Driving ImpairedPhase 2NCT03656029
Dose-response of Cannabis and Driving
A Phase 2 study testing Cannabis in people with Driving Impaired and Cognitive Impairment, run by Centre for Addiction and Mental Health at 1 site in Canada.
Trial summary
Epidemiological studies have established a link between collisions while driving and cannabis use. With the changing legal landscape around cannabis, there is much interest in determining per se limits of cannabis while driving. Read more about this study
- Who is it for?
- Ages 19 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Driving Impaired, Cognitive Impairment, Abuse Cannabis
- What is being tested?
- Cannabis
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 36 participants
- Where
- 1 siteCanada
- Study dates
- 4 Jun 2021to 14 Jun 2022
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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
- Near daily use of cannabis (1-5 days/week) confirmed by self-report and urine screening
- Has held a class G2 or G licence (or equivalent from another jurisdiction) for at least 12 months
- Willing to abstain from using cannabis for 72 hours prior to each practice or test session
- Willing to abstain from alcohol for 48 hours prior to each session, and to abstain from all other drugs not medically required for the duration of the study (beginning 48 hours prior to the practice session)
- Provides written and informed consent
Who cannot join
- Diagnosis of severe medical or psychiatric condition
- Meets criteria for current or lifetime alcohol or other substance use disorder, except tobacco use disorder and caffeine use disorder
- Regular user of medication that may affect cognitive functioning and/or driver performance
- Family history of schizophrenia or other psychotic disorder
- Pregnant, looking to become pregnant, or breastfeeding
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Dose-dependent Effects of Smoked Cannabis on Simulated Driving Performance
Epidemiological studies have established a link between collisions while driving and cannabis use. With the changing legal landscape around cannabis, there is much interest in determining per se limits of cannabis while driving. The present study will evaluate driving on a driving simulator after smoking placebo or cannabis with 3 different levels of THC. THC is the active component in cannabis and blood, urine and oral fluid levels of THC will be correlated with driving impairment.
Read the detailed description
Participants will attend the laboratory for 4 separate sessions, separated by about a week. In each session, participants will receive one of 3 doses of smoked cannabis or a placebo. Participants will not know which dose they are receiving. Participants will complete questionnaires, do cognitive tests and drive on a driving simulator before and after smoking the cannabis or placebo cigarette. Blood, urine and oral fluid will be collected throughout the 7-8 hour session to determine levels of THC and its metabolites. These values will be correlated with measures of driving impairment.
- Conditions
- Driving Impaired, Cognitive Impairment, Abuse Cannabis
- Being tested
- Cannabis, Placebo
- Medical subject headings
- Cognitive Dysfunction, Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CannabisDrug
Participants will smoke as much of the cigarette as they wish
PlaceboDrug
Participants will smoke a placebo cigarette
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Participants will smoke a single smoked placebo (<0.1% THC) cannabis cigarette Receives: Drug: Placebo |
| low dose | Active comparator | Participants will smoke a single low dose (6.25% THC) of smoked cannabis cigarette Receives: Drug: Cannabis |
| middle dose | Active comparator | Participants will smoke a single intermediate dose (12.5% THC) of smoked cannabis cigarette Receives: Drug: Cannabis |
| high dose | Active comparator | Participants will smoke a single high dose (22% THC) of smoked cannabis cigarette Receives: Drug: Cannabis |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean speed
Speed of driving the simulator
Measured: Change in speed of driving between the time before smoking the cigarette and either 30 or 90 minutes after smoking the cigarette
Secondary outcomes (11)
Standard deviation of lateral position
Driving measures
Measured: Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking
reaction time
Driving measures
Measured: Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking
Blood concentrations of THC and metabolites
Blood will be taken to determine how much THC entered the blood
Measured: Change from before smoking cigarette to various time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Oral fluid concentrations of THC and metabolites
Participants will provide oral fluid to determine how much THC is in the oral fluid
Measured: Change from levels before smoking to 4 time points after smoking: 30 minutes, 90 minutes, 2 hours and 6 hours
Systolic and Diastolic Blood pressure
Vital signs
Measured: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Heart rate
Vital signs
Measured: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Respirations
Vital signs
Measured: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Temperature
Vital signs
Measured: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Visual Analog Scales
Tests designed to assess the degree of subjective effects of the drug. The questions will be scored on a scale from 0 to 100 and will consist of: 'I like this drug effect', 'this feels like cannabis', 'I feel this effect', 'I feel this high', 'I feel the good effects', 'I feel the bad effects', 'I feel the rush'
Measured: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Verbal free recall test
Test of memory: Participants will be asked to recall words that are read from a list
Measured: Change from pre-smoking levels to those observed 60 minutes after smoking
Useful field of view
A computer test for visual processing speed, selective and divided attention
Measured: Change from pre-smoking levels to those observed 60 minutes after smoking
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Sep 2018
- Study start4 Jun 2021
- Primary completion14 Jun 2022
- Study completion14 Jun 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Driving ImpairedStudies 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 2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This will be a within-subjects, counterbalanced, placebo-controlled study of placebo or 3 doses of cannabis
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- Centre for Addiction and Mental Health
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Bruna Brands, PhD, Principal investigator, Centre for Addiction and Mental Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03656029
- Sponsor's protocol ID
- 007-2018
- Status last verified
- Oct 2022
- First submitted
- 8 Aug 2018
- Last updated
- 7 Oct 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Brands B, Zaweel A, Wright M, Di Ciano P, Wickens CM, Matheson J, Fares A, Hasan OSM, Sanches M, Sproule B, Huestis MA, Brown TL, Le Foll B. Potency-related effects of smoked cannabis on simulated driving performance: a randomized, controlled crossover trial. Sci Rep. 2026 Mar 10;16(1):12961. doi: 10.1038/s41598-026-43045-2.
