Effects of THC and Alcohol on Driving Performance

April 20, 2022 updated by: Lakehead University

Determining the Combined Effects of THC and Alcohol on Driving Performance

Low blood concentrations of THC and alcohol appear to have a minimal effect on driving performance.However, there is a gap in the literature about the combined effects of THC and alcohol. There is little empirical evidence to determine whether the combination of THC and alcohol could be additive or multiplicative. This issue is particularly important when dealing with concentrations that are just below legal thresholds - it is important to identify if someone who may have consumed cannabis and alcohol, in quantities that do not exceed legal thresholds, may nonetheless be impaired to drive. Answering this question requires more research on the combined effects of THC and alcohol under tightly controlled experimental conditions. Hence, the purpose of this study is to determine the additive (or multiplicative) effect of standardized low doses of cannabis, in combination with low-doses of alcohol, on a number of outcome measures related to driving. The investigators will focus specifically on the effect of low blood concentrations of THC (0, 125, and 250 µg/kg) alone and in combination with low blood concentrations of alcohol (BAC 0%, .025%, and .049%). They shall determine the combined effect of THC and alcohol on physiological, cognitive, subjective measures of impairment, and simulated driving. This study will focus on younger adults because they have higher impaired driving rates than other age groups. As a secondary aim of the study, the investigators will examine whether previous driving and drug use history are correlated with driving decisions during the simulated drive and subjective measures. This study will contribute to the evidence base informing legislation, policy making, and law enforcement. This study is particularly timely given upcoming changes in legislation about cannabis, and because the combination of THC and alcohol, even below legal thresholds, may lead to impaired driving and crashes.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

19 years to 25 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • BMI >18 and <30
  • valid G2 or G Ontario driver's license
  • live on-campus or within 15 minutes drive of campus
  • speak fluent English

Exclusion Criteria:

  • history of cardiovascular or psychiatric disorders
  • current use of psychoactive medication
  • current drug or alcohol abuse problem
  • positive drug screen
  • BAC level > .000%

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: FACTORIAL
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
PLACEBO_COMPARATOR: THC 0 + BAC 0
Participants will receive 0mg of THC in combination with blood alcohol concentrations of .000%.
Drug: THC 0
THC dose = 0mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC 0
Blood alcohol concentration = .000%
EXPERIMENTAL: THC 5 + BAC 0
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .000%.
Other: BAC 0
Blood alcohol concentration = .000%
Drug: THC 5
THC dose = 5mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
EXPERIMENTAL: THC 10 + BAC 0
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .000%.
Other: BAC 0
Blood alcohol concentration = .000%
Drug: THC 10
THC dose = 10mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
EXPERIMENTAL: THC 5 + BAC .025
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .025%.
Drug: THC 5
THC dose = 5mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .025
Blood alcohol concentration = .025%
EXPERIMENTAL: THC 10 + BAC .025
Participants will receive 125 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Drug: THC 5
THC dose = 5mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .025
Blood alcohol concentration = .025%
EXPERIMENTAL: THC 0 + BAC .049
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.
Drug: THC 0
THC dose = 0mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Drug: THC 10
THC dose = 10mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .025
Blood alcohol concentration = .025%
Other: BAC .049
Blood alcohol concentration = .049%
EXPERIMENTAL: THC 5 + BAC .049
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .049%.
Drug: THC 5
THC dose = 5mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .049
Blood alcohol concentration = .049%
EXPERIMENTAL: THC 10 + BAC .049
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .049%.
Drug: THC 5
THC dose = 5mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .049
Blood alcohol concentration = .049%
EXPERIMENTAL: THC 0 + BAC .025
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Drug: THC 0
THC dose = 0mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Drug: THC 10
THC dose = 10mg
Other Names:
  • Cannabis
  • Dronabinol
  • Tetrahydrocannabinol
Other: BAC .025
Blood alcohol concentration = .025%
Other: BAC .049
Blood alcohol concentration = .049%

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Demerit Points on Simulated Road Test
Time Frame: @2.5 hours
Demerit points incurred for driving errors during a simulated a G2 exit exam (the final step in Ontario's graduated licensing framework) on a STISIM Drive 3-screen driving simulator; demerit points will be assigned in real-time by a member of the research team based on the Ontario Ministry of Transportation scoring scheme
@2.5 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Standard Deviation of Lane Position in Meters (STISIM Drive-Recorded Variable)
Time Frame: @2.5 hours
Recorded by the STISIM simulator during the simulation
@2.5 hours
Mean and Standard Deviation of Velocity in Meters/Second (STISIM Drive-Recorded Variable)
Time Frame: @2.5 hours
Recorded by the STISIM simulator during the simulation
@2.5 hours
Mean and Standard Deviation of Acceleration in Meters/Second (STISIM Drive-Recorded Variable)
Time Frame: @2.5 hours
Recorded by the STISIM simulator during the simulation
@2.5 hours
Blood Pressure (Systolic/Diastolic mmHg)
Time Frame: @25 minutes and 2 hours
Systolic & diastolic blood pressure via automated blood pressure cuff
@25 minutes and 2 hours
Heart Rate (BPM) & Heart Rate Variability via ECG
Time Frame: Hour 0-3.5
Continuous heart rate in beats per minute via 3-lead electrocardiography recording; will allow for calculation of heart rate variability)
Hour 0-3.5
Electrical Brain Activity via EEG
Time Frame: Hour 0-3.5
Continuous brain activity via electroencephalography recording
Hour 0-3.5
Median Response Time and Efficiency in Alerting, Orienting & Executive Attention as Measured by the Attention Network Test (in milliseconds)
Time Frame: @25 minutes and 2 hours
A computerized test to measure participants' performance in three separate components of attention: alerting, orienting, and executive attention
@25 minutes and 2 hours
Perceptual Motor Speed & Efficiency as Measured by Time (in seconds) to Complete Trail Making Tests A&B
Time Frame: @25 minutes and 2 hours
A pen and paper test to measure perceptual motor speed and efficiency
@25 minutes and 2 hours
Visual Analogue Scale of Perceived Effects
Time Frame: @25 minutes and 2 hours
Ratings of participants' current perceptions of mood and bodily sensations (22 items including anxiety, alertness, dizziness, dry mouth) driving (3 items related to current willingness to drive), and subjective impairment (at time 2 only; 6 items related to strength of effects, perceived performance on tests); all items measures from not at all>extremely or absent>severe on a 100 mm line
@25 minutes and 2 hours

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Lakehead University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michel Bédard, PhD, Lakehead University

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 (ANTICIPATED)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2021

Primary Completion (ANTICIPATED)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2021

Study Completion (ANTICIPATED)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 18, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 1, 2018

First Posted (ACTUAL)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 14, 2018

Study Record Updates

Last Update Posted (ACTUAL)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 25, 2022

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 20, 2022

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2018502

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

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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