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Cannabis Effects on Driving-related Skills of Young Drivers

Sponsor
Centre for Addiction and Mental Health (Other)
Overall Status
Completed
CT.gov ID
NCT01592409
Collaborator
Canadian Institutes of Health Research (CIHR) (Other), Health Canada (Other)
99
Enrollment
1
Location
2
Arms
50
Duration (Months)
2
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Motor vehicle collisions are the leading cause of death for young people. The investigators have recently found that driving after using cannabis is more common among young Canadian drivers than driving after drinking. While this observation raises concerns, the effects of cannabis on driving-related skills in this age group are not well understood. As well, evidence suggests that residual effects of cannabis on driving-related skills may be observed up to 24 hours later. These residual effects may have important implications for the effects of cannabis use on collision risk, but little evidence on them in available. This study will examine the effects of a single dose of cannabis (marijuana) on driving-related skills immediately following consumption, 24 hours later, and 48 hours later. To date, the residual effect at 48 hours has not been examined. A total of 142 subjects aged 19 to 25 years old will be randomly assigned to smoke either a placebo or active cannabis cigarette (12.5% THC potency). Following an eligibility screening and practice session, participants will attend 3 testing days; drug-administration, 24-hour follow-up and 48-hour follow-up. The effects of cannabis/placebo on performance of driving-related skills using a high-fidelity driving simulator will be assessed on each testing day. The effects of cannabis on mood, cognition, memory and complex reaction time will also be assessed. Identifying factors that affect the collision risks experienced by young drivers is a public health priority. While many young people believe that cannabis does not impair driving, some recent studies suggest that these may be very dangerous beliefs. This study will provide important information on how cannabis may affect the driving skills of young drivers, to inform efforts to understand and address cannabis-related collision in this age group.

Condition or Disease Intervention/Treatment Phase
N/A

Detailed Description

This study will test the prediction that residual effects of an acute dose of cannabis on driving-related skills will be observed in a group of young drivers 48 hours following a single dose of smoked cannabis, and will also examine the effects of an acute dose of cannabis on those skills using driving simulator technology.

Study Objectives

  1. Examine the residual effects of a moderate dose of cannabis (12.5% THC) on driving simulator performance of young drivers. Simulated driving performance, tests of cognition, verbal memory, and mood will be measured concurrently with levels of cannabinoids in biological fluids at approximately 24 and 48 hours following acute drug exposure in male and female drivers aged 19 to 25. We will test the hypothesis that performance on a high-fidelity driving simulator task will be significantly impaired approximately 24 hours following a dose of cannabis in comparison to a placebo condition.

  2. Examine the acute effects of a moderate dose of cannabis (12.5% THC) on driving simulator performance of young drivers. Simulated driving performance, tests of cognition, verbal memory, and mood will be measured concurrently with levels of cannabinoids in biological fluids before and after drug administration. Cannabinoid levels in biological fluids will be measured over a 6 hour period following drug exposure. We will examine the relationship of cannabinoid levels to performance measures in this time frame.

  3. Explore the effects of driving history, driving attitudes, and individual difference measures (e.g., demographics, drug and alcohol use, etc.) on the acute and residual effects of cannabis on driving simulator performance of young drivers. Exploratory analyses will be undertaken to determine if the acute and residual effects of cannabis on the driving simulator task are influenced by these measures.

  4. Determine if a relationship exists between genetics and THC response. As an ancillary aim, blood samples may be collected for future research to determine if a relationship exists between genetic polymorphisms and pharmacokinetic and pharmacodynamic responses to cannabis.

Study Design and Duration

The study is a double-blind, placebo-controlled mixed-design study, including a randomized between-subjects comparison of the effects of smoked cannabis and both between- and within-subjects examination of its residual effects at 24 and 48 hours following one-time drug administration. Although a placebo condition is part of the study, this is not a treatment study.

Initial contact with potential subjects will be made via telephone, and study personnel will conduct a telephone screen for eligibility. Upon eligibility confirmation by telephone, participants will be asked to attend CAMH for an eligibility assessment. The study will consist of 5 sessions for each subject (an eligibility assessment, a practice day, and three subsequent testing days). Participants will be asked not to use cannabis for 48 hours prior to attending the practice day (Session 2). Although Session 1 can be completed at any time prior to the remaining study sessions, Sessions 2 - 5 must be performed on consecutive days.

