Determining the Combined Effects of THC and Alcohol on Driving Performance
Trial Snapshot
- Phase
- Phase 4
- Status
- Withdrawn
- Sponsor
- Lakehead University
- Primary Endpoint
- Demerit Points on Simulated Road Test
Study Overview
Brief Summary
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 Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Factorial
- Primary Purpose
- Basic Science
- Masking
- Triple (Participant, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 19 Years to 25 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
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%
Arms & Interventions
THC 0 + BAC .049
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.
Intervention: THC 10 (Drug)
THC 0 + BAC 0
Participants will receive 0mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: THC 0 (Drug)
THC 0 + BAC 0
Participants will receive 0mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: BAC 0 (Other)
THC 5 + BAC 0
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: THC 5 (Drug)
THC 5 + BAC 0
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: BAC 0 (Other)
THC 10 + BAC 0
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: THC 10 (Drug)
THC 10 + BAC 0
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .000%.
Intervention: BAC 0 (Other)
THC 5 + BAC .025
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .025%.
Intervention: THC 5 (Drug)
THC 5 + BAC .025
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .025%.
Intervention: BAC .025 (Other)
THC 10 + BAC .025
Participants will receive 125 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: THC 5 (Drug)
THC 10 + BAC .025
Participants will receive 125 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: BAC .025 (Other)
THC 0 + BAC .049
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.
Intervention: THC 0 (Drug)
THC 0 + BAC .049
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.
Intervention: BAC .025 (Other)
THC 0 + BAC .049
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .049%.
Intervention: BAC .049 (Other)
THC 5 + BAC .049
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .049%.
Intervention: THC 5 (Drug)
THC 5 + BAC .049
Participants will receive 5mg of THC in combination with blood alcohol concentrations of .049%.
Intervention: BAC .049 (Other)
THC 10 + BAC .049
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .049%.
Intervention: THC 5 (Drug)
THC 10 + BAC .049
Participants will receive 10mg of THC in combination with blood alcohol concentrations of .049%.
Intervention: BAC .049 (Other)
THC 0 + BAC .025
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: THC 0 (Drug)
THC 0 + BAC .025
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: THC 10 (Drug)
THC 0 + BAC .025
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: BAC .025 (Other)
THC 0 + BAC .025
Participants will receive 0 µg/kg of THC in combination with blood alcohol concentrations of .025%.
Intervention: BAC .049 (Other)
Outcomes
Primary Outcomes
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
Secondary Outcomes
- Visual Analogue Scale of Perceived Effects(@25 minutes and 2 hours)
- Perceptual Motor Speed & Efficiency as Measured by Time (in seconds) to Complete Trail Making Tests A&B(@25 minutes and 2 hours)
- Mean and Standard Deviation of Velocity in Meters/Second (STISIM Drive-Recorded Variable)(@2.5 hours)
- Standard Deviation of Lane Position in Meters (STISIM Drive-Recorded Variable)(@2.5 hours)
- Mean and Standard Deviation of Acceleration in Meters/Second (STISIM Drive-Recorded Variable)(@2.5 hours)
- Blood Pressure (Systolic/Diastolic mmHg)(@25 minutes and 2 hours)
- Electrical Brain Activity via EEG(Hour 0-3.5)
- Heart Rate (BPM) & Heart Rate Variability via ECG(Hour 0-3.5)
- Median Response Time and Efficiency in Alerting, Orienting & Executive Attention as Measured by the Attention Network Test (in milliseconds)(@25 minutes and 2 hours)