PubMed 41807521
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dose-dependent Effects of Smoked Cannabis on Simulated Driving Performance
- ClinicalTrials.gov ID
- NCT03656029
- Acronym / sponsor ID
- 007-2018
- Conditions
- Driving Impaired, Cognitive Impairment, Abuse Cannabis
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- Centre for Addiction and Mental HealthUniversity, hospital or other
- Study start
- 4 Jun 2021 (actual)
- Primary completion
- 14 Jun 2022 (actual)
- Study completion
- 14 Jun 2022 (actual)
- First posted
- 4 Sep 2018 (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 have established a link between collisions while driving and cannabis use. With the changing legal landscape around cannabis, there is much interest in determining per se limits of cannabis while driving. The present study will evaluate driving on a driving simulator after smoking placebo or cannabis with 3 different levels of THC. THC is the active component in cannabis and blood, urine and oral fluid levels of THC will be correlated with driving impairment.
Detailed description
Participants will attend the laboratory for 4 separate sessions, separated by about a week. In each session, participants will receive one of 3 doses of smoked cannabis or a placebo. Participants will not know which dose they are receiving. Participants will complete questionnaires, do cognitive tests and drive on a driving simulator before and after smoking the cannabis or placebo cigarette. Blood, urine and oral fluid will be collected throughout the 7-8 hour session to determine levels of THC and its metabolites. These values will be correlated with measures of driving impairment.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
- Model description
- This will be a within-subjects, counterbalanced, placebo-controlled study of placebo or 3 doses of cannabis
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Drug: PlaceboParticipants will smoke a single smoked placebo (<0.1% THC) cannabis cigarette |
| low dose | Active comparator | Drug: CannabisParticipants will smoke a single low dose (6.25% THC) of smoked cannabis cigarette |
| middle dose | Active comparator | Drug: CannabisParticipants will smoke a single intermediate dose (12.5% THC) of smoked cannabis cigarette |
| high dose | Active comparator | Drug: CannabisParticipants will smoke a single high dose (22% THC) of smoked cannabis cigarette |
Who may qualify
- Ages
- 19 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Near daily use of cannabis (1-5 days/week) confirmed by self-report and urine screening
- Has held a class G2 or G licence (or equivalent from another jurisdiction) for at least 12 months
- Willing to abstain from using cannabis for 72 hours prior to each practice or test session
- Willing to abstain from alcohol for 48 hours prior to each session, and to abstain from all other drugs not medically required for the duration of the study (beginning 48 hours prior to the practice session)
- Provides written and informed consent
Key exclusion criteria (5 listed)
- Diagnosis of severe medical or psychiatric condition
- Meets criteria for current or lifetime alcohol or other substance use disorder, except tobacco use disorder and caffeine use disorder
- Regular user of medication that may affect cognitive functioning and/or driver performance
- Family history of schizophrenia or other psychotic disorder
- Pregnant, looking to become pregnant, or breastfeeding
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 |
|---|---|---|
| CannabisParticipants will smoke as much of the cigarette as they wish | Drug | high dose, low dose, middle dose |
| PlaceboParticipants will smoke a placebo cigarette | Drug | Placebo |
Primary outcome
Mean speed
Time frame: Change in speed of driving between the time before smoking the cigarette and either 30 or 90 minutes after smoking the cigarette
Speed of driving the simulator
11 secondary outcomes
Standard deviation of lateral position
Time frame: Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking
reaction time
Time frame: Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking
Blood concentrations of THC and metabolites
Time frame: Change from before smoking cigarette to various time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Oral fluid concentrations of THC and metabolites
Time frame: Change from levels before smoking to 4 time points after smoking: 30 minutes, 90 minutes, 2 hours and 6 hours
Systolic and Diastolic Blood pressure
Time frame: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Heart rate
Time frame: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Respirations
Time frame: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Temperature
Time frame: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Visual Analog Scales
Time frame: Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours
Verbal free recall test
Time frame: Change from pre-smoking levels to those observed 60 minutes after smoking
Useful field of view
Time frame: Change from pre-smoking levels to those observed 60 minutes after smoking
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2022.
- Derived from this study: PubMed 41807521Brands B, Zaweel A, Wright M, Di Ciano P, Wickens CM, Matheson J, Fares A, Hasan OSM, Sanches M, Sproule B, Huestis MA, Brown TL, Le Foll B. Potency-related effects of smoked cannabis on simulated driving performance: a randomized, controlled crossover trial. Sci Rep. 2026 Mar 10;16(1):12961. doi: 10.1038/s41598-026-43045-2.
- 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. This study is not recruiting at the moment.
Bruna Brands, 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 Phase 2 study testing Cannabis in people with Driving Impaired and Cognitive Impairment, 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 5 inclusion and 5 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: finished, as of the sponsor's last update on 7 Oct 2022. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean speed (time frame: Change in speed of driving between the time before smoking the cigarette and either 30 or 90 minutes after smoking the cigarette). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03656029, which also lists 1 linked publication.
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 7 Oct 2022.