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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Demerit Points on Simulated Road Test
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
Time frame: @2.5 hours
Standard Deviation of Lane Position in Meters (STISIM Drive-Recorded Variable)
Recorded by the STISIM simulator during the simulation
Time frame: @2.5 hours
Mean and Standard Deviation of Velocity in Meters/Second (STISIM Drive-Recorded Variable)
Recorded by the STISIM simulator during the simulation
Time frame: @2.5 hours
Mean and Standard Deviation of Acceleration in Meters/Second (STISIM Drive-Recorded Variable)
Recorded by the STISIM simulator during the simulation
Time frame: @2.5 hours
Blood Pressure (Systolic/Diastolic mmHg)
Systolic \& diastolic blood pressure via automated blood pressure cuff
Time frame: @25 minutes and 2 hours
Heart Rate (BPM) & Heart Rate Variability via ECG
Continuous heart rate in beats per minute via 3-lead electrocardiography recording; will allow for calculation of heart rate variability)
Time frame: Hour 0-3.5
Electrical Brain Activity via EEG
Continuous brain activity via electroencephalography recording
Time frame: Hour 0-3.5
Median Response Time and Efficiency in Alerting, Orienting & Executive Attention as Measured by the Attention Network Test (in milliseconds)
A computerized test to measure participants' performance in three separate components of attention: alerting, orienting, and executive attention
Time frame: @25 minutes and 2 hours
Perceptual Motor Speed & Efficiency as Measured by Time (in seconds) to Complete Trail Making Tests A&B
A pen and paper test to measure perceptual motor speed and efficiency
Time frame: @25 minutes and 2 hours
Visual Analogue Scale of Perceived Effects
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
Time frame: @25 minutes and 2 hours
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.