Cannabis Effects on Driving-related Skills of Young Drivers

September 24, 2018 updated by: Robert Mann, Centre for Addiction and Mental Health

Acute and Residual Effects of Cannabis on Young Drivers' Performance of Driving-related Skills

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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 Type

Interventional

Enrollment (Actual)

99

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5S 2S1
        • Centre for Addiction and Mental Health

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 25 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / 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:
  • marijuana
  • cannabis sativa
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:
  • marijuana
  • cannabis sativa

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Psychomotor Impairment (Driving)
Time Frame: 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.
Approximate: at baseline (30 minutes before smoking), 30 minutes after smoking

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Centre for Addiction and Mental Health

Collaborators

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

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2012

Primary Completion (Actual)

August 1, 2016

Study Completion (Actual)

September 1, 2016

Study Registration Dates

First Submitted

May 3, 2012

First Submitted That Met QC Criteria

May 4, 2012

First Posted (Estimate)

May 7, 2012

Study Record Updates

Last Update Posted (Actual)

February 11, 2019

Last Update Submitted That Met QC Criteria

September 24, 2018

Last Verified

September 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 125/2011

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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