verbal Free Recall Task
A measure of the cognitive effects of cannabis (number correct)
Measured: Before cannabis exposure and 70 minutes after cannabis
Grooved Pegboard Test
A measure of the cognitive effects of cannabis (performance speed in milliseconds)
Measured: Before cannabis exposure and 70 minutes after cannabis
Simple and Choice Reaction Time Tasks
A measure of the cognitive effects of cannabis (milliseconds)
Measured: Before cannabis exposure and 70 minutes after cannabis
Vienna Risk-Taking Test
A measure of the amount of risk-taking (latency)
Measured: One hour after cannabis exposure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Mar 2020
- Study start27 Mar 2024
- Primary completionMar 2027 (estimated)
- Study completionMar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CannabisStudies of the same condition, open and under way.
- More trials run by Centre for Addiction and Mental HealthThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Model description
- Participants will complete a session with active cannabis and a session with placebo cannabis. Order of sessions is randomized. Participants and Investigator are blinded. Allocation to arms is not randomized. Arms are based on their age.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 128 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Centre for Addiction and Mental Health
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Christine Wickens, PhD, Principal investigator, Centre for Addiction and Mental Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04325958
- Sponsor's protocol ID
- 048/2019
- Acronym
- ADCUF
- Status last verified
- Mar 2026
- First submitted
- 26 Mar 2020
- Last updated
- 23 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Influence of Age on Driving-related Cannabis Effects: Exploring Cannabis Use Frequency and Related Factors
- ClinicalTrials.gov ID
- NCT04325958
- Acronym / sponsor ID
- ADCUF / 048/2019
- Conditions
- Cannabis
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 128 participants (estimated)
- Lead sponsor
- Centre for Addiction and Mental HealthUniversity, hospital or other
- Study start
- 27 Mar 2024 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Mar 2027 (estimated)
- First posted
- 30 Mar 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Epidemiological studies suggest that the use of cannabis is associated with an increase in the risk of motor vehicle collisions. It is also known that younger users may be at increased risk for motor vehicle collisions. Further, the frequency with which cannabis is used may be an important variable in determining the effects of cannabis on driving. The purpose of the present study will be to investigate the effects of cannabis on simulated driving in young as compared to middle-aged drivers. Half of the participants will be occasional users of cannabis and half will be frequent users of cannabis.
Detailed description
Epidemiological studies have established that the use of cannabis can increase the risk of a motor vehicle collision. A number of variables can influence the effects of cannabis on driving. For example, frequent users of cannabis have been shown to have different cognitive and physiological responses to cannabis as compared to occasional users. In addition, we know that younger drivers are more likely to be involved in motor vehicle collisions after alcohol use as compared to older users. The contribution of age and experience with cannabis on cannabis-mediated effects on driving have yet to be delineated in laboratory studies. The purpose of the present investigation will be to determine whether cannabis has different effects on driving in young, as compared to middle aged, drivers. Half of each age group will be occasional users of cannabis and the other half will be frequent users.
Eligible participants will attend the laboratory for two test sessions; in one session they will smoke a cannabis cigarette and in the other they smoke a placebo cigarette. Participants will drive a driving simulator before and after smoking the cigarette. Blood for measurement of THC and metabolites will also be collected before smoking the cigarette and at a number of times after smoking. Subjective and cognitive tasks will be completed before and after smoking.
It is hoped that the findings of this study will help to inform public perception and policy into the potential effects of cannabis on driving.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Participants will complete a session with active cannabis and a session with placebo cannabis. Order of sessions is randomized. Participants and Investigator are blinded. Allocation to arms is not randomized. Arms are based on their age.
| Arm | Type | Receives |
|---|---|---|
| Age group 19 to 25 | Other | Drug: Cannabis, Drug: PlacebosParticipants will complete two sessions: one where they drive the simulator before and after smoking a placebo cannabis cigarette (<1% THC), the other where they drive the simulator before and after smoking an active cannabis cigarette (15% ± 5% THC). |
| Age group 35 to 45 | Other | Drug: Cannabis, Drug: PlacebosParticipants will complete two sessions: one where they drive the simulator before and after smoking a placebo cannabis cigarette (<1% THC), the other where they drive the simulator before and after smoking an active cannabis cigarette (15% ± 5% THC). |
Who may qualify
- Ages
- 19 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (9 listed)
- 19-25 or 35-45 years of age;
- Use of smoked cannabis at least once in the past 6 months.
- Use of smoked or vaped cannabis primarily for recreational purposes on up to 1 day per week or on at least 6 days per week in the past 3 months;
- Holds a class G or G2 Ontario driver's licence (or equivalent from another jurisdiction) for at least 12 months;
- Willing to abstain from using alcohol for 24 hours and cannabis for 72 hours prior to Practice and Test Sessions;
Key exclusion criteria (10 listed)
- Use of cannabis primarily for therapeutic purposes, or equally for therapeutic and recreational purposes;
- Diagnosis of medical condition that contraindicates use of cannabis determined by self-report as judged by the Principal Investigator and a study physician; this includes a history of hypersensitivity to cannabinoids smoke, respiratory disease and/or severe cardiovascular, cerebrovascular, renal or liver disease, and bleeding disorders. Smoking cannabis is not recommended for individuals with respiratory diseases, and they will be excluded;
- Diagnosis of psychiatric condition that contraindicates use of cannabis determined by self-report or SCID-5;
- Participants of childbearing potential: Pregnancy (point-of-care test) or breastfeeding;
- Meets criteria for current or lifetime alcohol or other substance use disorder (DSM-5), except tobacco use disorder and caffeine use disorder;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CannabisAlso: Marijuana750mg cigarette of plant material | Drug | Age group 19 to 25, Age group 35 to 45 |
| PlacebosAlso: Dummy750mg cigarette of plant material | Drug | Age group 19 to 25, Age group 35 to 45 |
Primary outcome
Standard deviation of lateral position
Time frame: Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure
A measure of 'weaving' when driving the simulator (meters)
18 secondary outcomes
Mean speed
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Standard deviation of speed
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Maximum speed
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Following distance
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Braking latency
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Number of collisions
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis exposure
Blood concentration of delta-9-tetrahydrocannabinol (THC)
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Blood concentration of carboxy-tetrahydrocannabinol (THC-COOH)
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Blood concentration of 11-hydroxy-tetrahydrocannabinol (11-OH-THC)
Time frame: Before cannabis exposure and 25 minutes and 2 hours after cannabis
Systolic blood pressure
Time frame: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Diastolic blood pressure
Time frame: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Heart rate
Time frame: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Visual Analog Scales such as 'I feel this effect', 'I like this drug effect', 'I feel the good effects'
Time frame: Before cannabis exposure and 5, 15, 25 minutes and 1, 2, 3, 4 and 5 hours after cannabis
Trail Making Test
Time frame: Before cannabis exposure and 70 minutes after cannabis
Verbal Free Recall Task
Time frame: Before cannabis exposure and 70 minutes after cannabis
Grooved Pegboard Test
Time frame: Before cannabis exposure and 70 minutes after cannabis
Simple and Choice Reaction Time Tasks
Time frame: Before cannabis exposure and 70 minutes after cannabis
Vienna Risk-Taking Test
Time frame: One hour after cannabis exposure
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Mar 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Christine Wickens, PhD principal investigator
Centre for Addiction and Mental Health
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cannabis in people with Cannabis, run by Centre for Addiction and Mental Health at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Christine Wickens, PhD (416 535-8501 ext. 34711, christine.wickens@camh.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Standard deviation of lateral position (time frame: Before cannabis exposure and 30 minutes and 2 hours after cannabis exposure). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Mar 2026.