In certain instances, the Qualified Investigator may ask a participant to return for re-screening, e.g. repeat of urine test or other assessments performed for eligibility assessment. Also, in case of unforeseen delays in scheduling study participation, the Qualified Investigator will determine if there is a need to ask a participant to repeat some assessments, e.g., physical examination.

Study Design

Study Type:
Interventional
Actual Enrollment :
99 participants
Allocation:
Randomized
Intervention Model:
Parallel Assignment
Masking:
Double (Participant, Investigator)
Primary Purpose:
Basic Science
Official Title:
Acute and Residual Effects of Cannabis on Young Drivers' Performance of Driving-related Skills
Study Start Date :
Jul 1, 2012
Actual Primary Completion Date :
Aug 1, 2016
Actual Study Completion Date :
Sep 1, 2016

Arms and Interventions

Arm Intervention/Treatment
Active Comparator: Active cannabis

In this condition, participants will receive a cigarette containing 12.5% active THC.

Drug: delta-9-tetrahydrocannabinol
A single cannabis cigarette (potency 12.5% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose.
Other Names:
  • cannabis sativa
  • marijuana

    		•
    Placebo Comparator: Placebo

    In this condition, participants will receive a cannabis cigarette where the active THC has been removed (contains 0% THC).

    Drug: Placebo
    A single placebo cannabis cigarette (0% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study).
    Other Names:
  • cannabis sativa
  • marijuana

    		•

    Outcome Measures

    Primary Outcome Measures

    1. Psychomotor Impairment (Driving) [Approximate: at baseline (30 minutes before smoking), 30 minutes after smoking]

      The driving simulator will objectively measure driving behaviour during a number of pre-programmed driving scenarios. Zone/ Hazard performance measure: Mean Speed.

    Eligibility Criteria

    Criteria

    Ages Eligible for Study:
    19 Years to 25 Years
    Sexes Eligible for Study:
    All
    Accepts Healthy Volunteers:
    Yes
    Inclusion Criteria:

    • Males and females aged 19 to 25

    • Regular cannabis users (between one and four times per week)

    • Held a valid class G or G2 Ontario driver's license (or equivalent from another jurisdiction) for at least 12 months.

    • Willing to abstain from cannabis use for the duration of the study, and for 48 hours prior to Session 2.

    • Provides written and informed consent

    • Urine toxicology result positive for THC (indicating recent use of cannabis).

    Exclusion Criteria:

    • Positive breathalyzer results for alcohol on any given study day.

    • Is a regular user of medications that affect brain function (i.e., antidepressants, benzodiazepines, stimulants).

    • Diagnosis of severe medical or psychiatric conditions.

    • A first degree relative diagnosed with schizophrenia.

    • Meets criteria for current or lifetime Substance Use Disorders (DSM-IV) with the exception of nicotine.

    • Meets criteria for Cannabis Dependence (DSM-IV).

    • Is pregnant, is trying to become pregnant, or is currently breastfeeding.

    Ongoing Exclusion Criteria:

    • Upon eligibility assessment, toxicology results indicate that the participant has not used cannabis recently.

    • Any toxicology screen after Session 2 - Practice Day indicating a psychoactive substance has been used other than cannabis.

    Contacts and Locations

    Locations

    Site City State Country Postal Code
    1 Centre for Addiction and Mental Health Toronto Ontario Canada M5S 2S1

    Sponsors and Collaborators

    • Centre for Addiction and Mental Health
    • Canadian Institutes of Health Research (CIHR)
    • Health Canada

    Investigators

    • Principal Investigator: Robert Mann, Ph.D., Centre for Addiction and Mental Health
    • Principal Investigator: Bernard Le Foll, M.D., Ph.D., Centre for Addiction and Mental Health

    Study Documents (Full-Text)

    None provided.

    More Information

    Additional Information:

    Publications

    Responsible Party:
    Robert Mann, Principal Investigator, Centre for Addiction and Mental Health
    ClinicalTrials.gov Identifier:
    NCT01592409
    Other Study ID Numbers:
    • 125/2011
    First Posted:
    May 7, 2012
    Last Update Posted:
    Feb 11, 2019
    Last Verified:
    Sep 1, 2018
    Keywords provided by Robert Mann, Principal Investigator, Centre for Addiction and Mental Health
    cannabis impaired driving
    driving simulation
    acute psychopharmacologic effects of cannabis
    residual effects of cannabis
    young drivers
    Additional relevant MeSH terms:
    Psychomotor Disorders
    Marijuana Abuse
    Dronabinol

    Study Results

    Participant Flow

    Recruitment Details Recruitment was by media ads and research postings in Toronto.
    Pre-assignment Detail Screened over the telephone n=1024. Assessed for eligibility (n=178). Excluded: Not meeting inclusion criteria n=45, Declined to participate or lost interest n=32, Did not receive IP (did not return after practice session) n=2. Pilots (received active cannabis, not randomized) n=5. Randomized n=94.
    Arm/Group Title Active Cannabis Placebo
    Arm/Group Description In this condition, participants will receive a cigarette containing 12.5% active THC. delta-9-tetrahydrocannabinol: A single cannabis cigarette (potency 12.5% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose. In this condition, participants will receive a cannabis cigarette where the active THC has been removed (contains 0% THC). Placebo: A single placebo cannabis cigarette (0% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study).
    Period Title: Overall Study
    STARTED 67 32
    COMPLETED 67 31
    NOT COMPLETED 0 1

    Baseline Characteristics

    Arm/Group Title Active Cannabis Placebo Total
    Arm/Group Description In this condition, participants will receive a cigarette containing 12.5% active THC. delta-9-tetrahydrocannabinol: A single cannabis cigarette (potency 12.5% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose. In this condition, participants will receive a cannabis cigarette where the active THC has been removed (contains 0% THC). Placebo: A single placebo cannabis cigarette (0% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study). Total of all reporting groups
    Overall Participants 67 31 98
    Age (years) [Mean (Standard Deviation) ]
    Mean (Standard Deviation) [years]
    22.22
    (1.88)
    21.97
    (2.24)
    22.14
    (1.995)
    Sex: Female, Male (Count of Participants)
    Female
    19
    28.4%
    9
    29%
    28
    28.6%
    Male
    48
    71.6%
    22
    71%
    70
    71.4%
    Region of Enrollment (participants) [Number]
    Canada
    67
    100%
    31
    100%
    98
    100%

    Outcome Measures

    1. Primary Outcome
    Title Psychomotor Impairment (Driving)
    Description The driving simulator will objectively measure driving behaviour during a number of pre-programmed driving scenarios. Zone/ Hazard performance measure: Mean Speed.
    Time Frame Approximate: at baseline (30 minutes before smoking), 30 minutes after smoking

    Outcome Measure Data

    Analysis Population Description
    Zone/Hazard performance measure: Mean Speed (Change from drug-free baseline to 30 minutes after smoking cannabis in kilometres per hour (kph)
    Arm/Group Title Active Cannabis Placebo
    Arm/Group Description In this condition, participants will receive a cigarette containing 12.5% active THC. delta-9-tetrahydrocannabinol: A single cannabis cigarette (potency 12.5% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose. In this condition, participants will receive a cannabis cigarette where the active THC has been removed (contains 0% THC). Placebo: A single placebo cannabis cigarette (0% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study).
    Measure Participants 67 31
    Mean (Standard Deviation) [change in kph]
    3.38
    (9.75)
    -1.54
    (7.36)

    Adverse Events

    Time Frame Collected from session 1 (eligibility assessment) to session 2 (practice) (approx. 3 months); from session 2 to 3 (approx. 24 hours), from session 3 to 4 (approx. 24 hours), session 4 to session 5 (approx. 24 hours).
    Adverse Event Reporting Description
    Arm/Group Title Active Cannabis Placebo
    Arm/Group Description In this condition, participants will receive a cigarette containing 12.5% active THC. delta-9-tetrahydrocannabinol: A single cannabis cigarette (potency 12.5% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose. In this condition, participants will receive a cannabis cigarette where the active THC has been removed (contains 0% THC). Placebo: A single placebo cannabis cigarette (0% THC) will be given to participants to smoke over a 10 minute period, ad lib. If the cigarette is not smoked in its entirety, the remainder will be weighed to estimate dose (as this is a double-blind study).
    All Cause Mortality
    Active Cannabis Placebo
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 0/67 (0%) 0/32 (0%)
    Serious Adverse Events
    Active Cannabis Placebo
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 0/67 (0%) 0/32 (0%)
    Other (Not Including Serious) Adverse Events
    Active Cannabis Placebo
    Affected / at Risk (%) # Events Affected / at Risk (%) # Events
    Total 38/67 (56.7%) 15/32 (46.9%)
    Cardiac disorders
    rapid heartbeat 2/67 (3%) 0/32 (0%)
    Ear and labyrinth disorders
    earache 1/67 (1.5%) 0/32 (0%)
    simulation sickness 1/67 (1.5%) 2/32 (6.3%)
    Gastrointestinal disorders
    food poisoning 1/67 (1.5%) 0/32 (0%)
    nausea 1/67 (1.5%) 1/32 (3.1%)
    stomach/abdominal discomfort 2/67 (3%) 0/32 (0%)
    vomiting 0/67 (0%) 1/32 (3.1%)
    abdominal pain 3/67 (4.5%) 0/32 (0%)
    General disorders
    dizziness/faintness 5/67 (7.5%) 2/32 (6.3%)
    diaphoresis 1/67 (1.5%) 0/32 (0%)
    difficulty falling asleep 1/67 (1.5%) 0/32 (0%)
    headache 10/67 (14.9%) 2/32 (6.3%)
    insomnia 6/67 (9%) 0/32 (0%)
    nasal infection 1/67 (1.5%) 0/32 (0%)
    somnolence 4/67 (6%) 1/32 (3.1%)
    tiredness/fatigue 5/67 (7.5%) 3/32 (9.4%)
    Immune system disorders
    allergies 0/67 (0%) 1/32 (3.1%)
    Metabolism and nutrition disorders
    increased appetite 0/67 (0%) 1/32 (3.1%)
    Musculoskeletal and connective tissue disorders
    injury 0/67 (0%) 2/32 (6.3%)
    muscle/bone/joint pain 3/67 (4.5%) 2/32 (6.3%)
    Psychiatric disorders
    anxiety/nervousness 1/67 (1.5%) 2/32 (6.3%)
    Reproductive system and breast disorders
    genital discomfort 1/67 (1.5%) 1/32 (3.1%)
    Respiratory, thoracic and mediastinal disorders
    common cold 3/67 (4.5%) 1/32 (3.1%)
    sore throat 0/67 (0%) 1/32 (3.1%)
    Skin and subcutaneous tissue disorders
    bruising 1/67 (1.5%) 1/32 (3.1%)
    itching 1/67 (1.5%) 0/32 (0%)
    rash 4/67 (6%) 0/32 (0%)
    Vascular disorders
    low blood pressure 4/67 (6%) 1/32 (3.1%)
    loss of consciousness 2/67 (3%) 0/32 (0%)

    Limitations/Caveats

    The study examined simulated driving behavior of young regular cannabis users (1 to 4 times per week) and the generalization to new or frequent cannabis users, older drivers, and to real-world driving is unclear.

    More Information

    Certain Agreements

    All Principal Investigators ARE employed by the organization sponsoring the study.

    There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

    Results Point of Contact

    Name/Title Dr. Robert Mann, Senior Scientist
    Organization Centre for Addiction and Mental Health
    Phone 416-535-8501 ext 34496
    Email robert.mann@camh.ca
    Responsible Party:
    Robert Mann, Principal Investigator, Centre for Addiction and Mental Health
    ClinicalTrials.gov Identifier:
    NCT01592409
    Other Study ID Numbers:
    • 125/2011
    First Posted:
    May 7, 2012
    Last Update Posted:
    Feb 11, 2019
    Last Verified:
    Sep 1, 2018